Content uploaded by Nicola Di Stefano
Author content
All content in this area was uploaded by Nicola Di Stefano on May 20, 2024
Content may be subject to copyright.
Cognition 249 (2024) 105805
Available online 17 May 2024
0010-0277/© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-
nc-nd/4.0/).
Should absolute pitch be considered as a unique kind of absolute sensory
judgment in humans? A systematic and theoretical review of the literature
Nicola Di Stefano
a
,
*
, Charles Spence
b
a
Institute of Cognitive Sciences and Technologies, National Research Council of Italy (CNR), Via Gian Domenico Romagnosi, 18, 00196 Rome, Italy
b
Crossmodal Research Laboratory, Department of Experimental Psychology, University of Oxford, Oxford, UK
ARTICLE INFO
Keywords:
Auditory perception
Relative pitch
Eidetic memory
Savant syndrome
Sensory judgments
ABSTRACT
Absolute pitch is the name given to the rare ability to identify a musical note in an automatic and effortless
manner without the need for a reference tone. Those individuals with absolute pitch can, for example, name the
note they hear, identify all of the tones of a given chord, and/or name the pitches of everyday sounds, such as car
horns or sirens. Hence, absolute pitch can be seen as providing a rare example of absolute sensory judgment in
audition. Surprisingly, however, the intriguing question of whether such an ability presents unique features in
the domain of sensory perception, or whether instead similar perceptual skills also exist in other sensory do-
mains, has not been explicitly addressed previously. In this paper, this question is addressed by systematically
reviewing research on absolute pitch using the PRISMA (Preferred Reporting Items for Systematic Reviews and
Meta-Analyses) method. Thereafter, we compare absolute pitch with two rare types of sensory experience,
namely synaesthesia and eidetic memory, to understand if and how these phenomena exhibit similar features to
absolute pitch. Furthermore, a common absolute perceptual ability that has been often compared to absolute
pitch, namely colour perception, is also discussed. Arguments are provided supporting the notion that none of the
examined abilities can be considered like absolute pitch. Therefore, we conclude by suggesting that absolute
pitch does indeed appear to constitute a unique kind of absolute sensory judgment in humans, and we discuss
some open issues and novel directions for future research in absolute pitch.
1. Introduction
Absolute pitch (AP) has been dened as the ability to identify the
chroma (pitch class) of a tone presented in isolation or to produce a
specied pitch without external reference (e.g., Deutsch, 2013; Ward,
1999). It is often contrasted to relative pitch, the latter dened as the
ability to identify the name of a tone based on a reference tone and the
interval that the two tones form. Individuals with AP can, for example,
name the note they hear or play it directly without having to search for it
with a musical instrument, identify all of the tones of a given chord, or
sing a note once given the name. Individuals with AP might also be able
to identify and name the fundamental frequency of non-musical sounds,
such as car horns or sirens.
AP has long been a popular topic among those researchers working in
the eld of music perception.
1
In the late nineteenth century, Carl
Stumpf provided one of the rst scientic descriptions of the phenom-
enon Stumpf (1882, 1890), while empirical studies started to appear
around 1900 (e.g., Baird, 1917; Boggs, 1907; Gough, 1922; Kries, 1892;
Meyer, 1899; Weidensall, 1905; and Seashore, 1940; Neu, 1947, for
early reviews). Given the common psychological tenet that humans
perform poorly in tasks requiring absolute sensory judgments,
2
most of
these early researchers viewed AP as a rare ability and attempted to
* Corresponding author.
E-mail address: nicola.distefano@istc.cnr.it (N. Di Stefano).
1
The topic of AP is discussed extensively in Watt (1917) Psychology of Sound and there is a dedicated chapter in the key reference book for music psychologists
edited by Diana Deutsch as early as its rst edition in 1982. Interestingly, however, Moore devotes only one page to AP in his Psychology of Hearing across all six
editions from 1977 to 2012.
2
“An axiom of perceptual psychology has it that human beings are very poor absolute measuring instruments but are very good at comparing things” (Lawless &
Heymann, 1999, p. 301).
Contents lists available at ScienceDirect
Cognition
journal homepage: www.elsevier.com/locate/cognit
https://doi.org/10.1016/j.cognition.2024.105805
Received 3 November 2023; Received in revised form 12 April 2024; Accepted 23 April 2024
Cognition 249 (2024) 105805
2
describe its phenomenology and dening features.
3
Research on AP has increased a great deal over the recent decades,
with more papers published in the last twenty years (2003−2023) than
in the previous century (1899–2002) (190 vs. 87, see Table 1 Supple-
mentary material). Such an effort has generated robust insights con-
cerning several key psychophysiological mechanisms underlying the
perception of AP in humans (e.g., see Herceg & Szab´
o, 2023; Hou et al.,
2017; Kim & Kn¨
osche, 2017; Szyfter & Witt, 2020, for recent reviews).
Different related notions have also been introduced to account for the
complex phenomenology of AP (see Table 1).
In parallel, comparative research has investigated the perception of
AP in several mammals and avian species (see, e.g., Friedrich et al.,
2007; Hoeschele, 2017, for a review). However, an important caveat
should be made here regarding the meaning of AP in animal studies,
which is quite different from its occurrence in human studies. We refer
to the distinction between “general AP” and “musical AP” abilities, the
latter being related to naming and thus considered exclusively human,
while the former are related to discrimination (or production) of pitch
without external reference, an ability that can be present in animals,
such as songbirds (Weisman et al., 2006).
4
Consequently, the method-
ology adopted when testing non-human animals is different than that
adopted with humans, given the absence of linguistic counterparts of
pitch, and is mostly based on pitch discrimination tasks (see also Hulse
et al., 1984).
After more than a century of empirical research on the topic, the
accumulated evidence has converged on the suggestion that the ability
of those individuals with AP to name the pitch of (at least) one tone in an
automatic and effortless manner, and without the aid of any external
reference, clearly represents a case of reference-free sensory judgments
5
in humans. Surprisingly, however, the intriguing question of whether
such auditory ability presents unique features in the domain of sensory
perception would never appear to have been explicitly addressed pre-
viously. We thoroughly address this question in this paper. In Section 2,
we provide a systematic review of the multidisciplinary literature on AP
perception. We start by providing the details of the way the PRISMA
(Preferred Reporting Items for Systematic Reviews and Meta-Analyses)
guidelines have been implemented (Section 2.1). Then, we move on
to reviewing the studies investigating the genetic basis of AP (Section
2.2) and the neuroscientic (see Section 2.3), perceptual (see Section
2.4.1), and cognitive (see Section 2.4.2) mechanisms underlying AP.
Section 2.5 focuses on the perception of AP in clinical populations, such
as Autism Spectrum Disorder (ASD) and Williams syndrome. In Section
3, we move on to understanding if and how similar perceptual skills exist
in other sensory domains, by comparing AP with three phenomena that
share key phenomenological features with AP, namely synaesthesia (see
Section 3.1), eidetic memory (see Section 3.2), and colour perception
(see Section 3.4). Finally, in Section 4, we summarize the main ndings
of the review (see Section 4.1), answer the main question of this paper
(see Section 4.2), list some open issues (see Section 4.3), and suggest
some novel directions for future research in AP (see Section 4.4).
This systematic theoretical review contributes to the literature on
absolute pitch (AP) in several signicant ways. First, it provides a
comprehensive systematic review of the existing literature on AP. Sec-
ond, it offers a fresh perspective on AP, by reframing it within the
context of sensory skills rather than solely musical abilities and con-
ducting a thorough and illuminating comparison between AP and three
related absolute perceptual abilities. Third, it delves into the often-
overlooked question of the biological utility of AP, addressing open is-
sues in the eld. Finally, ve research directions for future studies to
further our understanding of AP perception are outlined.
2. Section 2
2.1. PRISMA review
Following the guidelines suggested in the PRISMA method (Moher
et al., 2009), we systematically review the research on AP from the rst
identied article published back in 1899 through to January 2024. The
document search was conducted through Scopus and Pubmed databases
using the following string: ‘absolute’ AND ‘pitch’ in the title or abstract
(and keywords, for Scopus database only). The inclusion criteria were:
full text available, written in English, and empirical articles. The
exclusion criteria were dened as well: books, commentaries, confer-
ence reports, editorials, articles in languages other than English, and
grey literature (non-academic reports or documents, or any other ma-
terial that did not pass the criteria for inclusion).
The initial search yielded a total of 705 records. Of these, 266 records
were immediately excluded as duplicates. We then screened the titles
and abstracts of the remaining 439 articles. 169 were manually excluded
for not being primarily related to AP in humans (e.g., comparative
studies), conceiving the terms in a different way (e.g., related to the
processing of AP compared to relative pitch instead of individuals with
AP), being review or preprint articles, or not being related to the
research question. The remaining 270 records were considered fully
eligible as meriting further analysis (see Fig. 1). Articles were catego-
rized according to the following categories: studies investigating the
genetic dimension of AP (n =14); neuroscientic/psychophysiological
studies (n =95); behavioural studies (n =131); studies on clinical
population (e.g., ASD, Williams syndrome, blind) (n =30) (see Fig. 2
Table 1
List of the relevant notions that have been evoked in the psycho-musicological
literature on AP.
Terms Description Sources
Absolute pitch The ability to identify the chroma
of a tone presented in isolation
using pitch labels or to produce a
specied pitch without external
reference
Deutsch, 2013;
Miyazaki, 2004a;
Ward, 1999
Relative pitch The ability to identify the name of a
pitch given an external reference
Deutsch, 2013; Ward,
1999
Pitch memory The stable and long-term memory
for pitch (without the ability to
name it)
Schellenberg &
Trehub, 2003
Perfect pitch Extraordinary acuity in the
discrimination of the frequency of
tones
Parncutt & Levitin,
2001
Quasi-absolute
pitch
The ability to identify one pitch and
use it as a reference for measuring
the intervals
Bachem, 1937, 1955
Tone pitch Equivalent to absolute pitch Parncutt & Levitin,
2001
Piece pitch The ability to recognize whether a
familiar piece is played in the
correct key (passive), or singing a
familiar song in the correct key
(active)
Parncutt & Levitin,
2001
(Relatively)
absolute tonality
Ability to recognize whether a
known melody/piece is played in
the original key
Ward, 1999
Instrumental pitch
(or piano pitch)
The ability to recognize tones only
when produced by a specic
instrument, which often turns out
to be the piano
Levitin & Rogers,
2005
3
Interestingly, an often conceptually associated similar phenomenon, namely
synaesthesia, has a quite similar historical evolution (e.g., Cytowic, 1997). We
will focus on the relationship between AP and synaesthesia in Section 3.1.
4
In this paper, we primarily refer to musical AP, given that the ability to
identify pitches verbally or in any other direct way is crucial for AP.
5
We use the term “sensory judgment” to indicate one of the most prototyp-
ical ways AP skills are tested in the empirical literature, that is, by asking
participants to verbally identify a musical note (“this sound is a C").
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
3
below and Table 1 in Supplementary material). The main ndings for
each category are reviewed in the following Sections 2.2–2.5.
2.2. Genetic and ethnicity studies
While the prevalence of AP in the general population has been
estimated at about 0.01–1% (Bachem, 1955; Levitin & Rogers, 2005;
Ward, 1999),
6
these numbers increase signicantly in specic cultures
and populations, thus suggesting that there might be genetic pre-
dispositions toward certain of the underlying traits necessary for the
development of AP. Several studies have been conducted to investigate
Fig. 1. PRISMA ow diagram.
Fig. 2. Academic papers published on the topic of AP per decade and category.
6
The reliability of these values has been questioned by Carden and Cline
(2019) given that the data on which the estimate is based is not available in the
original source of Bachem (1955).
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
4
the familial or ethnic predispositions or advantages in AP perception.
One of the earliest was a segregation study conducted by Prota et al.
(1988), who reported signicant familial incidence in 35 AP probands
from 19 families. A subsequent familial aggregation study yielded a
sibling recurrence risk-ratio estimate of 20, meaning that siblings of AP
possessors are approximately 20 times more likely to possess AP relative
to the general population (Gregersen & Kumar, 1996). Further studies
by Gregersen et al. (1999, 2001) obtained lower, though still signi-
cantly higher than normal, values (i.e., of 8.3 and 12.2, respectively, see
also Baharloo et al., 1998; Baharloo et al., 2000). A recent study by
Bairnsfather, Ull´
en, Osborne, Wilson, & Mosing (2022) documented a
signicant correlation between pitch-naming scores for monozygotic (r
=0.27, p <.001) but not dizygotic twin pairs (r = − 0.04, p =.63), with
the age of onset no longer being a signicant predictor once practice was
considered in twins. These ndings are in line with the notion that the
pitch-naming ability is associated with both genetic factors and the
amount of early practice, rather than just age of onset per se.
Inconsistencies among familial studies might be explained, as
observed by Tan et al. (2014), by noting that familial aggregation does
not distinguish between genetic and environmental contributions to a
trait, making it possible that the high familial aggregation estimates
stem from environmental inuences such as early music training, which
has been identied as a key environmental determinant of AP (Miyazaki,
1988; Prota & Bidder, 1998; Sergeant, 1969; Wilson et al., 2009). At
the same time, those children who excel at pitch-naming may have an
increased tendency to practice, thus partially explaining the higher
percentage of AP possessors in this samples.
Other evidence relates to an ethnicity cluster for AP; namely that a
higher rate of AP has been documented among Asian students as
compared to Caucasian students (47.5% vs 9%, respectively, see Gre-
gersen et al., 2000; though see Schellenberg & Trehub, 2008). Note that
this is not attributable to sociocultural variables, because the elevated
rate has also been documented in North Americans of Asian descent (cf.
Levitin & Rogers, 2005) or to early exposure to tonal languages, given
that the sample included people from Korea and Japan. Miyazaki
(2004a, 2004b) estimated that in Japan the proportion of individuals
with AP is approximately 30% for university students of music education
and 50% or more for music students (see also Gregersen et al., 1999,
2000). More recently, Miyazaki et al. (2018) investigated AP abilities in
a sample of music students from East Asian and Western countries
(Japan, China, Poland, Germany, and the USA). The conservatory-level
Japanese students showed the highest AP performance and more than
half of them were classied as accurate AP possessors. In contrast, only a
small percentage of the participants from Poland, Germany, and the USA
were identied as accurate AP possessors, with participants from China
intermediate on AP measures (see Chavarria-Soley, 2016, on listeners
from Costa Rica).
However, as observed earlier, ethnic differences might be explained
by observing that people with AP tend to take music education or
training courses more likely than normal perceivers. Different peda-
gogical traditions might partially account for these differences, given
that Asians are signicantly more likely to receive ‘xed pitch training’
(i.e., reinforcing tone/name associations), such as embodied by the
Suzuki method, as compared with Caucasians (29% of Asians vs. 6% of
Caucasians, p =.001, in the sample examined by Gregersen et al., 2000;
see also Gregersen et al., 1999).
Possible ethnicity effects for AP can also be observed from a genome-
wide linkage study of 73 families of European, East Asian, Jewish, and
Indian descent in the United States and Canada (Theusch, Basu, &
Gitschier, 2009) and a similar study of AP families (in which multiple
family members have AP) and with synaesthetic families (in which
multiple family members have synaesthesia; Gregersen et al., 2013).
2.3. The neuroscience of AP
Several studies have investigated the neuroscience of AP perception,
leading to the identication of the neurological, structural, and
functional correlates of AP (e.g., Dohn et al., 2015; Elmer et al., 2015;
Itoh et al., 2005; Oechslin, Meyer and J¨
ancke, 2010; Ohnishi et al., 2001;
Loui et al., 2011; Keenan et al., 2001; J¨
ancke et al., 2012; Schlaug et al.,
1995; Wilson et al., 2009; Zatorre, 2003) see also Hou et al., 2017; Kim
& Kn¨
osche, 2017; Loui, 2017, for reviews). The accumulated evidence
has led to the identication of two brain regions that are prominently
involved in the processing of pitch by individuals with AP, namely the
left posterior dorsolateral frontal cortex (DLFC) and the planum tem-
porale (PT).
The role of the DLFC during pitch naming was suggested by an early
study by Zatorre et al. (1998) and later conrmed by a number of other
studies (Bermudez & Zatorre, 2005; Ohnishi et al., 2001; Schulze et al.,
2009; Wengenroth et al., 2014). Known to be involved in tasks that
require working memory (e.g., Blumenfeld & Ranganath, 2006; Pet-
rides, 2000), the DLFC should facilitate AP musicians’ ability to retrieve
the learned associations between pitch and verbal labels. The results
from a recent Stroop-like task with AP musicians conrmed the causal
relationship between the left DLFC and pitch labelling, the latter
emerging as an automatic and largely irrepressible process triggered by
the exposure to musical tones (Rogenmoser et al., 2021).
7
Another important region for AP ability is the PT, located in the
posterior portion of the superior temporal gyrus (STG) (Clark et al.,
2010). The involvement of the PT in pitch processing has been consis-
tently implicated in a large number of studies (see Grifths & Warren,
2002, for a review). Functional neuroimaging studies yielded positive
correlations between the left PT activation and AP prociency among AP
musicians during pitch naming (Wilson et al., 2009; Zatorre et al.,
1998), with some evidence suggesting that pitch chroma and pitch
height are processed separately in the anterior and posterior parts of the
superior temporal planes, respectively (Warren et al., 2003).
8
A recent MEG study by Benner et al. (2023) conrmed the activation
of PT induced by complex harmonic tones and provided original insights
into the temporal dynamics of brain responses at the location of corre-
sponding fMRI activations. In the AP group, the auditory evoked P2
onset occurred ~25 ms earlier in the right as compared to the left PT and
~ 15 ms earlier in the right as compared with the left anterior STG. This
effect was consistent at the individual level and correlated with AP
prociency. Based on the combined application of MEG and fMRI
measurements, the authors were for the rst time able to demonstrate a
characteristic temporal hierarchy – they called it “chronotopy” – of
human auditory regions in relation to specic auditory abilities,
reecting the prediction for serial processing from nonhuman studies.
Shorter latencies of N100 responses in AP musicians compared to non-
AP musicians and non-musicians have been also recently conrmed by
Sharma et al. (2023) using high-density electroencephalographic
recording.
Neuroanatomical studies demonstrated stronger left surface/volume
asymmetry in PT among AP musicians associated with increased AP
accuracy (Grifths & Warren, 2002; Schlaug et al., 1995). It has been
observed that this asymmetry may be driven by a smaller right PT sur-
face rather than a larger left surface (Keenan et al., 2001; Loui et al.,
2011; Schlaug et al., 1995; Wilson et al., 2009). However, the role of PT
asymmetry in AP remains somewhat controversial, given Zatorre’s
(1989) ndings that AP ability was unchanged after surgical excision of
the left PT (which implies that the right PT may play a role in AP ability).
Putting together evidence on DLFC and PT, Hou et al. (2017) sug-
gested that the bilateral PT and the left posterior DLFC may form a
7
The role of the left posterior DLFC in associative learning and memory has
also been veried in nonhuman primate studies (Bermudez & Zatorre, 2005;
Katsuki et al., 2022; Qi et al., 2010).
8
More generally, the PT is implicated in auditory language processing,
including perception of phonemes (units of speech; Grifths & Warren, 2002).
Phonemic categories of speech might be held similar to musical pitch cate-
gories, which are, of course, crucial for AP ability.
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
5
functional pathway that is implicated in AP ability, which might result
in part from the interactions between the PT/posterior DLFC and a
network of other brain regions that are implicated in the retrieval and
manipulation of various types of associations with pitch (Zatorre et al.,
1998), including verbal-tonal associations (Ohnishi et al., 2001; Petrides
& Pandya, 1988, for relevant ndings in primates).
The early case report of epileptic patients with AP by Zatorre (1989)
poses interesting questions about the hemispheric specialization in AP.
In that study, AP recognition in the patient was intact after anterior
temporal lobectomy of the left hemisphere, a result which led the author
to suggest the right-hemispheric domination in AP (Zatorre, 1989).
More recently, Wengenroth et al. (2014) identied a right hemisphere
network for AP perception, including the right premotor and secondary
somatosensory cortices, the right inferior frontal gyrus, and the right
middle temporal gyrus. These function together with the right PT, the
left posterior DLFC, and the left Broca’s area – regions that are involved
in conditional association pitch memory and motor aspects of speech
performance, respectively (Bermudez & Zatorre, 2005; Zatorre et al.,
1998) – instrumental for pitch labelling.
However, studies also indicate that hemispheric dominance might be
inuenced by the different AP skills of individuals. For example, while
reporting the engagement of the right hemisphere in individuals with
lower AP skill, the study by Wilson et al. (2009) showed a left hemi-
sphere advantage among AP musicians, thus indicating that AP and
quasi-AP or lower AP possessors might use different strategies (i.e.,
working memory) and thus recruit different neural circuitries.
9
Indeed,
several ERP studies showing decreased P300 amplitudes and latencies
among AP musicians (Crummer, Walton, Wayman, Hantz, & Frisina,
1994; Klein, Coles, & Donchin, 1984; Wayman et al., 1992; see also Itoh
et al., 2005) have been interpreted as indicating less working memory
involvement during pitch naming by AP due to their reliance on tonal
templates (Berti & Roeber, 2013; Ruhnau et al., 2010; Schomaker &
Meeter, 2014; though see Hirose et al., 2002 for null ndings on P300).
Overall, the literature reviewed here suggests that AP is associated with
integration across multiple brain regions that together form a complex,
functionally interconnected network. Other neuroimaging studies have
demonstrated the involvement of a number of brain areas in AP musicians
during naming, including the superior temporal gyrus (Zarate & Zatorre,
2008) and the middle frontal gyrus (Wilson et al., 2009). Both the right
inferior frontal and right occipital gyri are also activated (Zatorre et al.,
1998). The superior temporal gyrus is implicated in auditory processing,
including in the perception of phonemes (units of speech; Grifths &
Warren, 2002; Oechslin, Imfeld, et al., 2010). Superior temporal gyrus
activation during pitch naming has been shown to be positively correlated
with AP prociency (Ohnishi et al., 2001; Wilson et al., 2009; Zatorre
et al., 1998). The inferior frontal gyrus subserves semantic functions
(Platel et al., 2003), the middle frontal gyrus is implicated in sensorimotor
functions with auditory signals (Wan & Schlaug, 2010), and the occipital
gyrus subserves vision and visual imagery functions (Schmithorst, 2005).
This suggests a potential functional network including the left posterior
DLFC and additional regions, since the DLFC is linked to other implicated
brain regions, and lesions to it impair acquisition of arbitrary associations
between stimuli and responses (Petrides, 2000).
The literature that has been reviewed here also highlighted some
inconsistent results. For instance, regarding P300 brain responses (Klein,
Coles, & Donchin, 1984; Hirose et al., 2002), and the involvement of
working memory in AP labelling. Assuming that AP ability emerges from
two separate processing stages – the rst being an early phase of pitch
encoding, the second being the associative mechanism that categorizes
pitches with verbal labels (or any other abstract coding) – the
inconsistencies might depend on the fact that AP possessors use different
strategies to associate pitch with labels and each strategy might, in turn,
recruit different neural circuitries (e.g., verbal coding, semantic memory,
auditory, kinesthetic, visual, and spatial imagery). For instance, Siegel
(1974) found that AP musicians retained pitch information by using verbal
labels to remember tone information, while Zatorre and Beckett (1989)
found that AP musicians can encode music pitches verbally. This expla-
nation would receive support by results showing no group difference be-
tween AP and non-AP musicians in neurophysiological indicators of early
sensory processing while passively listening of tones (Elmer et al., 2013).
2.4. The behavioural evidence
2.4.1. AP perception. AP is often reported to be an automatic ‘perceptual
expertise’ among those who possess it (e.g., Bachem, 1937; Ward, 1999),
and one that those who have it are unaware of the way in which it func-
tions exactly. The former claim is supported by the wide body of evidence
showing that individuals with AP identify pitches effortlessly and
immediately (e.g., Bachem, 1940; Prota et al., 1988; Revesz, 1953;
Rogenmoser et al., 2021) and report having made no special effort to
develop AP (Baird, 1917; Boggs, 1907; Levitin & Rogers, 2005, for a
review).
Research in humans suggests that AP turns out to be the result of an
allegedly innate individual predisposition, although a few cases have
been demonstrated of the acquisition of AP by adults (e.g., see Van
Hedger et al., 2019; Wong et al., 2020). The literature suggests that AP
emerges early in human development, typically between 3 and 6 years of
age, and is strongly correlated with musical education (Miyazaki, 2004a;
Takeuchi & Hulse, 1993). Such an ability tends to remain throughout
life, although it might shift a little in tuning (e.g., see, Vernon, 1977).
10
However, it might also be lost due to traumatic neurological events. The
study by Katsuki et al. (2022) reported the case of a 68-year-old musi-
cian who lost AP due to a hemorrhage edematous lesion under the pos-
terior insular cortex. Remarkably, as the hematoma was absorbed, her
AP ability recovered. Moreover, studies have shown that AP can be
temporarily affected by certain drugs, such as carbamazepine (Braun &
Chaloupka, 2005; Fujimoto, Enomoto, Takano, & Nose, 2004; Konno,
Yamazaki, Kudoh, Abe, & Tohgi, 2003).
Often presented as an ability individuals either are or are not endowed
with, AP is thus likely best seen as a spectrum of skills, a distributed and
multifaceted ability rather than a static and dichotomous one. The mani-
festations of AP signicantly vary across those individuals who possess it
in terms of accuracy, response time, preferred timbre, and means of
identication of the pitch (e.g., verbal or playing). The perception of AP is
often considered as categorical, with different responses to differences
within a category (of, say, C) and to transition into a new one (C#).
The most prominent manifestation of AP is the ability to name the pitch
immediately after hearing it. The literature shows that the percentage of
correct identications varies widely in the literature, between 70% and
99% (Takeuchi & Hulse, 1993).
11
This variability might be attributable to
individual factors, the nature of the stimuli, and the experimental
9
However, Suriadi et al. (2015) showed intact AP abilities after selective
amygdalohippocampectomy of the right hemisphere, thus suggesting that AP
might be relatively independent of medio-temporal structures, particularly the
hippocampus.
10
Explanations for this effect have been formulated, highlighting the impact
of age on the mechanical properties of the basilar membrane (e.g., elasticity),
with cascading effects on pitch processing (Ward & Burns, 1982).
11
Baharloo et al., 1998 distinguished between four groups of AP possessors.
The rst group includes those individuals who were able to label any pitch
regardless of its timbre and spectral region. Individuals who performed at a
level that was signicantly above-chance, but who performed at progressively
lower levels for pure tone labelling than the rst group, formed the remaining
three groups, depending on their scores. Similarly, Miyazaki (1990) arbitrarily
classied those individuals with AP into three subgroups according to the
following values of accuracy in AP tests: >90%, 70–90%, <70% (and
apparently with a minimum threshold of 30%, see Miyazaki, 1990, Fig. 1, p.
179). Importantly, all individuals were considered AP possessors.
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
6
protocols used. For example, individuals with AP are typically more ac-
curate in identifying the names of pitches (pitch classes) rather than the
exact octave, thus suggesting that they adopt a two-stage process in which
they identify the pitch class of the presented tone and then locate its octave
position (Miyazaki, 2004a). However, the percentage of correct identi-
cations is far higher than chance in all of the experiments that have been
reported to date, with the most accurate identications being the fastest,
both within and across participants (Baird, 1917; Carroll, 1975; Miyazaki,
1988, 1989; Whipple, 1903). Individuals with AP might also be able to
sing or reproduce the tone they have heard on an instrument, or identify
the key of a piece (Deutsch, 2013; Ward, 1999).
AP can be enhanced by association or integration with other perceptual
or cognitive parameters (Siegel, 1974; Zatorre & Beckett, 1989). For
example, AP is enhanced as a result of linking pitches to colours, a phe-
nomenon that might be related to chromaesthesia or coloured hearing,
although the latter are associations that occur involuntarily and auto-
matically (Peacock, 1985; Rogers, 1987; Spence & Di Stefano, 2022, for a
review). Timbre might also facilitate, or at least affect, AP perception, with
musicians tending to identify the tones of their main instrument more
reliably and more rapidly than other timbres (Lockhead & Byrd, 1981;
Marvin & Brinkman, 2000). When the preferred timbre is that of the piano,
the AP has been labelled as piano-pitch (Levitin & Rogers, 2005).
Intriguingly, among pianists, the identication of tones corresponding to
the black keys on the keyboard is typically less accurate than white-key
notes (Miyazaki, 2004a, 2004b see also, Dohn et al., 2012).
12
Surprising as it may sound, AP possessors and non-possessors have
equivalent acuity and perceptual thresholds for pitch differences (see
Levitin, 2004). However, AP has often been considered a clear sign of
musical talent, and many musical geniuses were endowed with this
particular ability. Mozart was one such gifted composer. He displayed this
ability when he was 7 years old, as reported in the following passage from
an anonymous letter: “I saw and heard how, when he was made to listen in
another room, they would give him notes, now high, now low, not only on
the pianoforte but on every other imaginable instrument as well, and he
came out with the letter of the name of the note in an instant. Indeed, on
hearing a bell toll or a clock, even a pocket-watch, strike, he was able at the
same moment to name the note of the bell or timepiece.” (Augsburgischer
Intelligenz-Zettel, 1763, cited in Deutsch, 1990, p. 21). Other great com-
posers, such as Beethoven, Bach, and Handel also possessed AP (Deutsch,
2002), thus contributing to the notion that such an ability is often a
hallmark of extraordinary musical ability.
The ability to perceive pitch absolutely, though, negatively impacts
some musical tasks, such as producing transpositions in pitch (Miyazaki,
2004b; Revesz, 1953; Ward, 1999; Wilson, 1911). An individual with AP
who reads G4 in a musical score but is asked to transpose (i.e., sing or
play) it one tone higher will have to produce A4, with conicting in-
formation between the written and sounded pitches. There is evidence of
a Stroop-like interference effect in those individuals with AP when asked
to identify pitches. For instance, Zakay et al. (1984) demonstrated that
participants were slower and more prone to error when identifying tones
sung with an incongruent pitch name (e.g., the pitch D4 sung on the
syllable “do”) than when identifying pitches sung on a neutral syllable.
This strengthens the notion that absolute perception occurs immediately
and involuntarily and, in certain situations, can interfere with the
perception of pitch relations.
13
Although AP has a clear perceptual basis, there are reasons to doubt
that the perceptual system directly and simply maps physical fre-
quencies onto pitch categories. If there were such a system of direct
mapping, the only variability in note identication performance would
arise from differences in the perception of frequency, but this is not the
case. For example, although two people might both perform well enough
on a musical note identication task to be considered to have AP, they
can show signicant differences in performance with specic timbres,
notes, or frequency ranges (e.g., see Bahr et al., 2005).
Moreover, cases of individuals who can identify the frequency of a
tone but cannot name it suggest that having perceptual and discrimi-
nation skills as rened as those of AP possessors is not sufcient to give
rise to AP. For instance, Halpern (1989) found that those adults without
AP consistently sang familiar melodies starting on the same pitch. The
starting pitch varied from song to song and varied across participants
but was consistent within individuals over several repetitions of the
same song, even when the repetitions were separated by a couple of
days. In a similar way, Schellenberg and Trehub (2003) demonstrated
that adults with little musical training can remember the pitch level of
familiar instrumental recordings, as reected in their ability to distin-
guish the correct version from versions that have been shifted upward or
downward by 1 (58% correct answers, p <.001) or 2 semitones (70%
correct answers, p <.001). Together with other ndings (Levitin, 1994;
Terhardt & Seewann, 1983; Terhardt & Ward, 1982), these results
suggest that normal perceivers can accurately encode a specic starting
pitch for melodies and can retrieve this starting pitch reliably. Should
those individuals be able to name the starting pitch, they would satisfy
one of the requisites of quasi-AP, i.e., the ability to identify a pitch
(Bachem, 1937, 1955).
Finally, if the ability to directly identify the pitch of a tone relies on
an extraordinary perceptual skill that allows individuals to exactly
match frequency with pitch, why is this ability restricted to the tuning of
the scale system to which the particular listener is accustomed? In other
words, why does an extraordinary perceiver with AP recognize only
those qualities represented by the twelve pitches of our tempered tuning
system, given that normal perceivers can discriminate very small
changes in frequency along the audible range (i.e., few Hz in the range
1000–4000 Hz, see Fastl & Hesse, 1984)? These questions lead us to
assume that the mapping between frequency and pitch class cannot be
fully explained in perceptual terms, given that pitch naming does not
merely translate the ne-grained discreteness of frequency discrimina-
tion. In what follows, we consider the cognitive dimensions that alleg-
edly play a role in prompting the mapping, focusing especially on the
role of memory.
2.4.2. The cognitive mechanisms underlying AP: learning and memory.
Levitin (1994) suggested that AP consists of two distinct component
abilities: (1) the ability to maintain stable, long-term representations of
specic pitches in memory, and to access them when required, namely
pitch memory; and (2) the ability to attach meaningful labels to these
pitches, such as A to 440 Hz, namely pitch labelling. Levitin and Rogers
(2005) subsequently observed that AP, conceived of as the ability to
name pitches, is probably acquired just like other perceptual labels in
the developing child’s vocabulary. The acquisition of pitch categories
might parallel that of colour categories, for both of which the child must
learn to distinguish one perceptual quality (pitch chroma, or hue) from
several other perceptual attributes as a prerequisite to creating the
correct mappings between tone (or colour) and its linguistic label.
Although it is unclear how and why the pitch-name associations are
formed in a relatively automatic manner in certain individuals, it should
be noted that most children are not taught pitch labels. Given that in-
dividuals with AP report having had musical training, one of the most
parsimonious ways in which to explain the perception of AP would
therefore seem to assume that individuals have learned the association
during development through musical training. Such an explanation is
12
This might depend on the fact that tones corresponding to black keys are
relatively less frequent in the exercises or excerpts individuals practice when
they start learning how to play the piano.
13
Regarding the importance of relative versus absolute processing of pitch in
music, it might be worth going back to an observation made more than a
century ago by Henry Watt, a Scottish experimental psychologist: “Absolute
ears emerges when the natural absoluteness of tonal orders maintains its ef-
ciency is spite of the tremendous emphasis laid on relativity or proportion in
music" (Watt, 1917, p. 200).
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
7
consistent with evidence showing that AP possessors and normal per-
ceivers have equivalent acuity and perceptual thresholds for pitch dif-
ferences and that timbre-dependent AP is often piano-dependent, given
that the piano is one of the most frequent timbres that listeners are
exposed to during the development and one of the most popular in-
struments present at home (see Levitin, 2004; Levitin & Rogers, 2005).
Hence, AP would be essentially mediated by two key interrelated fac-
tors, namely perceptual learning and memory.
Interesting evidence comes from those studies, though relatively
scarce, proving that some adults with no AP have been trained and
eventually learned AP. For instance, Wong et al. (2020) trained adult
participants, mostly Cantonese speakers, to learn the names of pitches
through a series of experiments that included a computerized, gamied,
and personalized training protocol for 12 to 40 h. The results demon-
strated that AP learning showed classic characteristics of perceptual
learning, with 14% of the participants (6 out of 43) being able to name
twelve pitches with an accuracy of 90% or above, comparable to that
dened in the literature for individuals with AP (see also Van Hedger
et al., 2019, for similar results obtained on a smaller number of partic-
ipants). Such a high level of accuracy is even more surprising, consid-
ering that the participants’ training lasted between 12 and 40 h in total,
which is signicantly shorter time of exposure and training compared to
the time a child devotes to musical training in the rst years. Addi-
tionally, Van Hedger et al. (2015) have demonstrated that auditory
working memory capacity predicts the efcacy of learning AP note
categories, thus supporting the idea that a larger auditory short-term
memory might underlie the formation of AP categories.
The role of learning is also suggested by the fact that AP is a
language-mediated ability, and that the critical period for the acquisi-
tion of AP is thought to be similar to that of language development
(Chin, 2003; Deutsch et al., 2009). This would thus imply that the ge-
netic predisposition might be necessary but is clearly not sufcient: tone
labels must still somehow be learned.
14
Further support for the medi-
ating role of memory might be undirectedly provided by ndings
showing that individuals with AP perform better on certain pitch
memory tasks (Bachem, 1954; Rakowski & Rogowski, 2007; Siegel,
1974), such as being able to indicate, after a 1-week interval, whether a
standard tone and a comparison tone are the same or different (Bachem,
1954). This likely demonstrates that they can assign verbal labels to
pitch classes, due to their rened abilities to apply a verbal encoding
strategy, and easily recall them after a relatively long time.
15
Given the prominent role of memory and perceptual learning,
however, it might be surprising that only a small fraction of musicians
possesses AP (ranging between 4 and 18% in Westerners, see Carden &
Cline, 2019), given that for many years these individuals are exposed to
the association between pitches and pitch labels. It would be similarly
difcult to explain why the incidence increases to 50–60% among Asian
musicians (e.g., Chinese or Japanese) (Deutsch, 2006; Miyazaki,
Makomaska, & Rakowski, 2012). Moreover, after years of practicing,
most musicians naturally learn by heart a number of musical composi-
tions, to the point that they can write the exact score from memory;
however, this ability does not lead to AP, not even limited to the notes of
the learned score. In contrast, most musicians develop a rened ability
to recognize other important auditory properties, such as timbre. Timbre
identication is such a sophisticated ability that musicians (but occa-
sionally also non-musicians) might be able to identify not only the in-
strument or the voice they hear, but also the instrumentalist or the
singer. For instance, when hearing Bach’s Chaconne for violin, they can
recognize whether Heifetz or Vengerov is playing, or when hearing
Verdi’s aria Questa o quella, they can recognize the voice of Domingo or
Pavarotti. These considerations strengthen the idea that exposure and
learning are critical in the acquisition of AP but cannot in themselves
account for this ability.
To summarize, the ability of those individuals who possess AP
seemingly rests on an auditory-semantic correlation, namely between
tone names (i.e., scale steps) and their usual approximate pitches. This
rare ability may thus be seen as resulting from the combination of
various components, namely memory, a particular (genetic) predispo-
sition, and formal and explicit musical training. To delve deeper into the
biological and acquired factors of AP, in the next section, the evidence
indicating a purportedly higher prevalence of AP skills among in-
dividuals with neurodevelopmental disorders and visual impairment is
reviewed.
2.5. AP in clinical populations
Several studies have investigated the relationship between extraor-
dinary perceptual skills, including AP, and neurodevelopmental disor-
ders such as ASD and Williams syndrome (e.g., Bonnel et al., 2003;
Heaton, 2003; Heaton et al., 1998; Lenhoff et al., 2001; Masataka, 2017;
Meilleur et al., 2015). These studies are motivated by the observation
that these perceptual skills are more often prevalent among individuals
with those disorders than among control participants. For instance, the
prevalence of AP has been estimated as about 0.01–1% in typical pop-
ulations (see §2.2) but has been reported to vary between 5% and 11%
in individuals with ASD (Bonnel et al., 2010; Romani et al., 2021;
Kupferstein & Walsh, 2016, reports much higher values, i.e., 97% in
people with autism, though the same study reports about 50% of neu-
rotypicals to manifest AP-like abilities).
The participants tested in a study of ASD and typically-developing
children reported by Masataka (2017) heard 36 pure sine wave tones,
presented in pseudo-randomized order, which ranged from A3 to A5,
with each tone being presented once. The participants had to answer the
tonal label after hearing the accordant tone. In a sample of 19 ASD
children, 15 exceeded the chance level in a test of AP ability, while the
accuracy of all of the typically-developing children remained indistin-
guishable from chance.
A number of studies have revealed a heightened pitch discrimination
and identication ability in those with ASD as compared to controls
(Bonnel et al., 2003; DePape, Hall, Tillmann, & Trainor, 2012; Heaton,
2003; Heaton et al., 1998; Meilleur et al., 2015).
16
Additionally, chil-
dren with ASD demonstrated a superior pitch discrimination ability in
the melodic context and stronger long-term memory for melody (Stanutz
et al., 2014). However, when it comes to vocal imitation, individuals
with ASD have shown inferior performance to controls on AP and
duration matching for speech and song imitation, while performing as
well as controls on relative pitch and duration matching (Wang, Pfor-
dresher, Jiang, & Liu, 2021).
To date, fewer studies have explored the correlation between AP
skills and Williams syndrome. Lenhoff et al. (2001) demonstrated that
14
This might suggest a further parallel with language acquisition, given that
human infants are equipped at birth to learn any language and can perceive and
discriminate between differences in all human speech sounds. For example, 4-
month-old Japanese infants can distinguish the /r/ and /l/ sounds in English as
reliably as 4-month-olds raised in English-speaking households. Later on,
however, infants tend to exhibit a preference for phonemes in their native
language over those in foreign languages and by the end of their rst year no
longer respond to phonetic elements peculiar to non-native languages. In
accordance with the idea of a critical period for AP acquisition, the ability to
perceive these phonemic contrasts evidently persists for several more years,
until about the age of 7 or 8 years. After this point, similar to AP ability, per-
formance gradually declines no matter what the extent of practice or exposure
(Purves et al., 2001).
15
Here it might be worth mentioning that motor memory could have a role in
certain occurrences of AP, such as quasi-AP or pseudo-AP. For instance, a singer
might have motor memory about the way they produce a specic pitch, and use
it as reference tone (e.g., Levitin, 1994).
16
Furthermore, several single case reports have been published on this, such
as Brenton et al. (2008), Heaton et al. (2008), Mottron et al. (1999), and
O’Connell (1974).
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
8
the ve individuals they tested, who have Williams syndrome, exhibited
near-ceiling levels of AP. However, these ndings contrast with those of
Martínez-Castilla, Sotillo, & Campos (2013), who conducted two ex-
periments involving a total of 34 individuals with Williams syndrome
and compared them to 58 typically-developing participants. Using a
traditional assessment of AP, they observed that individuals with Wil-
liams syndrome and their controls achieved low results in the AP task.
Their responses showed an arbitrary pattern, and their performance fell
signicantly below that of musicians with AP, suggesting that AP is also
rare in individuals with Williams syndrome.
The prevalence of AP skills has also been investigated in blind people
(Gaab, Schulze, Ozdemir, & Schlaug, 2006; Hamilton et al., 2004;
Welch, 1988; see also Pring et al., 2008). In an early observation by
Welch (1988), the incidence of AP in early blind individuals (i.e., either
congenitally blind or due to an accident occurring in the rst days
following birth) was much higher than in sighted individuals, with
64.7% of blind participants (22 out of 34) showing AP skills. Similar
values were later obtained by Hamilton et al. (2004) on a sample of 21
early blind participants who received musical training, 12 of whom
(57.1%) reported having AP, reecting markedly increased prevalence
compared to sighted musicians. Additionally, magnetic resonance im-
ages acquired in a subset of blind AP musicians revealed greater vari-
ability in PT asymmetry compared with the increased left-sided
asymmetry previously described in sighted individuals with AP (see
Section 2.3), suggesting that the neural mechanisms underlying AP in
blind individuals could differ from those in the sighted. The difference in
neural correlates of AP has been conrmed by Gaab and colleagues
(2006), who demonstrated that the brains of blind musicians exhibited
signicantly more activation in bihemispheric visual association areas,
the lingual gyrus, and parietal and frontal areas compared to sighted
musicians. Conversely, sighted musicians displayed more activation in
the right primary auditory cortex and the cerebellum when compared
with blind musicians (Gaab et al., 2006).
3. AP and synaesthesia, extraordinary memory, and colour
perception
In the previous sections, the various elements that contribute to
making AP, at least in its prototypical manifestation, a rare example of
reference-free sensory judgment in audition have been thoroughly
reviewed. However, it remains unclear whether this auditory ability is
not only statistically rare among individuals, but also rare or unique in
the spectrum of sensory/perceptual abilities. In the following sections,
we will take a closer look at three occurrences of sensory judgments that
have been occasionally, and often anecdotally, related to AP, namely
synaesthesia (see Section 3.1), eidetic memory (see Section 3.2), and
colour perception (see Section 3.4), in the attempt to understand if and
how these phenomena exhibit similar features to the phenomenon of
absolute pitch.
3.1. Synaesthesia and AP
Synaesthesia is the rare neurological condition in which specic
inducing stimuli give rise to an additional idiosyncratic concurrent
experience in either the same or different sensory modality; these syn-
aesthetic experiences are involuntarily and automatically triggered,
highly-specic, and consistent over time (Cytowic, 1997; Grossenbacher
& Lovelace, 2001). Over the years, several different theories have been
put forward to explain the existence of synaesthesia (see Simner &
Hubbard, 2013, for a review). Here, we will mainly consider those cases
of synaesthesia in which an inducer in one sensory modality gives rise to
a concurrent in a different sense. For our purposes, we will focus on
music-colour synaesthesia, in which a musical stimulus (the inducer)
elicits a colour perception (the concurrent).
17
Such synaesthetic expe-
riences are typically reported by individuals with absolute, reference-
free sensory judgments such as “The sound of the trumpet is scarlet”
or “F is green”.
Synaesthesia is considered as a genuine sensory phenomenon and not
merely a high-level cognitively-mediated (e.g., mnemonic) association
(Ramachandran & Hubbard, 2001). For example, an individual with
number-colour synaesthesia is not just ‘imagining the colour’ nor is s/he
associating it to numbers based on childhood memories. For example, if
several 2’s are scattered among a matrix of randomly placed 5’s, the
global shape formed by the embedded 2’s is very hard to discern; normal
participants take several seconds to nd the shape. However, a gra-
pheme–colour synaesthete might look at it and very quickly see the
global shape as a red triangle or square against a background of green 2’s
(Ramachandran & Hubbard, 2001; though note that only a subset of
synaesthetes has been shown to experience such pop-out phenomena).
Such results show that, at least in certain cases, synaesthesia is a low-
level sensory phenomenon; the induced colour can lead to pop-out
and segregation and only perceptual features processed early in visual
processing can lead to segregation (Beck, 1966; Treisman, 1982).
18
Several potential links between AP and synaesthesia have been
suggested over the last decades (see Carroll & Greenberg, 1961; Glasser,
2021). The most simple and direct link would be to conceiving of AP as a
case of synaesthesia in which the pitch inducer directly triggers a verbal
concurrent; however, the intersubjective agreement regarding the
inducer-concurrent associations seemingly goes against the idiosyn-
cratic nature of synaesthetic matchings. Another possibility would be to
conceive forms of synaesthesia induced by pitch as mediated by AP.
Findings from Itoh et al. (2017) support this idea, demonstrating that the
associations between pitch class and colour in synaesthetes with AP are
mediated by the name of the note (i.e., C, D, E…), so that there turn out
to be two associations: pitch-pitch class (via AP) and pitch class-colour
(via synaesthesia). Alternatively, one could suggest a more indirect
and cognitively mediated link, in which the synaesthesia allows the
perceiver to directly move from pitch to colour and then use colours to
deduce pitches via a deliberate matching between colours and pitch
names. For this latter possibility to be valid, several conditions must
hold, such as that notes a semitone apart must have perceivable differ-
ences in colour; the induced colour percept must be indifferent to
timbre; stored perceptual differences can acquire linguistic labels (Ward
et al., 2006). This phenomenology has anecdotally been supported by a
single-case report of a professional musician with AP who used her tone-
colour synaesthesia to identify the pitch of a tone (H¨
anggi et al., 2008,
see also Bouvet et al., 2014; Haack & Radocy, 1981; and Lebeau et al.,
2020, for reports on single-case, and also Petrovic et al., 2012; Zdzinski
et al., 2019, on chromaesthesia and AP).
The link between synaesthesia and AP might also be established on a
merely statistical basis, with the literature showing that there is a
signicantly higher prevalence of synaesthesia among those individuals
who have been identied as having AP. For instance, Gregersen et al.
(2013) found that out of 768 individuals with AP, 151 (20.1%) reported
being synaesthetes with colour being the most common concurrent.
17
Estimates of the prevalence of music-colour synaesthesia within the syn-
aesthete population vary between studies, but were reported at 41% in a study
by Niccolai et al. (2012). It might not be easy to establish when synaesthesia
appears during human development given that it might take time for in-
dividuals to become aware they are synaesthetes.
18
As observed by Spence and Di Stefano (2023), the link between the inducer
and the concurrent in synaesthesia can be conceived of in terms of “syno-
nymity” or “identity”: Rather than being associated or cognitively-linked, the
inducer and the concurrent are simply part of one and same perceptual expe-
rience. Hence, for a synaesthete, the sound of the trumpet and the colour scarlet
are always co-experienced (though note that some early reports showed that
colours were only sometimes induced by musical sounds; see MacDougal,
1898).
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
9
Moreover, at least according to certain sources, AP may be much less
frequent among the population than synaesthesia (e.g., 0.01–1% vs.
1–4%, respectively, see Levitin & Rogers, 2005 and Simner et al., 2006,
although both values are subject to variability depending on the specic
inclusion/selection criteria). This would be consistent with the fact that
only a fraction of synaesthetes are pitch-name synaesthetes. Finally, and
importantly, results from Gregersen et al. (2013) demonstrated a close
phenotypic and genetic relationship between AP and synaesthesia. That
being said, however, the literature also demonstrates that AP is by no
means necessary for pitch class-colour synaesthesia (Itoh et al., 2017).
The linkage between AP and synaesthesia is further supported by
neurophysiological ndings. H¨
anggi et al. (2008) compared magnetic
resonance images of the brain of a pitch-taste and pitch-colour synaes-
thete with AP and a control group (musicians and non-musicians). The
results highlighted increased volumetric white and grey matter in the
synaesthete’s auditory and gustatory areas, which might be associated
to the interval-taste synaesthesia as well as volumetric white and grey
matter alterations in visual areas, which might represent the neuro-
architectural foundation of the tone-colour synaesthesia (see also Dohn
et al., 2015 for white matter anatomy in individuals with AP). FMRI
studies by Loui et al. (2011, 2012) found enhanced activity in the su-
perior temporal gyrus associated with auditory associations in those
individuals with coloured-music synaesthesia and AP. This led re-
searchers to claim that AP and synaesthesia are “two sides of the same
coin” (Loui et al., 2013), meaning that the same general mechanism of
enhanced sensory activation allegedly feeds into auditory experience in
AP and visual experience in synesthetes.
3.2. Extraordinary memory and AP
In the psychological literature, cases are reported of individuals who
have the extraordinary ability to memorize a huge number of sensory
stimuli and are able to recall these memories even after long time (e.g.,
years). Intriguingly, this ability is often considered as linked to synaes-
thesia (Rothen et al., 2012). Anecdotal reports of this go back to the case
of Solomon Shereshevskii studied by Luria (1968), who famously said
that his memory “had no distinct limits […] there was no limit either to
the capacity of Shereshevskii’s memory or the durability of the traces
retained” (p. 11). For instance, he could recall long meaningless lists of
nonsense syllables and written nonsense equations both immediately
and after 4 and 8 years or remember matrices of 50 digits after only a
few minutes of inspection. Moreover, he was able to effortlessly recall
them when retested 15 or 16 years later. Shereshevskii had multiple
forms of synaesthesia (e.g., sound-colour synaesthesia, phoneme-colour
synaesthesia, phoneme-taste synaesthesia); however, the extent to
which his memory ability was attributable to his synaesthesia is unclear.
Another case is reported of a man who has memorized over 6000
books and has encyclopaedic knowledge of several disciplines, such as
geography, literature, history, sports, and music. He was able to name all
the US area codes and major city zip codes. He also has the ability to read
extremely rapidly, simultaneously scanning one page with the left eye
and the other page with the right eye (Peek & Hanson, 2007).
Intriguingly, similar extraordinary mnemonic abilities, occasionally
also referred to as “savant syndrome” (Treffert, 2009), have been related
to AP (Birbaumer, 1999; Snyder & Mitchell, 1999). Both AP and eidetic
memory have been often considered as fast, low-level, sensory-rooted
operations. Commentators have occasionally described the experience
of musical savants with AP in terms of the direct access to lower levels of
“raw” auditory information which are normally integrated into holistic
information content in normal perceivers (Heaton et al., 1998; Miller,
1989). However, cognitive mediation must be recognized in those
extraordinary mnemonic abilities that require some form of mathe-
matical or computational skills.
Considering all the abilities in the human repertoire, it might be
interesting to observe that music is one of those extraordinary skills that
are most consistently present among savants, with AP being one of its
most prevalent manifestations. It is interesting as well to note that un-
usual sensory discrimination in smell, touch, or vision including syn-
aesthesia are among the other skills that have been reported, although
less often, together with a prodigious facility for language. Last but not
least, these special skills are always accompanied by prodigious memory
abilities (Treffert, 2009). Conversely, typical synaesthetes have moder-
ately enhanced long-term episodic memory and, to a lesser extent, also
short-term, working memory (Rothen et al., 2012; Ward et al., 2019).
Mottron et al. (2009) proposed that many savant abilities involve a
one-to-one mapping process between two isomorphic series of elements,
a mapping between different codes involving the detection of structural
similarity between the two series of units (see Di Stefano & Spence,
2023, on issues related to similarity across the senses). Importantly, the
mastering of these mappings is implicit, both in the way in which they
are learned and in the frequent difculty or impossibility that savants
have in verbalizing the strategies that they use to produce answers
relying on these mappings. According to this view, therefore, AP could
be explained in terms of the mapping between two discretized di-
mensions, pitch labels and pitches of the chromatic scale.
Such a one-to-one mapping ability might be considered as a conse-
quence of another ability that is often associated with savants, namely,
enhanced pattern detection, which allows for the stabilizing of associ-
ations between labels and precise values within continuous dimensions
(e.g., frequency; Mottron et al., 2009; Treffert, 2009). For most savant
abilities, the equivalent ability in normal individuals is only poorly or
rarely, if at all, represented; this may be because one series of repre-
sentations cannot be anchored on the other, as in the example of AP.
3.3. Interim summary
The comparison between AP, extraordinary memory, and synaes-
thesia has evidenced some interesting similarities and potential links
between these rare phenomena. First, all these abilities seem to be
automatically executed by the participant, without any cognitive effort.
Such phenomenology might suggest describing the perception of AP in
terms of pitch-label couples that form unique percepts. Just like the
colour and shape of Lego blocks, individuals with AP would perceive an
auditory-verbal unity when perceiving a tone, such as ‘440 Hz-A’.
19
Second, the key role played by associative mechanisms mediated by
memory has been highlighted: in all cases, the subjects seem to be able
to manifest their extraordinary skill thanks to an implicit or explicit
association between stimuli from different domains, such as numbers
and colours, pitch and labels, or calendar dates and days of the week.
However, and interestingly, some associations are more easily recalled
than others, with some preferred sensory directions emerging clearly in
synaesthetes and those individuals with AP, namely, auditory-visual, for
the former, and auditory-verbal/semantic for the latter (see Fig. 3 for a
comparison between the perception of a musical note in individuals
without AP, with AP and in pitch-colour synaesthetes).
Some differences emerge when it comes to the innate or acquired
nature of these abilities. Although musical training is not sufcient in
19
However, different from the simultaneous perception of the colour and
shape of blocks, in AP the information related to pitch name is sensorily absent.
Thus, it might be more properly considered as a case of amodal completion, that
is, an occurrence of perceptual completion in which the observer integrates the
information to generate a perceptual unity (see, e.g., Gerbino, 2020 and Spence
& Di Stefano, 2024, for a recent review). In the case of AP, the subject would be
completing the lacking verbal/semantic information based on the available
auditory information (like when by hearing the bark of a dog one recognizes the
breed). If this is a reliable description of how AP perception works, it further
supports the role of associative learning.
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
10
itself, it is clear from the literature that AP needs musical training to
develop. Something similar can be said of those individuals with
extraordinary mnemonic abilities, who must have been exposed to the
information they demonstrate to recall with accuracy and precision even
after long time. In contrast, synaesthetes do not seem to have gone
through any explicit form of learning that led to the acquisition of
synaesthetic experiences.
Finally, and intriguingly, none of these abilities seem to have any
biological value or, at the very least, it is unclear how they represent an
advantage for the rare individuals who are endowed with them. While
each of them might facilitate individuals in specic tasks, such as the
memorization of a sequence of visual stimuli or the transcription of
melodies, these tasks are seemingly unrelated to survival needs and do
not broadly affect human life as one would expect from sensory abilities
which have a clear biological value (e.g., smelling spoiled food). Addi-
tionally, while synaesthesia is more prevalent in females, “savant syn-
drome” affects more males than females. Somewhat surprisingly, the
same sex ratio is reported for both phenomena, 6:1 (Baron-Cohen et al.,
1996; Treffert, 2009) while, to our knowledge, no study found any
gender differences in the prevalence of AP, which might suggest that the
ability is equally present in males and females.
To summarize, despite some prominent and intriguing similarities in
the phenomenology of synaesthesia, eidetic memory, and AP, the
automatic, sensory, intersubjective, and consensual nature of AP judg-
ments seemingly makes such an ability unique with respect to both
pitch-induced forms of synaesthesia (that are idiosyncratic) and
extraordinary mnemonic abilities (that appear to be conscious rather
than automatic). We now move on to examining a more common
occurrence of absolute sensory judgments, namely colour perception.
3.4. Colour perception and AP perception
Inuential scholars have often highlighted the parallel between AP
perception and colour perception (e.g., Deutsch, 2002; Lewis, 1939).
The analogy between pitch and colour perception was evoked very early
in the literature on AP as an attempt to provide an intuitive explanation
for a very rare perceptual phenomenon through a common one. Lewis
(1939) observed: “Pitch arises as an attribute of auditory experience
when the ear is stimulated in appropriate ways, just as color arises as an
attribute of visual experience when the eye is appropriately stimulated”
(p. 121) (see also Caivano, 1994). Based on Stevens’ (1957) classica-
tion of perceptual dimensions, an analogy exists between auditory pitch
and hue both considered as metathetic sensory dimensions (as well as
both being circular dimensions; Spence & Di Stefano, 2023).
20
Here, we
delve deeper into the comparison between colour perception and AP
perception, drawing attention to a few important aspects that limit the
validity of such comparison, thus supporting the uniqueness of AP in the
domain of sensory perception.
First, different physiological mechanisms underly colour and pitch
perception. Information about colour is separated into discrete streams
by cones in the retina (Kolb, 2003), and remains separated up to the
level of the cortex, thus allowing the human visual system to categorize
colours (Siuda-Krzywicka et al., 2019; Zeki, 1993). In contrast, the co-
chlea and peripheral auditory system processes the frequency of sounds
continuously between about 20 Hz and 20 KHz thus apparently pre-
venting the discrete mapping between excitation patterns and percepts
(Evans, 1992; Julesz & Hirsh, 1972; Warren, 2013).
21
Moreover, much
of what we call music perception deals with the combination of different
tones simultaneously perceived (i.e., harmony); this is not the case for
colours, which are typically perceived as discretized entities.
22
There-
fore, the fact that some individuals can categorize pitches into discrete
Fig. 3. Conceptual representation of the perception of a musical tone by normal perceivers (A), individuals with AP (B), and pitch-colour synesthetes with AP (C). All
human gures designed by studiogstock/Freepik.
20
Note that metathetic dimensions obey a well-structured organization
without necessarily having a ‘more than’ or ‘less than’ end. In contrast, pro-
thetic dimensions are quantitative perceptual continua (i.e., having to do with
how much) with ratio properties with a clear ‘more than’ and ‘less than’ end.
Examples of these dimensions are loudness, brightness, visual lightness,
heaviness, duration, and roughness (Stevens, 1957, 1971).
21
If this holds true for the way in which auditory information is processed,
one must acknowledge that in musical practice, a small range of frequencies
surrounding one specic frequency is often accepted as corresponding to the
particular musical pitch. This is seemingly similar to what happens with col-
ours, leaving the question on the many/one-to-one mapping of colours and
pitch open.
22
See Kubovy and Van Valkenburg (2001) and Kubovy and Schutz (2010) for
a reection on the duality of vision and audition and of their underlying
mechanisms (e.g., colour constancy in vision).
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
11
categories requires an explanation of what is different about these in-
dividuals in terms of their perceptual and/or neural architecture (see
also Ross et al., 2005).
Moreover, the variability in the way in which AP impacts tone
perception might make the comparison between AP and hue perception
only partially valid. For example, studies have shown that some in-
dividuals with AP can identify the label of tones produced by only one
particular instrument, thus suggesting that other factors, such as timbre,
might impact AP perception (Reymore & Hansen, 2020). Other in-
dividuals, meanwhile, have AP for only a single tone which allegedly
acts as an internal referent for the calculation of other pitches (this case
is often referred to as ‘quasi-AP’); what is more, these individuals typi-
cally have slower reactions in discrimination/perception tasks (e.g.,
Bachem, 1937; Levitin & Rogers, 2005, and Ward, 1999, for reviews).
23
Taken together, therefore, these studies demonstrate that AP is not
exclusively dependent on pitch.
Beyond psychophysical and physiological differences, there are some
fundamental differences in the way in which AP and colour labels
emerge in humans. While it is well-established that the development of
both abilities needs repetitive exposure to the perceptual stimuli and
memory (see Section 2 for AP and Pitchford & Mullen, 2006, for the
acquisition of colour terms), it should also be pointed out that the
mnemonic skills required for storing the matches between colour hues
and colour labels seem much less demanding and more common than
the mnemonic ability required for creating consistent pitch-labels as-
sociations. This is reected by the fact that most infants develop the
ability to name colours between the age of 3 and 6 years (at least with a
similar accuracy of identication of individuals with AP in labelling
pitches), with most children associating at least the basic colours and
their names correctly and consistently after 4–5 years of age (Bornstein,
1985). In contrast, AP needs more time to be fully developed (between 5
and 9 years of age, Levitin & Rogers, 2005; Ward, 1999). Moreover,
while only a small fraction of children exposed to musical stimuli
develop AP, the large majority of (typically developing) children end up
in mastering colour names within a few years. This might be even more
surprising, given that the children who receive musical training are
likely exposed longer to pitch labelling than to colour labelling and,
nevertheless, they acquire colours names rst.
One explanation for the developmental delay, the additional effort,
and the relatively higher training of AP, is that colours are environ-
mentally frequent, if not ubiquitous, features of objects. In contrast, very
few objects have pitch as one of their perceptual features. Children
interact every day with coloured objects and use colour names when
playing; but they rarely, if ever, use pitch labels. Moreover, colour is a
highly salient perceptual dimension for children which allows them to
classify and sort objects they interact with; in contrast, children will
hardly classify objects, not even musical instruments, according to the
exact pitch they produce. In contrast, one might observe that pitch is a
less perceptually salient feature of objects, and likely even of sounding
objects. Thus, pitch processing, not to say AP, likely needs a stronger
contribution of cognitive components which might develop both later
and more slowly. Finally, and more generally, it is also worth noting that
humans are visually dominant creatures, with larger neural resources in
the sensory cortex devoted to the processing of sight rather than sound
(e.g., Gallace et al., 2012; Hutmacher, 2019).
The different phenomenal qualities of pitch and hue might also play a
role here. While categorizing the hue of colours is quite intuitive (e.g.,
‘Red’ or ‘Blue’), perceiving pitch chroma as a salient and consistent
perceptual category of sounds (e.g., ‘C’ or ‘D’) seems much more difcult
for those individuals without AP. Thus, for instance, it would make sense
to make intramodal comparison, by asking, for example, whether red is
more similar to brown or black, but it would make much less sense to ask
whether C is more similar to A or F# (see Di Stefano & Spence, 2023, on
issues arising from perceptual similarity).
24
To summarize, the parallel between colour perception and AP
perception could not be taken literally and could not help in under-
standing the nature of AP perception. Although colour and pitch
perception share several surface properties, at deeper examination
crucial differences emerge that make the comparison inadequate. This
provides further support to the idea that AP represents a unique kind of
absolute sensory judgment in humans.
4. Conclusions
4.1. Main ndings
The evidence reviewed here provides insights into the genetic and
ethnic factors inuencing the development of AP, with an emphasis on
familial studies, ethnic clusters, and the role of early music training (e.g.,
Gregersen et al., 1999; Gregersen et al., 1999, Gregersen et al., 2000;
Prota et al., 1988). Familial aggregation studies suggest a higher
likelihood of AP in siblings of AP possessors, with the age of onset,
combined with genetic factors and early practice, considered as a factor
strongly inuencing pitch-naming ability. Ethnic clusters for AP are
observed, with higher rates among Asian students compared to Cauca-
sian students, and signicant differences in prevalence across countries
(Miyazaki, 2004a, 2004b; Miyazaki et al., 2018). Early exposure to tonal
languages does not fully explain the higher prevalence among Asians,
with the Suzuki method and other pedagogical traditions (xed pitch
training) likely contributing to ethnic differences.
The neuroscientic literature has revealed the intricate neural
mechanisms associated with AP perception, emphasizing the involve-
ment of multiple brain regions and potential variations in processing
strategies among individuals with AP skills. In particular, studies suggest
a functional pathway involving bilateral PT and the left posterior DLFC,
forming a network implicated in AP ability (e.g., Bermudez & Zatorre,
2005; Ohnishi et al., 2001; Schulze et al., 2009; Wengenroth et al., 2014;
Wilson et al., 2009; Zatorre et al., 1998). The DLFC, implicated in those
tasks that require working memory, likely mediates AP musicians’
ability to associate pitch with verbal labels. The PT, located in the su-
perior temporal gyrus, plays a vital role in pitch processing. Positive
correlations between left PT activation and AP prociency are observed.
Neuroanatomical studies show stronger left surface/volume asymmetry
in PT among AP musicians, associated with increased AP accuracy
(Benner et al., 2023). Early ndings on right-hemispheric domination in
AP processing need further empirical conrmation, given some
controversial ndings.
The behavioural literature shows that AP emerges early in develop-
ment, typically between 3 and 6 years, and is strongly correlated with
musical education (Bachem, 1937; Levitin & Rogers, 2005; Miyazaki,
2004a; Ward, 1999). AP is considered an automatic perceptual exper-
tise, effortless for those who possess it, with individuals often unaware of
its exact functioning. While it can persist throughout life, traumatic
events or certain drugs may temporarily affect it (e.g., carbamazepine,
see Braun & Chaloupka, 2005). AP manifests as a spectrum of skills,
23
For example, those individuals with quasi-AP typically take more time to
identify the key that has been struck on a piano keyboard than those with AP
(Bachem, 1937).
24
It is perhaps worth going back to Helmholtz regarding this point. The early
psychophysicist once wrote that: “The distinctions among sensations which
belong to different modalities, such as the differences among blue, warm,
sweet, and high-pitched, are so fundamental as to exclude any possible tran-
sition from one modality to another and any relationship of greater or less
similarity. For example, one cannot ask whether sweet is more like red or more
like blue. Comparisons are possible only within each modality; we can cross
over from blue through violet and carmine to scarlet, for example, and we can
say that yellow is more like orange than like blue!” (Von Helmholtz, 1878/
1971, p. 77).
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
12
varying in accuracy, response time, and means of identication. The
primary manifestation is immediate pitch naming, with accuracy
ranging between 70% and 99% (Takeuchi & Hulse, 1993).
Surprisingly, AP possessors and non-possessors exhibit equivalent
acuity for pitch differences (Levitin, 2004). While often seen as a sign of
musical talent, AP may negatively impact some musical tasks involving
pitch transpositions (e.g., Miyazaki, 2004b; Revesz, 1953; Ward, 1999).
Cases of individuals who can identify the frequency but not the name of
the pitch suggest that rened perceptual skills alone are insufcient for
AP, challenging the idea of a direct mapping of physical frequencies onto
pitch categories. The complexity of the phenomenon is underscored by
the nuanced differences in performance with specic timbres, notes, or
frequency ranges.
The prevalence of AP has been studied in relation to neuro-
developmental disorders such as ASD and Williams syndrome (Bonnel
et al., 2003; Heaton, 2003; Heaton et al., 1998; Lenhoff et al., 2001;
Masataka, 2017; Meilleur et al., 2015). Individuals with ASD often
exhibit heightened pitch discrimination and memory for melody, but
may struggle with vocal imitation tasks. In Williams syndrome, studies
yield conicting results, with some indicating near-ceiling levels of AP,
while others suggest low performance compared to controls. Finally,
blind individuals, particularly those who received musical training,
show a higher incidence of AP, with neural correlates differing from
sighted AP individuals (Hamilton et al., 2004; Gaab et al. 2006; Welch,
1988).
4.2. Is AP a unique kind of absolute sensory judgment in humans?
Returning, then, to the main question of this paper, we can answer by
observing that AP is a unique kind of absolute sensory judgment in
humans: individuals with AP can recall the names of pitches in a quick,
automatic, consensual, and, apparently, effortless manner, without the
need of a reference. We have supported this claim by comparing, for the
rst time, AP with phenomenologically similar rare and common phe-
nomena in which perceivers formulate absolute sensory judgments, such
as synaesthesia and colour perception. The idiosyncratic nature of the
inducer-concurrent matchings in synaesthesia is incompatible with the
consensual associations between auditory-verbal stimuli in AP per-
ceivers. Moreover, from a developmental perspective, there is no
learning period associated to synaesthesia and people typically report
having it from as early as a child can remember, while most people with
AP date it back to the years of musical training. At the same time, the
psychophysical, physiological, and perceptual differences between
colour perception and AP prevent us from considering these two oc-
currences of reference-free sensory judgments as similar.
25
Thus, in
contrast with extraordinary memory, synaesthesia, and colour percep-
tion, we can conclude by afrming that AP emerges as the only ability
that is, at the same time, sensory, automatic, and based on non-
idiosyncratic mappings (see Table 2).
The uniqueness of AP is apparent even when contrasted with a
related perceptual phenomenon—absolute tempo. Conceived of as the
rhythmic counterpart of AP, absolute tempo involves the capability to
recognize or recall the tempo of musical compositions without external
cues. Despite the extensive scientic interest in AP over the past century,
resulting in hundreds of published papers on the subject, the equivalent
rhythmic skill has received limited attention. Only one study, conducted
by Gratton, Brandimonte, & Bruno (2016), has systematically explored
absolute tempo, highlighting a signicant gap in research compared to
the comprehensive investigation of AP.
An apparently overlooked aspect in the literature is the directionality
of AP. Most tests used to assess AP expose individuals to auditory stimuli
rst (often isolated pitches) asking them to verbally identify or repro-
duce them on a musical instrument. This leaves at least partially unclear
whether AP has a privileged direction, namely, from auditory to verbal/
semantic. Based on the reviewed literature, it seems unlikely that in-
dividuals with AP hear a tone when presented with the name of the
pitch, for at least two reasons. First, because the pitch chroma does not
necessarily identify an octave, and octave errors are frequent in AP
perception. Thus, while linking the tone to the label should be unam-
biguous, the reverse path would admit different answers. For example,
the label “A” might be correctly associated with 220 Hz, 440 Hz; 880 Hz.
Second, because an auditory image triggered by a pitch label would
probably classify as a form of synaesthesia, namely, the association
between the semantic inducer and the auditory concurrent.
26
4.3. Open issues
The role of learning and language in mediating AP perception re-
mains somewhat obscure. The literature has distinguished between
musical AP and general AP, demonstrating that AP-like memory for
pitch is widespread among those individuals who do not possess AP
(Halpern, 1989; Levitin, 1994; Schellenberg & Trehub, 2003; Terhardt &
Seewann, 1983; Terhardt & Ward, 1982). Why, then, should AP-like
pitch-label matching be so rare among individuals? The reason behind
the inability to name pitch class cannot be the mere ignorance of tone
names, because a person without this knowledge could presumably in-
vent his/her own names for the few tones that they are able to distin-
guish. However, as observed by one of the reviewers of this paper, the
fact that listeners could invent their own names does not imply that they
would do so in any particular setting. It can be argued that labelling is a
process that is either cognitively or perceptually more demanding than
merely associating a percept with a tag, and that language/verbalization
plays a constitutive role in AP perception.
The reviewed evidence converged on the suggestion that AP does not
appear to confer any evident advantage to those individuals who possess
it, even in the case of musicians (Levitin, 2004; Miyazaki, 2004b).
However, given the abundance of studies highlighting the existence of a
genetic component of AP (e.g., Gregersen et al., 1999, 2000), an
intriguing question emerges regarding the utility, or biological value, of
AP. In other words, one must ask what such putative genes would code
for, and what the possible evolutionary value might be.
In contrast with the ability to perceive other acoustic features, such
as timbre (e.g., Di Stefano & Spence, 2022, on roughness) or harmony (e.
Table 2
A comparison among AP, extraordinary memory, synaesthesia, and colour
perception.
Extraordinary
memory
Synaesthesia Colour
perception
Absolute
pitch
Dichotomous/
Continuous
Dichotomous Dichotomous Continuous Continuous
Cognitive/
Sensory
Cognitive &
sensory
Sensory Cognitive &
sensory
Sensory
Automatic/
Conscious
Conscious Automatic Conscious Automatic
Evolutionary
benet
None None Yes None
Idiosyncratic
mapping
No Yes No No
Learnability No No Yes To some
extent
Categorical Yes Yes (?) Yes Yes
Language-
mediation
Yes No Yes Yes
25
Regarding the distinction between musical AP and general AP, our con-
clusions explicitly refer to “musical” AP and “general” AP as categorically
distinct perceptual phenomena.
26
This case would be even more problematic given the unidirectional nature
of synaesthesia.
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
13
g., Bowling & Purves, 2015, and Di Stefano et al., 2022, on consonance),
pitch labelling does not seem to play any evolutionary role.
27
Thus, it
has been suggested that AP might be a maladaptive trait, that is, an
unfortunate side effect of early and intense musical training (Weisman
et al., 2006). However, if this were to be the case, one would expect that
natural selection should progressively reduce its occurrence in the
population.
Considering AP as a maladaptive trait would partially address an
argument based on the similarity between colour perception and pitch
perception. The argument is as follows: we are exposed to colours and
their names since birth, and this exposure leads all healthy individuals to
master colour names in few years, with the exception of the rare in-
dividuals affected by colour anomia.
28
Similarly, with many people
studying music across the world, why do most people have “pitch
anomia”? As Diana Deutsch (2006, p. 11) puts it: “So the real mystery of
AP is not why some people possess this ability, but instead why it is so
rare?”
29
Besides stressing the biological irrelevance of AP as a mal-
adaptive trait, contrasted with the allegedly biologically useful ability of
mastering colour names (Jacobs, 2009; Matthen, 1988), one might also
underscore that, although the prevalence of AP in the population is very
low, it increases a lot when we narrow down the sample to musicians
only. However, one has to acknowledge that, despite the consistent
exposure to pitch naming since a very young age, most musicians do not
develop AP, while most of them develop rened relative pitch ability.
The idea of AP as a maladaptive trait might receive support from the
speculative idea that most, if not all, infants possess AP at birth, but such
an ability is inhibited in the rst year with the onset of language
acquisition (Saffran, 2003; Saffran & Griepentrog, 2001; see also Levitin,
1994). According to this hypothesis, also known as the “savant’s hy-
pothesis”, the loss of AP might be explained in biological or cognitive
terms, given that a common strategy at work in the human brain is
reducing the complexity of information to improve efciency by
creating higher-level concepts which discard low-level detail and reduce
the number of items one has to manipulate. In this view, processing pitch
in an absolute way, instead of relatively, reduces the generalizability of
pitch perception based, for example, on octave similarity and trans-
positions, thus resulting in a less efcient and more demanding pro-
cess.
30
Thus, most perceivers might lose such an ability to enhance their
abilities to process pitch. In line with the savant’s hypothesis, Bosso-
maier and Snyder (2004) have argued that AP is latent within everyone
and that it can be switched on by turning off those parts of the brain that
are responsible for the inhibition. However, this claim did not receive
empirical conrmation, together with a similar hypothesis about the
origins of synaesthesia which lacks empirical support (Deroy & Spence,
2013).
Finally, the above reection leads to a more general observation on
the way the issue of AP (as well as many other rare perceptual skills) is
approached, namely the idea that the ability is either innate (i.e., bio-
logically or genetically determined) or learned/acquired (i.e., developed
thanks to contextual and cultural factors). We argue that such a
dichotomic alternative is misconceived and misleading, given that most
fundamental abilities that are typically considered as innate have to be
eventually learned. Thus, it is probably better to reshape the conceptual
approach and focus on the nature of the learning trajectory: when the
acquisition of a skill is successful and easy for most individuals, the skill
might be considered as more hardwired into the biology of human be-
ings (and thus ‘innate’); when the mastering of a skill is hard to achieve,
and the learning trajectory highly variable across individuals and often
unsuccessful, that ability is not innate, or “less innate”/“acquired”, and
hence likely determined by individual factors. Examples of the former
abilities can be walking or speaking a language, while examples of the
latter can be mastering painting or violin playing (see Table 2 for a
summarizing comparison between AP, extraordinary memory, and
synaesthesia).
4.4. Future directions
A rst line of investigation would provide further insights into the
perceptual aspects that characterize AP, particularly referring to the
directionality of AP. Experiments might be conducted to assess whether
individuals with AP hear a tone when presented with the name of the
pitch or read the note on the score. Similarly, one might also test
whether the corresponding auditory pitch is evoked by the mere sight of
keys being pressed on a piano or any other way of producing musical
tones with instruments. This could be especially tested in piano or
instrumental pitch possessors. In all of these experiments, it would be
interesting to know more about the timbral quality of the pitch that is
evoked (if any) by abstract referents (e.g., notes on the score or pitch
labels) or instrument-related ones (e.g., piano keys or guitar frets).
Should empirical ndings conrm such a reverse sensory path among AP
listeners, or a subset of them, it would be difcult to distinguish such
sensory experiences from synaesthesia, apart from the fact that AP
experience is intersubjective and non-idiosyncratic (i.e., the verbal label
triggered by the same pitch is consistent across individuals).
Second, given the evidence showing that crossmodal correspon-
dences involving auditory pitch are mostly based on relative pitch
(Spence, 2019), it would most certainly be interesting in future research
to investigate how those individuals with AP perform in those tasks on
crossmodal correspondences involving auditory pitch (such as, for
example, Brunetti et al.’s, 2018, speeded classication task). One would
expect those listeners to be more accurate, fast, and consistent when
tasks require auditory discrimination abilities.
Third, it would be interesting to assess whether such an absolute
perception of auditory parameters exists beyond the domain of pitch.
For instance, experiments might be carried out to examine the percep-
tion of absolute loudness or absolute tempo (see Gratton et al., 2016).
Different approaches might be taken in this case, such as enrolling pri-
marily those subjects who demonstrated extraordinary ability in AP
perception or rather musicians specically trained in rhythmic skills (e.
g., drummers, percussionists). Similar ndings might also shed light on
the role of learning in the acquisition of AP-like skills, as neither loud-
ness nor tempo are normally taught in the same manner as pitch (i.e.,
involving the association of verbal labels with metronome/loudness
values). However, given that tonality and harmony are xed parameters
compared to tempo/loudness in music composition and production (i.e.,
the tempo of Beethoven’s Overture “Leonore” could vary across different
interpretations, but its harmonic and melodic structure remains unal-
tered), one could be perplexed about the musical relevance or utility of
such abilities.
Beyond the auditory domain, one might wonder whether, given the
similar nature of vibratory phenomena in touch and audition, perceivers
exist who exhibit a tactile equivalent of AP. Experiments designed in an
attempt to investigate AP in touch should carefully consider the different
sensation thresholds of tactile receptors in the human body.
Finally, the development of technological devices that can provide
normal perceivers with AP-like experience is also an intriguing area for
future development. Along such lines, it is worth mentioning the recent
27
AP plays no role in the authoritative reviews recently published in Behav-
ioural and Brain Sciences about the origins and functions of music (Mehr et al.,
2021; Savage et al., 2021).
28
People with colour anomia can recognize that two objects are of the same
colour, and can discriminate between different colours, but simply cannot label
them.
29
A similar question is raised by Levitin (1994): “The proper question might
not be the one often asked, ‘Why do so few people have AP’ but rather, ‘Why
doesn’t everybody?’” (p. 414). Levitin grounds his question on properties of the
auditory system: given that cells that respond to particular frequency bands are
found at every level of the auditory system, information about the AP of a
stimulus is therefore potentially available throughout the auditory system.
30
Notably, pitch processing in an absolute way is more frequent in non-human
animals than in humans (Hoeschele, 2017).
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
14
conference paper by Oka and Kurihara (2022) in which the authors
present a multimodal augmented reality system that allows normal
perceivers to have auditory and visual feedback of note names that can
simulate the experience of individuals with AP. Sensory substitution
devices might also translate auditory pitch into colours and thus provide
absolute (visual) perception of auditory pitch (see Spence & Di Stefano,
2023, on translating between audition and vision). Similar devices
might be used for training purposes, especially with kids in the AP
“critical period”.
CRediT authorship contribution statement
Nicola Di Stefano: Writing – review & editing, Writing – original
draft, Methodology, Conceptualization. Charles Spence: Writing – re-
view & editing, Supervision, Conceptualization.
Declaration of competing interest
None.
Data availability
No data was used for the research described in the article.
Appendix A. Supplementary data
Supplementary data to this article can be found online at https://doi.
org/10.1016/j.cognition.2024.105805.
References
Bachem, A. (1937). Various types of absolute pitch. The Journal of the Acoustical Society of
America, 9(2), 146–151. https://doi.org/10.1121/1.1915919
Bachem, A. (1940). The genesis of absolute pitch. The Journal of the Acoustical Society of
America, 11, 434–439. https://doi.org/10.1121/1.1916056
Bachem, A. (1954). Time factors in relative and absolute pitch determination. The
Journal of the Acoustical Society of America, 26(5), 751–753.
Bachem, A. (1955). Absolute pitch. The Journal of the Acoustical Society of America, 27(6),
1180–1185.
Baharloo, S., Johnston, P. A., Gitschier, J., & Freimer, N. B. (1998). Absolute pitch: An
approach for identication of genetic and nongenetic components. The American
Journal of Human Genetics, 62(2), 224–231.
Baharloo, S., Risch, N., Gitschier, J., & Freimer, N. B. (2000). Familial aggregation of
absolute pitch. The American Journal of Human Genetics, 67(3), 755–758.
Bahr, N., Christensen, C. A., & Bahr, M. (2005). Diversity of accuracy proles for absolute
pitch recognition. Psychology of Music, 33(1), 58–93.
Baird, J. W. (1917). Memory for absolute pitch. In E. C. Sanford (Ed.), Studies in
psychology, Titchener commemorative volume (pp. 43–78). Worcester, MA: Wilson.
Bairnsfather, J. E., Ull´
en, F., Osborne, M. S., Wilson, S. J., & Mosing, M. A. (2022).
Investigating the relationship between childhood music practice and pitch-naming
ability in professional musicians and a population-based twin sample. Twin Research
and Human Genetics, 25(3), 140–148.
Baron-Cohen, S., Burt, L., Smith-Laittan, F., Harrison, J., & Bolton, P. (1996).
Synaesthesia: Prevalence and familiality. Perception, 25(9), 1073–1079. https://doi.
org/10.1068/p251073
Beck, J. (1966). Effect of orientation and of shape similarity on perceptual grouping.
Perception & Psychophysics, 1(5), 300–302.
Benner, J., Reinhardt, J., Christiner, M., Wengenroth, M., Stippich, C., Schneider, P., &
Blatow, M. (2023). Temporal hierarchy of cortical responses reects core-belt-
parabelt organization of auditory cortex in musicians. Cerebral Cortex, 33(11),
7044–7060.
Bermudez, P., & Zatorre, R. J. (2005). Conditional associative memory for musical
stimuli in nonmusicians: Implications for absolute pitch. Journal of Neuroscience, 25
(34), 7718–7723.
Berti, S., & Roeber, U. (2013). Encoding into visual working memory: Event-related brain
potentials reect automatic processing of seemingly redundant information.
Neuroscience Journal, 2013.
Birbaumer, N. (1999). Rain Man’s revelations. Nature, 399(6733), 211–212.
Blumenfeld, R. S., & Ranganath, C. (2006). Dorsolateral prefrontal cortex promotes long-
term memory formation through its role in working memory organization. Journal of
Neuroscience, 26(3), 916–925.
Boggs, L. P. (1907). Studies in absolute pitch. American Journal of Psychology, 18,
194–205.
Bonnel, A., McAdams, S., Smith, B., Berthiaume, C., Bertone, A., Ciocca, V., …
Mottron, L. (2010). Enhanced pure-tone pitch discrimination among persons with
autism but not Asperger syndrome. Neuropsychologia, 48(9), 2465–2475.
Bonnel, A., Mottron, L., Peretz, I., Trudel, M., Gallun, E., & Bonnel, A. M. (2003).
Enhanced pitch sensitivity in individuals with autism: A signal detection analysis.
Journal of Cognitive Neuroscience, 15(2), 226–235.
Bornstein, M. H. (1985). On the development of color naming in young children: Data
and theory. Brain and Language, 26(1), 72–93.
Bossomaier, T., & Snyder, A. (2004). Absolute pitch accessible to everyone by turning off
part of the brain? Organised Sound, 9(2), 181–189.
Bouvet, L., Donnadieu, S., Valdois, S., Caron, C., Dawson, M., & Mottron, L. (2014).
Veridical mapping in savant abilities, absolute pitch, and synesthesia: an autism case
study. Frontiers in Psychology, 5, 106.
Bowling, D. L., & Purves, D. (2015). A biological rationale for musical consonance.
Proceedings of the National Academy of Sciences, 112(36), 11155–11160.
Braun, M., & Chaloupka, V. (2005). Carbamazepine induced pitch shift and octave space
representation. Hearing research, 210(1–2), 85–92.
Brenton, J. N., Devries, S. P., Barton, C., Minnich, H., & Sokol, D. K. (2008). Absolute
pitch in a four-year-old boy with autism. Pediatric Neurology, 39(2), 137–138.
Brunetti, R., Indraccolo, A., Del Gatto, C., Spence, C., & Santangelo, V. (2018). Are
crossmodal correspondences relative or absolute? Sequential effects on speeded
classication. Attention, Perception, & Psychophysics, 80, 527–534.
Caivano, J. L. (1994). Color and sound: Physical and psychophysical relations. Color
Research & Application, 19(2), 126–133.
Carden, J., & Cline, T. (2019). Absolute pitch: Myths, evidence and relevance to music
education and performance. Psychology of Music, 47(6), 890–901.
Carroll, J. B. (1975). Speed and accuracy of absolute pitch judgments: Some latter-day
results. ETS Research Bulletin Series, i–71.
Carroll, J. B., & Greenberg, J. H. (1961). Two cases of synesthesia for color and musical
tonality associated with absolute pitch ability. Perceptual and Motor Skills, 13, 48.
https://doi.org/10.2466/pms.1961.13.1.48
Chavarria-Soley, G. (2016). Absolute pitch in Costa Rica: Distribution of pitch
identication ability and implications for its genetic basis. The Journal of the
Acoustical Society of America, 140(2), 891–897.
Chin, C. S. (2003). The development of absolute pitch: A theory concerning the roles of
music training at an early developmental age and individual cognitive style.
Psychology of Music, 31(2), 155–171.
Clark, D. L., Boutros, N. N., & Mendez, M. F. (2010). The brain and behavior: An
introduction to behavioral neuroanatomy. Cambridge, UK: Cambridge University Press.
Crummer, G. C., Walton, J. P., Wayman, J. W., Hantz, E. C., & Frisina, R. D. (1994).
Neural processing of musical timbre by musicians, nonmusicians, and musicians
possessing absolute pitch. The Journal of the Acoustical Society of America, 95(5),
2720–2727.
Cytowic, R. E. (1997). Synaesthesia: Phenomenology and neuropsychology—A review of
current knowledge. In S. Baron-Cohen, & J. E. Harrison (Eds.), Synaesthesia: Classic
and contemporary readings (pp. 17–39). Oxford, UK: Blackwell Publishing.
Deroy, O., & Spence, C. (2013). Are we all born synaesthetic? Examining the neonatal
synaesthesia hypothesis. Neuroscience & Biobehavioral Reviews, 37, 1240–1253.
https://doi.org/10.1016/j.neubiorev.2013.04.001
Deutsch, D. (2002). The puzzle of absolute pitch. Current Directions in Psychological
Science, 11(6), 200–204.
Deutsch, D. (2006). The enigma of absolute pitch. Acoustics Today, 2, 11–19.
DePape, A.M.R., Hall, G.B., Tillmann, B., & Trainor, L.J. (2012). Auditory processing in
high-functioning adolescents with autism spectrum disorder. Plos One 7(9): e44084.
https://doi.org/10.1371/journal.pone.0044084.
Deutsch, D. (2013). Absolute pitch. In D. Deutsch (Ed.), The psychology of music (pp.
141–182). Amsterdam, NL: Elsevier.
Deutsch, D., Dooley, K., Henthorn, T., & Head, B. (2009). Absolute pitch among students
in an American music conservatory: Association with tone language uency. The
Journal of the Acoustical Society of America, 125(4), 2398–2403.
Deutsch, E. O. (1990). Mozart: A documentary biography (3rd ed.). London, UK: Simon and
Schuster.
Di Stefano, N., & Spence, C. (2022). Roughness perception: A multisensory/crossmodal
perspective. Attention, Perception, & Psychophysics, 84(7), 2087–2114.
Di Stefano, N., & Spence, C. (2023). Perceptual similarity: Insights from crossmodal
correspondences. Review of Philosophy and Psychology, 1-30. https://doi.org/
10.1007/s13164-023-00692-y
Di Stefano, N., Vuust, P., & Brattico, E. (2022). Consonance and dissonance perception. A
critical review of the historical sources, multidisciplinary ndings, and main
hypotheses. Physics of Life Reviews, 43, 272–304. https://doi.org/10.1016/j.
plrev.2022.10.004
Dohn, A., Garza-Villarreal, E. A., Ribe, L. R., Wallentin, M., & Vuust, P. (2012). Musical
activity tunes up absolute pitch ability. Music Perception: An Interdisciplinary Journal,
31(4), 359–371.
Dohn, A., Garza-Villarreal, E. A., Chakravarty, M. M., Hansen, M., Lerch, J. P., &
Vuust, P. (2015). Gray-and white-matter anatomy of absolute pitch possessors.
Cerebral Cortex, 25(5), 1379–1388.
Elmer, S., H¨
anggi, J., Meyer, M., & J¨
ancke, L. (2013). Increased cortical surface area of
the left planum temporale in musicians facilitates the categorization of phonetic and
temporal speech sounds. Cortex, 49(10), 2812–2821.
Elmer, S., Rogenmoser, L., Kühnis, J., & J¨
ancke, L. (2015). Bridging the gap between
perceptual and cognitive perspectives on absolute pitch. Journal of Neuroscience, 35
(1), 366–371.
Evans, E. F. (1992). Auditory processing of complex sounds: An overview. Philosophical
Transactions of the Royal Society of London. Series B: Biological Sciences, 336(1278),
295–306. https://doi.org/10.1098/rstb.1992.0062
Fastl, H., & Hesse, A. (1984). Frequency discrimination for pure tones at short durations.
Acta Acustica united with Acustica, 56(1), 41–47.
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
15
Friedrich, A., Zentall, T., & Weisman, R. (2007). Absolute pitch: Frequency-range
discriminations in pigeons (Columba livia)–comparisons with zebra nches
(Taeniopygia guttata) and humans (Homo sapiens). Journal of Comparative Psychology,
121(1), 95–105.
Fujimoto, A., Enomoto, T., Takano, S., & Nose, T. (2004). Pitch perception abnormality
as a side effect of carbamazepine. Journal of Clinical Neuroscience, 11(1), 69–70.
Gaab, N., Schulze, K., Ozdemir, E., & Schlaug, G. (2006). Neural correlates of absolute
pitch differ between blind and sighted musicians. Neuroreport, 17(18), 1853–1857.
Gallace, A., Ngo, M. K., Sulaitis, J., & Spence, C. (2012). Multisensory presence in virtual
reality: Possibilities & limitations. In G. Ghinea, F. Andres, & S. Gulliver (Eds.),
Multiple sensorial media advances and applications: New developments in MulSeMedia
(pp. 1–38). Hershey, PA: IGI Global.
Gerbino, W. (2020). Amodal completion revisited. i-Perception, 11(4),
2041669520937323.
Glasser, S. (2021). Perceiving music through the lens of synaesthesia and absolute pitch.
Perception, 50(8), 690–708.
Gough, E. (1922). The effects of practice on judgments of absolute pitch. Archives of
Psychology, 7(47), i–93.
Gratton, I., Brandimonte, M. A., & Bruno, N. (2016). Absolute memory for tempo in
musicians and non-musicians. PloS One, 11(10), Article e0163558.
Gregersen, P. K., Kowalsky, E., Kohn, N., & Marvin, E. W. (1999). Absolute pitch:
Prevalence, ethnic variation, and estimation of the genetic component. The American
Journal of Human Genetics, 65(3), 911–913.
Gregersen, P. K., Kowalsky, E., Kohn, N., & Marvin, E. W. (2000). Early childhood music
education and predisposition to absolute pitch: Teasing apart genes and
environment. American Journal of Medical Genetics, 98(3), 280–282.
Gregersen, P. K., Kowalsky, E., Lee, A., Baron-Cohen, S., Fisher, S. E., Asher, J. E., …
Li, W. (2013). Absolute pitch exhibits phenotypic and genetic overlap with
synesthesia. Human Molecular Genetics, 22(10), 2097–2104.
Gregersen, P. K., & Kumar, S. (1996). The genetics of perfect pitch. American Journal of
Human Genetics, 59, A179.
Grifths, T. D., & Warren, J. D. (2002). The planum temporale as a computational hub.
Trends in Neurosciences, 25(7), 348–353.
Grossenbacher, P. G., & Lovelace, C. T. (2001). Mechanisms of synesthesia: Cognitive and
physiological constraints. Trends in Cognitive Sciences, 5(1), 36–41.
Haack, P. A., & Radocy, R. E. (1981). A case study of a chromesthetic. Journal of Research
in Music Education, 29(2), 85–90.
Halpern, A. R. (1989). Memory for the absolute pitch of familiar songs. Memory &
Cognition, 17(5), 572–581.
Hamilton, R. H., Pascual-Leone, A., & Schlaug, G. (2004). Absolute pitch in blind
musicians. Neuroreport, 15(5), 803–806.
H¨
anggi, J., Beeli, G., Oechslin, M. S., & J¨
ancke, L. (2008). The multiple synaesthete
ES—Neuroanatomical basis of interval-taste and tone-colour synaesthesia.
Neuroimage, 43(2), 192–203.
Heaton, P. (2003). Pitch memory, labelling and disembedding in autism. Journal of child
psychology and psychiatry, 44(4), 543–551.
Heaton, P., Hermelin, B., & Pring, L. (1998). Autism and pitch processing: A precursor for
savant musical ability? Music Perception, 15(3), 291–305.
Heaton, P., Davis, R. E., & Happ´
e, F. G. (2008). Research note: exceptional absolute pitch
perception for spoken words in an able adult with autism. Neuropsychologia, 46(7),
2095–2098.
Herceg, A., & Szab´
o, P. (2023). Absolute pitch: A literature review of underlying factors,
with special regard to music pedagogy. Psychomusicology: Music, Mind, and Brain.
https://doi.org/10.1037/pmu0000298
Hirose, H., Kubota, M., Kimura, I., Ohsawa, M., Yumoto, M., & Sakakihara, Y. (2002).
People with absolute pitch process tones with producing P300. Neuroscience Letters,
330(3), 247–250.
Hoeschele, M. (2017). Animal pitch perception: Melodies and harmonies. Comparative
Cognition & Behavior Reviews, 12, 5.
Hou, J., Chen, A. C., Song, B., Sun, C., & Beauchaine, T. P. (2017). Neural correlates of
absolute pitch: A review. Musicae Scientiae, 21(3), 287–302.
Hulse, S. H., Cynx, J., & Humpal, J. (1984). Absolute and relative pitch discrimination in
serial pitch perception by birds. Journal of Experimental Psychology: General, 113(1),
38–54. https://doi.org/10.1037/0096-3445.113.1.38
Hutmacher, F. (2019). Why is there so much more research on vision than on any other
sensory modality? Frontiers in Psychology, 10, 2246. https://doi.org/10.3389/
fpsyg.2019.02246
Itoh, K., Sakata, H., Kwee, I. L., & Nakada, T. (2017). Musical pitch classes have rainbow
hues in pitch class-color synesthesia. Scientic Reports, 7(1), 17781.
Itoh, K., Suwazono, S., Arao, H., Miyazaki, K. I., & Nakada, T. (2005).
Electrophysiological correlates of absolute pitch and relative pitch. Cerebral Cortex,
15(6), 760–769.
Jacobs, G. H. (2009). Evolution of colour vision in mammals. Philosophical Transactions of
the Royal Society, B: Biological Sciences, 364(1531), 2957–2967.
J¨
ancke, L., Langer, N., & H¨
anggi, J. (2012). Diminished whole-brain but enhanced peri-
sylvian connectivity in absolute pitch musicians. Journal of Cognitive Neuroscience, 24
(6), 1447–1461.
Julesz, B., & Hirsh, I. J. (1972). Visual and auditory perception - an essay of comparison.
In E. E. David, Jr., & P. B. Denes (Eds.), Human communication: A unied view (pp.
283–340). New York, NY: McGraw-Hill.
Katsuki, M., Higo, Y., Nishizawa, S., Yoshida, M., Kasahara, U., Sakamaki, K., … Koh, A.
(2022). Musician developed left putaminal hemorrhage and lost absolute pitch
ability—Case report. Acta Neurochirurgica, 164(8), 2229–2233.
Keenan, J. P., Thangaraj, V., Halpern, A. R., & Schlaug, G. (2001). Absolute pitch and
planum temporale. Neuroimage, 14(6), 1402–1408.
Kim, S. G., & Kn¨
osche, T. R. (2017). On the perceptual subprocess of absolute pitch.
Frontiers in Neuroscience, 11, 557.
Klein, M., Coles, M. G., & Donchin, E. (1984). People with absolute pitch process tones
without producing a P300. Science, 223(4642), 1306–1309.
Kolb, H. (2003). How the retina works: Much of the construction of an image takes place
in the retina itself through the use of specialized neural circuits. American Scientist,
91(1), 28–35.
Konno, S., Yamazaki, E., Kudoh, M., Abe, T., & Tohgi, H. (2003). Half pitch lower sound
perception caused by carbamazepine. Internal Medicine, 42(9), 880–883.
Kries, J. V. (1892). Über das absolute Geh¨
or. Zeitschrift für Psychologie, 3, 257–279.
Kubovy, M., & Schutz, M. (2010). Audio-visual objects. Review of Philosophy and
Psychology, 1, 41–61.
Kubovy, M., & Van Valkenburg, D. (2001). Auditory and visual objects. Cognition, 80,
97–126.
Kupferstein, H., & Walsh, B. J. (2016). Non-verbal paradigm for assessing individuals for
absolute pitch. World Futures, 72(7–8), 390–405.
Lawless, H. T., & Heymann, H. (1999). Sensory evaluation of food: Principles and practices.
New York: Springer Science & Business Media.
Lebeau, C., Tremblay, M. N., & Richer, F. (2020). Adaptation to a new tuning standard in
a musician with tone-color synesthesia and absolute pitch. Auditory Perception &
Cognition, 3(3), 113–123.
Lenhoff, H. M., Perales, O., & Hickok, G. (2001). Absolute pitch in Williams syndrome.
Music Perception, 18(4), 491–503.
Levitin, D. J. (1994). Absolute memory for musical pitch: Evidence from the production
of learned melodies. Perception & Psychophysics, 56, 414–423.
Levitin, D. J. (2004). L’oreille absolue [The absolute ear]. L’Anne´
e Psychologique, 104,
103–120.
Levitin, D. J., & Rogers, S. E. (2005). Absolute pitch: Perception, coding, and
controversies. Trends in Cognitive Sciences, 9(1), 26–33.
Lewis, D. (1939). Pitch as a psychological phenomenon. In Proceedings of the Music
Teachers National Association (pp. 121–133).
Lockhead, G. R., & Byrd, R. (1981). Practically perfect pitch. The Journal of the Acoustical
Society of America, 70(2), 387–389.
Loui, P. (2017). Absolute pitch. In The Oxford handbook of music psychology (2nd ed., pp.
81–94). Oxford University Press.
Loui, P., Li, H. C., Hohmann, A., & Schlaug, G. (2011). Enhanced cortical connectivity in
absolute pitch musicians: A model for local hyperconnectivity. Journal of Cognitive
Neuroscience, 23(4), 1015–1026.
Loui, P., Zamm, A., & Schlaug, G. (2012). Enhanced functional networks in absolute
pitch. Neuroimage, 63(2), 632–640.
Loui, P., Zamm, A., & Schlaug, G. (2013). Absolute pitch and synesthesia: Two sides of
the same coin? Shared and distinct neural substrates of music listening. (pp.
618–623). ICMPC.
Luria, A. R. (1968). The mind of the mnemonist. Basic Books.
MacDougal, R. (1898). Music imagery. A confession of experience. Psychological Review,
5(5), 463–476.
Martínez-Castilla, P., Sotillo, M., & Campos, R. (2013). Do individuals with Williams
syndrome possess absolute pitch? Child Neuropsychology, 19(1), 78–96.
Marvin, E. W., & Brinkman, A. R. (2000). The effect of key colour and timbre on absolute
pitch recognition in musical contexts. Music Perception, 18(2), 111–137.
Masataka, N. (2017). Neurodiversity, giftedness, and aesthetic perceptual judgment of
music in children with autism. Frontiers in Psychology, 8, 275513.
Matthen, M. (1988). Biological functions and perceptual content. The Journal of
Philosophy, 85(1), 5–27.
Mehr, S. A., Krasnow, M. M., Bryant, G. A., & Hagen, E. H. (2021). Origins of music in
credible signaling. Behavioral and Brain Sciences, 44, Article e60.
Meilleur, A. A. S., Jelenic, P., & Mottron, L. (2015). Prevalence of clinically and
empirically dened talents and strengths in autism. Journal of Autism and
Developmental Disorders, 45, 1354–1367.
Meyer, M. (1899). Is the memory of absolute pitch capable of development by training?
Psychological Review, 6(5), 514–516.
Miller, L. (1989). Musical savants: Exceptional skills in the mentally retarded. Hillsdale, NJ:
Erlbaum.
Miyazaki, K. I. (1988). Musical pitch identication by absolute pitch possessors.
Perception & Psychophysics, 44, 501–512.
Miyazaki, K. I. (1989). Absolute pitch identication: Effects of timbre and pitch region.
Music Perception, 7(1), 1–14.
Miyazaki, K. I. (1990). The speed of musical pitch identication by absolute-pitch
possessors. Music Perception, 8(2), 177–188.
Miyazaki, K. I. (2004a). How well do we understand absolute pitch? Acoustical Science
and Technology, 25(6), 426–432.
Miyazaki, K. I. (2004b). Recognition of transposed melodies by absolute-pitch possessors.
Japanese Psychological Research, 46(4), 270–282.
Miyazaki, K. I., Makomaska, S., & Rakowski, A. (2012). Prevalence of absolute pitch: A
comparison between Japanese and Polish music students. The Journal of the
Acoustical Society of America, 132(5), 3484–3493.
Miyazaki, K. I., Rakowski, A., Makomaska, S., Jiang, C., Tsuzaki, M., Oxenham, A. J., …
Lipscomb, S. D. (2018). Absolute pitch and relative pitch in music students in the
East and the West: Implications for aural-skills education. Music Perception: An
Interdisciplinary Journal, 36(2), 135–155.
Moher, D., Liberati, A., Tetzlaff, J., & Altman, D. G. (2009). Group P (2009) preferred
reporting items for systematic reviews and meta-analyses: The PRISMA statement.
BMJ, 339, Article b2535.
Mottron, L., Peretz, I., Belleville, S., & Rouleau, N. (1999). Absolute pitch in autism: A
case study. Neurocase, 5(6), 485–501.
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
16
Mottron, L., Dawson, M., & Souli`
eres, I. (2009). Enhanced perception in savant
syndrome: Patterns, structure and creativity. Philosophical Transactions of the Royal
Society, B: Biological Sciences, 364(1522), 1385–1391.
Neu, D. M. (1947). A critical review of the literature on “absolute pitch”. Psychological
Bulletin, 44(3), 249–266.
Niccolai, V., Jennes, J., Stoerig, P., & Van Leeuwen, T. M. (2012). Modality and
variability of synesthetic experience. The American Journal of Psychology, 125(1),
81–94.
O’Connell, T. S. (1974). The musical life of an autistic boy. Journal of Autism and
Childhood Schizophrenia, 4(3), 223–229.
Oechslin, M. S., Imfeld, A., Loenneker, T., Meyer, M., & J¨
ancke, L. (2010). The plasticity
of the superior longitudinal fasciculus as a function of musical expertise: A diffusion
tensor imaging study. Frontiers in Human Neuroscience, 3, 1076.
Oechslin, M. S., Meyer, M., & J¨
ancke, L. (2010). Absolute pitch—Functional evidence of
speech-relevant auditory acuity. Cerebral Cortex, 20(2), 447–455.
Ohnishi, T., Matsuda, H., Asada, T., Aruga, M., Hirakata, M., Nishikawa, M., …
Imabayashi, E. (2001). Functional anatomy of musical perception in musicians.
Cerebral Cortex, 11(8), 754–760.
Oka, A., & Kurihara, K. (2022). Otonona: A prototype for experiencing absolute pitch
using multimodal augmented reality. In 2022 IEEE 11th global conference on consumer
electronics (GCCE) (pp. 453–456). IEEE.
Parncutt, R., & Levitin, D. J. (2001). Absolute pitch. In The new grove dictionary of music
and musicians (pp. 37–38). Oxford, UK: Oxford University Press.
Peacock, K. (1985). Synesthetic perception: Alexander Scriabin’s color hearing. Music
Perception, 2(4), 483–505.
Peek, F., & Hanson, L. (2007). The life and message of the real rain man: The journey of a
mega-savant. National Professional Resources Inc./Dude Publishing.
Petrides, M. (2000). The role of the mid-dorsolateral prefrontal cortex in working
memory. Experimental Brain Research, 133, 44–54.
Petrides, M., & Pandya, D. N. (1988). Association ber pathways to the frontal cortex
from the superior temporal region in the rhesus monkey. Journal of Comparative
Neurology, 273(1), 52–66.
Petrovic, M., Antovic, M., Milankovic, V., & Acic, G. (2012). Interplay of tone and color:
Absolute pitch and synesthesia. In Proceedings in the 12
th
international conference on
music perception and cognition and the 8
th
triennial conference of the European Society for
the Cognitive Sciences of music (pp. 799–806). Greece: Thessaloniki. July 23-28th.
Pitchford, N. J., & Mullen, K. T. (2006). The developmental acquisition of basic colour
terms. Progress in Colour Studies, 2(8), 139–150.
Platel, H., Baron, J. C., Desgranges, B., Bernard, F., & Eustache, F. (2003). Semantic and
episodic memory of music are subserved by distinct neural networks. Neuroimage, 20
(1), 244–256.
Pring, L., Woolf, K., & Tadic, V. (2008). Melody and pitch processing in ve musical
savants with congenital blindness. Perception, 37(2), 290–307.
Prota, J., & Bidder, T. G. (1998). Perfect pitch. American Journal of Medical Genetics, 29
(4), 763–771.
Prota, J., Bidder, T. G., Optiz, J. M., & Reynolds, J. F. (1988). Perfect pitch. American
Journal of Medical Genetics, 29(4), 763–771.
The development of language: A critical period in humans. In Purves, D.,
Augustine, G. J., Fitzpatrick, D., et al. (Eds.), Neuroscience (3rd ed.,, (pp. 559–562).
(2001) pp. 559–562). Sunderland, MA: Sinauer Associates.
Qi, X. L., Meyer, T., Stanford, T. R., & Constantinidis, C. (2011). Changes in prefrontal
neuronal activity after learning to perform a spatial working memory task. Cerebral
cortex, 21(12), 2722–2732.
Rakowski, A., & Rogowski, P. (2007). Experiments on long-term and short-term memory
for pitch in musicians. Archives of Acoustics, 32(4), 815–826.
Ramachandran, V. S., & Hubbard, E. M. (2001). Synaesthesia–a window into perception,
thought and language. Journal of Consciousness Studies, 8(12), 3–34.
Revesz, G. (1953). Introduction to the psychology of music. London, UK: Longmans Green.
Reymore, L., & Hansen, N. C. (2020). A theory of instrument-specic absolute pitch.
Frontiers in Psychology, 11, Article 560877.
Rogenmoser, L., Arnicane, A., J¨
ancke, L., & Elmer, S. (2021). The left dorsal stream
causally mediates the tone labeling in absolute pitch. Annals of the New York
Academy of Sciences, 1500(1), 122–133.
Rogers, G. L. (1987). Four cases of pitch-specic chromesthesia in trained musicians with
absolute pitch. Psychology of Music, 15(2), 198–207.
Romani, M., Martucci, M., Visaggi, M. C., Prono, F., Valente, D., & Sogos, C. (2021).
What if sharing music as a language is the key to meeting halfway? Absolute pitch,
pitch discrimination and autism Spectrum disorder. La Clinica Terapeutica, 172(6),
577–590.
Ross, D. A., Gore, J. C., & Marks, L. E. (2005). Absolute pitch: Music and beyond. Epilepsy
& Behavior, 7(4), 578–601.
Rothen, N., Meier, B., & Ward, J. (2012). Enhanced memory ability: Insights from
synaesthesia. Neuroscience & Biobehavioral Reviews, 36(8), 1952–1963.
Ruhnau, P., Wetzel, N., Widmann, A., & Schr¨
oger, E. (2010). The modulation of auditory
novelty processing by working memory load in school age children and adults: A
combined behavioral and event-related potential study. BMC Neuroscience, 11(1),
1–14.
Saffran, J. R. (2003). Statistical language learning: Mechanisms and constraints. Current
Directions in Psychological Science, 12(4), 110–114.
Saffran, J. R., & Griepentrog, G. J. (2001). Absolute pitch in infant auditory learning:
Evidence for developmental reorganization. Developmental Psychology, 37(1), 74.
Savage, P. E., Loui, P., Tarr, B., Schachner, A., Glowacki, L., Mithen, S., & Fitch, W. T.
(2021). Music as a coevolved system for social bonding. Behavioral and Brain
Sciences, 44, Article e59.
Schellenberg, E. G., & Trehub, S. E. (2003). Good pitch memory is widespread.
Psychological Science, 14(3), 262–266.
Schellenberg, E. G., & Trehub, S. E. (2008). Is there an Asian advantage for pitch
memory? Music Perception, 25(3), 241–252.
Schlaug, G., J¨
ancke, L., Huang, Y., & Steinmetz, H. (1995). In vivo evidence of structural
brain asymmetry in musicians. Science, 267(5198), 699–701.
Schmithorst, V. J. (2005). Separate cortical networks involved in music perception:
Preliminary functional MRI evidence for modularity of music processing.
Neuroimage, 25(2), 444–451.
Schomaker, J., & Meeter, M. (2014). Novelty detection is enhanced when attention is
otherwise engaged: An event-related potential study. Experimental Brain Research,
232, 995–1011.
Schulze, K., Gaab, N., & Schlaug, G. (2009). Perceiving pitch absolutely: Comparing
absolute and relative pitch possessors in a pitch memory task. BMC Neuroscience, 10
(1), 1–13.
Seashore, C. E. (1940). The psychology of music. Acquired pitch vs. absolute pitch. Music
Educators Journal, 26(6), 18.
Sergeant, D. (1969). Experimental investigation of absolute pitch. Journal of Research in
Music Education, 17(1), 135–143.
Sharma, V. V., Thaut, M., Russo, F. A., & Alain, C. (2023). Absolute pitch:
Neurophysiological evidence for early brain activity in prefrontal cortex. Cerebral
Cortex, 33(10), 6465–6473.
Siegel, J. A. (1974). Sensory and verbal coding strategies in subjects with absolute pitch.
Journal of Experimental Psychology, 103(1), 37–44.
Simner, J., & Hubbard, E. M. (Eds.). (2013). The Oxford handbook of synesthesia. Oxford,
UK: Oxford University Press.
Simner, J., Mulvenna, C., Sagiv, N., Tsakanikos, E., Witherby, S. A., Fraser, C., …
Ward, J. (2006). Synaesthesia: The prevalence of atypical cross-modal experiences.
Perception, 35(8), 1024–1033.
Siuda-Krzywicka, K., Boros, M., Bartolomeo, P., & Witzel, C. (2019). The biological bases
of colour categorisation: From goldsh to the human brain. Cortex, 118, 82–106.
Snyder, A. W., & Mitchell, D. J. (1999). Is integer arithmetic fundamental to mental
processing?: The mind’s secret arithmetic. Proceedings of the Royal Society of London,
Series B: Biological Sciences, 266(1419), 587–592.
Spence, C. (2019). On the relative nature of (pitch-based) crossmodal correspondences.
Multisensory Research, 32(3), 235–265. https://doi.org/10.1163/22134808-
20191407
Spence, C., & Di Stefano, N. (2022). Coloured hearing, colour music, colour organs, and
the search for perceptually meaningful correspondences between colour and sound.
i-Perception, 13(3), 20416695221092802.
Spence, C., & Di Stefano, N. (2023). Sensory translation between audition and vision.
Psychonomic Bulletin & Review, 1-28. https://doi.org/10.3758/s13423-023-02343-w
Spence, C., & Di Stefano, N. (2024). What, if anything, can be considered an amodal
sensory dimension? Psychonomic Bulletin & Review, 1–19.
Stanutz, S., Wapnick, J., & Burack, J. A. (2014). Pitch discrimination and melodic
memory in children with autism spectrum disorders. Autism, 18(2), 137–147.
Stevens, S. S. (1957). On the psychophysical law. Psychological Review, 64(3), 153–181.
https://doi.org/10.1037/h0046162
Stevens, S. S. (1971). Issues in psychophysical measurement. Psychological Review, 78(5),
426–450.
Stumpf, C. (1882, 1890). Tonpsychologie. Leipzig: Hirzel.
Suriadi, M. M., Usui, K., Tottori, T., Terada, K., Fujitani, S., Umeoka, S., … Inoue, Y.
(2015). Preservation of absolute pitch after right amygdalohippocampectomy for a
pianist with TLE. Epilepsy & Behavior, 42, 14–17.
Szyfter, K., & Witt, M. P. (2020). How far musicality and perfect pitch are derived from
genetic factors? Journal of Applied Genetics, 61(3), 407–414.
Takeuchi, A. H., & Hulse, S. H. (1993). Absolute pitch. Psychological Bulletin, 113(2),
345–361.
Tan, Y. T., McPherson, G. E., Peretz, I., Berkovic, S. F., & Wilson, S. J. (2014). The genetic
basis of music ability. Frontiers in Psychology, 5, 658.
Terhardt, E., & Seewann, M. (1983). Aural key identication and its relationship to
absolute pitch. Music Perception, 1, 63–83.
Terhardt, E., & Ward, W. D. (1982). Recognition of musical key: Exploratory study.
Journal of the Acoustical Society of America, 72, 26–33.
Theusch, E., Basu, A., & Gitschier, J. (2009). Genome-wide study of families with
absolute pitch reveals linkage to 8q24. 21 and locus heterogeneity. The American
Journal of Human Genetics, 85(1), 112–119.
Treffert, D. A. (2009). The savant syndrome: An extraordinary condition. A synopsis:
Past, present, future. Philosophical Transactions of the Royal Society, B: Biological
Sciences, 364(1522), 1351–1357.
Treisman, A. (1982). Perceptual grouping and attention in visual search for features and
for objects. Journal of Experimental Psychology: Human Perception and Performance, 8
(2), 194–214.
Van Hedger, S. C., Heald, S. L., Koch, R., & Nusbaum, H. C. (2015). Auditory working
memory predicts individual differences in absolute pitch learning. Cognition, 140,
95–110.
Van Hedger, S. C., Heald, S. L., & Nusbaum, H. C. (2019). Absolute pitch can be learned
by some adults. PLoS One, 14(9), Article e0223047.
Vernon, P. E. (1977). Absolute pitch: A case study. British Journal of Psychology, 68(4),
485–489.
Von Helmholtz, H. L. (1878/1971). Treatise on physiological optics (Vol. II). New York:
Dover Publications.
Wan, C. Y., & Schlaug, G. (2010). Music making as a tool for promoting brain plasticity
across the life span. The Neuroscientist, 16(5), 566–577.
Wang, L., Pfordresher, P. Q., Jiang, C., & Liu, F. (2021). Individuals with autism spectrum
disorder are impaired in absolute but not relative pitch and duration matching in
speech and song imitation. Autism Research, 14(11), 2355–2372.
N. Di Stefano and C. Spence
Cognition 249 (2024) 105805
17
Ward, J., Field, A. P., & Chin, T. (2019). A meta-analysis of memory ability in
synaesthesia. Memory, 27(9), 1299–1312.
Ward, J., Huckstep, B., & Tsakanikos, E. (2006). Sound-colour synaesthesia: To what
extent does it use cross-modal mechanisms common to us all? Cortex, 42(2),
264–280.
Ward, W. D. (1999). Absolute pitch. In D. Deutsch (Ed.), The psychology of music (pp.
265–298). New York, NY: Academic Press.
Ward, W. D., & Burns, E. M. (1982). Absolute pitch. In D. Deutsch (Ed.), The psychology of
music (pp. 431–451). San Diego, CA: Academic Press.
Warren, J. D., Uppenkamp, S., Patterson, R. D., & Grifths, T. D. (2003). Separating pitch
chroma and pitch height in the human brain. Proceedings of the National Academy of
Sciences, 100(17), 10038–10042.
Warren, R. M. (2013). Auditory perception: A new synthesis. Elsevier.
Watt, H. J. (1917). The psychology of sound. Cambridge, UK: Cambridge University Press.
Wayman, J. W., Frisina, R. D., Walton, J. P., Hantz, E. C., & Crummer, G. C. (1992).
Effects of musical training and absolute pitch ability on event-related activity in
response to sine tones. The Journal of the Acoustical Society of America, 91(6),
3527–3531.
Weidensall, C. J. (1905). Studies in pitch discrimination. Psychological Bulletin, 2(6),
216–217. https://doi.org/10.1037/h0067750
Weisman, R. G., Williams, M. T., Cohen, J. S., Njegovan, M. G., & Sturdy, C. B. (2006).
The comparative psychology of absolute pitch. In E. A. Wasserman, & T. R. Zentall
(Eds.), Comparative cognition: Experimental explorations of animal intelligence (pp.
71–88). New York, NY: Oxford University Press.
Welch, G. F. (1988). Observations on the incidence of absolute pitch (AP) ability in the
early blind. Psychology of Music, 16(1), 77–80.
Wengenroth, M., Blatow, M., Heinecke, A., Reinhardt, J., Stippich, C., Hofmann, E., &
Schneider, P. (2014). Increased volume and function of right auditory cortex as a
marker for absolute pitch. Cerebral Cortex, 24(5), 1127–1137.
Whipple, G. M. (1903). Studies in pitch discrimination. The American Journal of
Psychology, 14(3/4), 289–309.
Wilson, C. W. (1911). The gift of absolute pitch. Musical Opinion, 34, 753–754.
Wilson, S. J., Lusher, D., Wan, C. Y., Dudgeon, P., & Reutens, D. C. (2009). The
neurocognitive components of pitch processing: Insights from absolute pitch.
Cerebral Cortex, 19(3), 724–732.
Wong, Y. K., Lui, K. F. H., Yip, K. H. M., & Wong, A. C.-N. (2020). Is it impossible to
acquire absolute pitch in adulthood? Attention, Perception, & Psychophysics, 82,
1407–1430. https://doi.org/10.3758/s13414-019-01869-3
Zakay, D., Roziner, I., & Ben-Arzi, S. (1984). On the nature of absolute pitch. Archiv für
Psychologie, 136(2), 163–166.
Zarate, J. M., & Zatorre, R. J. (2008). Experience-dependent neural substrates involved in
vocal pitch regulation during singing. Neuroimage, 40(4), 1871–1887.
Zatorre, R. J. (1989). Effects of temporal neocortical excisions on musical processing.
Contemporary Music Review, 4(1), 265–277.
Zatorre, R. J. (2003). Absolute pitch: A model for understanding the inuence of genes
and development on neural and cognitive function. Nature Neuroscience, 6(7),
692–695.
Zatorre, R. J., & Beckett, C. (1989). Multiple coding strategies in the retention of musical
tones by possessors of absolute pitch. Memory & Cognition, 17(5), 582–589.
Zatorre, R. J., Perry, D. W., Beckett, C. A., Westbury, C. F., & Evans, A. C. (1998).
Functional anatomy of musical processing in listeners with absolute pitch and
relative pitch. Proceedings of the National Academy of Sciences, 95(6), 3172–3177.
Zdzinski, S. F., Ireland, S. J., Wuttke, B. C., Belen, K. E., Olesen, B. C., Doyle, J. L., &
Russell, B. E. (2019). An exploratory neuropsychological case study of two
chromesthetic musicians. Research Perspectives in Music Education, 20(1), 65–82.
Zeki, S. (1993). A vision of the brain. London, UK: Blackwell Science.
N. Di Stefano and C. Spence
