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Abstract Prosopagnosia is the inability to recognize
someone by the face alone in the absence of sensory or
intellectual impairment. In contrast to the acquired
form of prosopagnosia we studied the congenital form.
Since we could recently show that this form is inherited
as a simple monogenic trait we called it hereditary
form. To determine whether not only face recognition
and neuronal processing but also the perceptual
acquisition of facial information is specific to proso-
pagnosia, we studied the gaze behaviour of four
hereditary prosopagnosics in comparison to matched
control subjects. This rarely studied form of proso-
pagnosia ensures that deficits are limited to face rec-
ognition. Whereas the control participants focused
their gaze on the central facial features, the hereditary
prosopagnosics showed a significantly different gaze
behaviour. They had a more dispersed gaze and also
fixated external facial features. Thus, the face recog-
nition impairment of the hereditary prosopagnosics is
reflected in their gaze behaviour.
Introduction
Human beings are extremely competent at recognizing
faces quickly and accurately (Bruce, 1988; Bruce &
Young, 1998; Carey, 1996). In the last 2 decades, re-
sults of electrophysiological and neuroimaging studies
suggest that the recognition of faces is a highly specific
process. This view is supported by the fact that a spe-
cific impairment such as prosopagnosia exists that
concerns the recognition of faces only. The most
important characteristic of prosopagnosia—a term that
is first introduced by Bodamer (1947)—is the difficulty
in recognizing famous or familiar faces without marked
impairment of the recognition of other visual stimuli
(Benton, 1990; de Gelder & Rouw, 2000; Jones &
Tranel, 2001; McConachie, 1976; Nunn, Postma, &
Pearson, 2001; Temple, 1992).
Almost all cases reported in the literature are of the
acquired form. The diagnosis in these cases is often
self-reported because of the sudden loss of a hitherto
unimpaired skill. The congenital or developmental
forms are apparent from early childhood and typically
no traumatic, toxic or other exogen affects are known.
Participants with this ‘‘lifelong’’ impairment are
thinking of having just low-functioning (face) recogni-
tion skills or even are not aware of the deficit at all.
This may be the reason that the congenital form might
have been mostly overlooked. A slowly growing
number of only a few congenital prosopagnosic cases
are reported (Ariel & Sadeh, 1996; Bentin, Deouell, &
Soroker, 1999; De Gelder & Rouw, 2000; Duchaine,
2000; Duchaine, Parker, & Nakayama, 2003; de Haan,
1999; de Haan & Campbell, 1991; Hasson, Avidan,
Deouell, Bentin, & Malach, 2003; Jones & Tranel,
2001; Kress & Daum, 2003; McConachie, 1976; Nunn
G. Schwarzer (&) Æ S. Huber Æ C. Groß Æ M. Hipfel
University of Giessen, Otto-Behaghel-Str. 10F,
35394 Giessen, Germany
e-mail: gudrun.schwarzer@psychol.uni-giessen.de
M. Gru
¨
ter Æ T. Gru
¨
ter Æ I. Kennerknecht
Institut fu
¨
r Humangenetik, Westfa
¨
lische
Wilhelms-Universita
¨
t, Mu
¨
nster, Germany
Psychological Research
DOI 10.1007/s00426-006-0068-0
123
ORIGINAL ARTICLE
Gaze behaviour in hereditary prosopagnosia
Gudrun Schwarzer Æ Susanne Huber Æ
Martina Gru
¨
ter Æ Thomas Gru
¨
ter Æ Cornelia Groß Æ
Melanie Hipfel Æ Ingo Kennerknecht
Received: 11 November 2004 / Accepted: 25 April 2006
Springer-Verlag 2006
et al., 2001; Temple, 1992, for a review see Behrmann
& Avidan 2005). The terms ‘‘congenital’’ and ‘‘devel-
opmental’’ are often used synonymously. Sensu strictu
they say nothing to the aetiology but only to the time of
onset, ‘‘at birth’’ and somewhere ‘‘during develop-
ment’’. These descriptions leave open whether it is
congenital by hereditary or acquired by birth (e.g. by
perinatal asphyxia) or during development (e.g. by
encephalitis). There is a lack of data for a putative
acquired congenital form and until recently only some
reports about a hereditary form exist. McConachie
(1976) and de Haan (1999) were the only one reporting
familial transmission from mother to daughter and fa-
ther to two daughters (and probably to one son),
respectively. Recently we could demonstrate that the
congenital form is hereditary (ab ovo) and very com-
mon (Gru
¨
ter, 2004; Gru
¨
ter, Gru
¨
ter, Bell, Horst, &
Laskowskiet al., in press; Kennerknecht, Gru
¨
ter, Gru
¨
-
ter, Otte, & Neumann et al., 2002). In all cases where
we could evaluate the family history we found further
first-degree impaired probands fitting to a simple
autosomal dominant segregation pattern. We therefore
coined the term ‘‘hereditary prosopagnosia’’. Heredi-
tary prosopagnosia is certainly a qualitatively distinct
deficit from the acquired form. Whether it supports the
traditional concept of an associative/mnestic disorder
remains an open question. In our personal experience
with 38 hereditary prosopagnosics (Gru
¨
ter et al., in
press and unpublished data) the perception of facial
details is not grossly distorted. All hereditary prosop-
agnosics can tell a normal perception of attractiveness,
emotions, and easy identification of gender. In this
way, hereditary prosopagnosia might be rather an
associative/mnestic deficit.
Up to now studies on congenital prosopagnosia tried
to find out, whether it is associated with an unusual
neuronal or electrophysiological pattern (Ariel &
Sadeh, 1996; Bentin et al., 1999; Choisser & de Haan,
1999; Duchaine, 2000; Hadjikhani & de Gelder, 2002;
McConachie, 1976; Nunn et al., 2001). For example,
there is evidence that congenital prosopagno-
sics—although not suffering from a neurological
disease—do not show the normal pattern of brain
activity such as higher fMRI activity to faces than to
objects in the fusiform face area and inferior occipital
gyrus (Barton, Press, Keenan, & O’Connor, 2002;
Hadjikhani & de Gelder, 2002). However, a recent
study carried out by Hasson et al. (2003) showed that
the face-related activation pattern of a congenital
prosopagnosic subject in the ventral occipito-temporal
cortex was similar to that observed in control subjects.
Thus, the neuronal correlates of congenital prosopag-
nosia are still under investigation.
Little is known about the perceptual processes that
accompany congenital prosopagnosia. It is still un-
known whether it is not only specific with regard to
face recognition performance and neuronal processing
but possibly also with regard to processes of visual
perception such as the acquisition of facial information
in particular. As visual information acquisition is ex-
pressed by gaze behaviour (Viviani, 1990), in the
present study we examined the gaze pattern in hered-
itary prosopagnosics as opposed to control participants
when they were encoding and recognizing faces.
Concerning the acquired form of prosopagnosia
there are a few studies that have analysed the gaze
behaviour during face recognition (e.g., Le, Raufaste,
& Demonet,
2003; Rizzo, Hurtig, & Damasio, 1987).
These studies showed no significant differences on gaze
behaviour during face recognition between the pros-
opagnosics and control participants. However, this re-
sult is not very surprising because these prosopagnosic
probands had normal face recognition abilities before
they acquired prosopagnosia. Therefore, it is possible
that they retained their internal schema of visually
examining a face even after they acquired prosopag-
nosia.
In contrast to the acquired type, with a large variety
of brain damages and hence accompanying deficits, the
investigation of hereditary prosopagnosics allowed us
to study a homogeneous group of prosopagnosics, who
all have difficulties in recognizing faces from the very
beginning of life without any other neurologic or per-
ceptional impairments.
Method
Face recognition performance and gaze behaviour
were studied in two tasks, in the ‘‘famous face task’’
and in the ‘‘unfamiliar face task’’ which are described
below. Both tasks were constructed in such a way that
even the hereditary prosopagnostic participants were
able to recognize some of the faces. This in turns
should make it possible for us to analyse the gaze
behaviour of both groups in terms of faces that had
been recognized and those face that had not been
recognized.
Participants
This study was part of a broader study carried out with
ethical committee approval from the University of
Mu
¨
nster, protocol No 3XKenn2, ‘‘Genotype/phenotype
correlation of prosopagnosia (syn. face blindness)’’.
Psychological Research
123
Probands were recruited after informed consent. In a
pilot study we described recruitment and diagnostic
assessment of 38 prosopagnosic participants in detail
(Gru
¨
ter, 2004, Gru
¨
ter et al., in press). In short, impaired
participants were identified among personal acquain-
tances and further by providing an Internet portal. The
diagnostic approach of the hereditary prosopagnosics
consisted of (1) anamnestic data excluding any event of
brain lesion (perinatal asphyxia, epileptic attack, men-
ingitis, injuries, brain surgery) or neurological or psy-
chiatric disorders, and of (2) a semistructural interview
concentrating on cognitive features and including de-
tailed data about the individual family history.
All hereditary prosopagnosics reported that
throughout their entire life they had been unable to
recognize people by their faces alone. They reported
that context enables them to recognize others more
easily and that they identify people by their hair, voice
etc. Furthermore, they reported that they sometimes
do not even recognize very close relatives and that they
avoid participating in large events where they cannot
be sure who they will meet.
In order to assess the diagnoses more objectively 8
out of 38 hereditary prosopagnosics from 7 families
agreed with in-depth testing (Warrington Recognition
Memory Test for Faces, RMF, Warrington 1984, fa-
mous and family faces tests, learning tests for internal
and external facial features, and a measure of mental
imagery for face and non-face images, see Gru
¨
ter et al.,
in press). These findings were fully compatible with the
data of the individual interviews as was true with the
respective familial segregation data. Thus, since the
eight hereditary prosopagnosics with in-depth testing
were randomly chosen it is likely that the other
hereditary prosopagnosics show a similar pattern of
face recognition abilities.
The probands of the present study stemmed from
the pool of hereditary prosopagnisics described above.
They consisted of three persons of one large family LI,
HE (females, 71 years), and TH (male, 45 years) de-
scribed in Gru
¨
ter et al. (in press) and a further person
GM (female, 35 years) from this pool. All probands
had a positive family history of prosopagnosia with
several impaired first-degree relatives, respectively.
Moreover, none of them had a history of neurological
or other disorders. Their visual acuity was normal or
corrected to normal. Intellectual abilities were normal
or above average.
4 control subjects (control group 1) who were mat-
ched in gender and approximate age to the hereditary
prosopagnosics (3 women, 35, 72, 73 years of age; 1
man, 42 years of age) participated in the ‘‘famous face
task’’. In the ‘‘unfamiliar face task’’, another sample of
4 control subjects (control group 2: 2 women, 60,
41 years of age; 2 men, 32, 78 years of age) was studied.
Since we ran the control study of the ‘‘unfamiliar face
task’’ first and the participants were from the USA, we
assembled a further control group coming from Ger-
many for the ‘‘famous face task’’ because this task
consisted of German famous people.
Stimuli
The stimuli of the ‘‘famous face task’’ consisted of 25
faces of well-known German politicians, TV stars and
highly popular singers and scientists (see Appendix). In
a pilot study, ten students were asked to name the faces
and to indicate their professions. The results showed
92% correct answers. The stimuli of the ‘‘unfamiliar
face task’’ were chosen from the face database PICS
(Psychological Image Collection at Stirling, 2002).
They consisted of 20 target faces and 20 distractor fa-
ces. The stimuli of both tasks were presented at a visual
angle of 12.5·9.8 on a light grey background.
Apparatus
The SMI remote eye-tracker (refresh rate 50 Hz) was
used to track eye movements (spatial accuracy of gaze
direction 0.5–1). This operates by illuminating the eye
with infra-red light and monitoring its reflection off
components of the eye via a video camera. The stimuli
of both tasks were displayed via a PC (single Pentium
II processor, 512 MB RAM) on a monitor (21 in. with
a resolution of 1,024 · 768 pixels) that was mounted
together with the eye-tracking camera and the infra-
red light source inside a so-called gaze-catch box. Gaze
behaviour was recorded on a second computer, which
was connected to the eye-tracking computer. The two
computers communicated via serial connection to
provide synchronization of stimulus on/off-set and start
and stop of recording of the gaze behaviour. The gaze-
catch box had a 16 · 2 cm slit where the participants
could look inside. A chin-rest was mounted below the
slit so that the head movements of the participants
were reduced to a minimum.
Procedure
Participants were tested individually. Prior to the
experiment, participants were told that their gaze
behaviour would be recorded, and the eye-tracker was
calibrated once by a nine-point calibration technique.
Before the presentation of each face, a small white
fixation-cross appeared at the centre of the monitor.
The ‘‘famous face task’’ consisted of two blocks. In the
Psychological Research
123
first block (recognition), participants were asked to
indicate whether they knew any of the 25 faces. The
faces were presented for 7 s each. The participants
indicated that they know the face by lifting up their
right arm. This method was chosen in order to ensure
gaze recording was not affected by possible head
movements accompanying speech. Once the partici-
pant gave the answer, the experimenter pressed a
keyboard button to stop eye-movement recording. It
was made sure that the experimenter stopped the eye-
movement recording reliably. Upon pressing the but-
ton, the face disappeared and the fixation cross reap-
peared on the screen until the next trial was started by
the experimenter. Thus, gaze behaviour was recorded
from stimulus onset until the experimenter pressed a
button following the response of the participant. This
time interval also indicates the corresponding reaction
time. In a second block (naming), the same faces were
presented again and participants were asked to name
the faces and to indicate the profession of the person.
No reaction times and eye movements were measured.
In the ‘‘unfamiliar face task’’ the participants per-
formed a forced-choice recognition task on the unfa-
miliar faces. In the encoding phase, subjects were
shown a single target face for 7 s. After a short delay of
1.5 s—in the subsequent recognition phase—the target
face was presented as before but now paired with a
distractor face, e.g. each target face was shown side by
side with a distractor face. The sides (right, left) of the
target faces were balanced. The participants’ task was
to indicate whether the target face was on the right or
left side by lifting up the right or left arm. Eye move-
ments were recorded.
Results
To test the face recognition impairment of the hered-
itary prosopagnosics, their performance in the ‘‘famous
face task’’ was compared to that of the four participants
of control group 1. The recognition performance was
measured as the percentage of correct recognition, as
the percentage of correct naming and as the percentage
of a so-called combined score. In the combined-score
only those answers were counted as correct indicating
that the participant correctly recognized the face and
was able to correctly name the face or the profession of
the person. Concerning each of the three measures, the
hereditary prosopagnosics’ performance was lower
than that of the controls (recognition: F(1, 6) = 4.54,
P = .07, naming: F(1, 6) = 4.41, P = .08, combined-
score: F(1, 6) = 5.34. P = .06). The combined score of
the hereditary prosopagnosics was 60% correct and the
score of the control participants was 87% correct. Thus,
in face recognition and naming hereditary prosopag-
nosics’ performance was nearly significant lower than
that of the controls. The small number of participants
should be considered by interpreting this difference
that only slightly failed the level of significance. How-
ever, when comparing the hereditary prosopagnosics’
measure for correctly naming the faces to the scores of
the pilot group used for evaluating the famous faces
(naming the famous faces), the difference was highly
significant, F(1, 11) = 20.04, P < .001.
The reaction times of the four hereditary prosop-
agnosics (‘‘famous face task’’) were compared to those
of the four participants of control group 1. Here the
hereditary prosopagnosics’ reaction times were signif-
icantly longer than those of the controls, (F(1,
6) = 31.7, P < .01, PA: M = 2.50 s, SD = 0.385 s, non-
PA: M = 1.361 s, SD = 0.128).
In the ‘‘unfamiliar face task’’ the hereditary pros-
opagnosics and the four subjects of control group 2
showed nearly perfect recognition performance. In
each group only one subject failed to recognize one of
the 20 faces.
In the ‘‘famous face task’’ and in the ‘‘unfamiliar
face task’’ fixations were calculated with a dispersion
algorithm with a minimum fixation duration of 100 ms
and a dispersion area of 0.5 (Stark & Ellis, 1981). In
the ‘‘famous face task’’ fixations were computed from
the onset until the end of face presentation in the
‘‘recognition’’ condition (7 s), and in the ‘‘unfamiliar
face task’’ fixations were calculated during the encod-
ing phase when participants looked at the target faces
for 7 s. For each target face an ellipse-shaped area that
closely matched the fixations was calculated by prin-
cipal component analysis i.e., the area of the ellipse
that included 85.35% of the fixations was measured
(Oliveira, Simpson & Nadal, 1996). For each partici-
pant the average ellipse areas were computed in rela-
tion to the average size of all faces presented (relative
fixation area).
In both tasks the results were evident (see Fig. 1 left
panel, Fig. 2): In the ‘‘famous face task’’ and in the
‘‘unfamiliar face task’’ the relative fixation area used
by the hereditary prosopagnosics was significantly
greater than that of the participants of the corre-
sponding control groups (group 1 in the ‘‘famous face
task’’ and group 2 in the ‘‘unfamiliar face task’’) (Task
1: F(1, 6) = 15.80, P < .01; Task 2: F(1, 6) = 13.31,
P < .01). To rule out the possibility that hereditary
prosopagnosics in the ‘‘famous face task’’ used a
greater area of fixations than the controls because they
were significantly less able to recognize the famous
faces correctly, the relative fixation areas were com-
Psychological Research
123
pared between hereditary prosopagnosics and control
participants (group 1) for faces correctly recognized
and faces not recognized separately. As depicted in
Fig. 1 (middle and right panel), hereditary prosopag-
nosics used a significantly greater relative fixation area
than the control participants (faces recognized cor-
rectly: F(1, 6) = 8.89, P < .05; faces not recognized:
F(1, 6) = 7.23, P < .05), no matter whether faces were
recognized or not. In both tasks the average number of
fixations per second (Task 1: F(1, 8) = 0.53, P > .05;
Task 2: F(1, 8) = 1.13, P > .05) and the average fixation
length did not differ between hereditary prosopagno-
sics and controls (Task 1: F(1, 8) = 2.56, P > .05; Task
2: F(1, 8) = 2.13, P > .05).
The fixation areas of a hereditary prosopagnosic and
a control proband depicted in Figs. 3 and 4 illustrate
the differences in fixation patterns typical for each
group of participants. As can be seen, when recogniz-
ing a famous face or when encoding an unfamiliar face,
the controls focused their gaze predominately on the
central section of the face (eyes, nose, mouth) whereas
the hereditary prosopagnosics showed a more dis-
persed gaze in both tasks. They fixated not only the
central facial features but mostly also external features
such as the hair, neck, or chin.
Discussion
The results of the present study show that when faces
are viewed hereditary prosopagnosics use a signifi-
cantly different fixation pattern than control partici-
pants. Whereas the controls focused their gaze on the
central facial features, the hereditary prosopagnosics
had a more dispersed gaze and also fixated external
facial features.
With regard to face recognition performance our
results are in line with previous findings. The typical
difficulties hereditary prosopagnosics have when rec-
ognizing famous faces and their prolonged reaction
times were confirmed (Bentin et al., 1999; Duchaine,
2000; Nunn et al., 2001). Also, in agreement with pre-
vious findings hereditary prosopagnosics showed no
difficulty in recognizing unfamiliar faces when the
target faces to be recognized were presented exactly as
in the encoding phase (Ariel & Sadeh, 1996; Duchaine,
2000; Nunn et al., 2001). Thus, when faces have to be
matched within a short period of time and no access to
long-term memory is necessary, hereditary prosopag-
Fig. 1 Relative fixation area in hereditary prosopagnosics (PA)
and control subjects (control group 1) when recognising famous
faces. Relative fixation area is defined as the average ellipse that
covered 83.35% of the fixations (Stark & Ellis, 1981) in relation
to the average size of all faces presented. Error bars indicate
standard deviation. Left panel shows the relative fixation area in
all trials in which hereditary prosopagnosics (PA) and control
subjects responded to the faces. Middle panel shows the relative
fixation area in the trials in which hereditary prosopagnosics and
control subjects recognized the faces correctly. For each
participant, fixation behavior was analysed from stimulus onset
until participant’s response. Right panel shows relative fixation
area for the trials in which hereditary prosopagnosics and control
subjects did not recognize the faces. For each participant,
fixation behavior was analysed from stimulus onset until the
end of stimulus presentation (7 s)
Fig. 2 Relative fixation area in hereditary prosopagnosics (PA)
and control subjects (control group 2) when encoding unfamiliar
faces. Error bars indicate standard deviation. Fixation area was
analysed when unfamiliar faces were presented for 7 seconds
each and participants’ task was to look at the faces that had to be
identified in the subsequent recognition phase
Psychological Research
123
nosics show the same performance as control pro-
bands.
More importantly, our results show that the gaze of
hereditary prosopagnosics is more dispersed when
looking at faces as opposed to that of controls who
focus on the central features of the face. This holds
true for the encoding and recognition of famous faces
and the encoding of unfamiliar faces. Furthermore, in
both cases the dispersed gaze pattern of the heredi-
tary prosopagnosics and the focused gaze of the
control subjects were independent of their recognition
performance. Even if the hereditary prosopagnosics
recognized a face correctly, compared to the control
participants their gaze was significantly more dis-
persed. Thus, the decisive factor for the differences in
gaze behaviour is whether the participants belong to
the group of hereditary prosopagnosics or not.
This relationship between gaze behaviour and being
a hereditary prosopagnosic or not can be seen in
analogy to the relationship between fixation behaviour
and different states of expertise (Viviani, 1990). For
example, some technical images (Chest X-rays, sono-
grams etc.) contain details which are only meaningful
to experts. Skilled professionals immediately concen-
trate fixations on these details, whereas laymen tend to
search for other informative regions (Carmody, No-
dine, & Kundel, 1980; Kundel & Nodine, 1983). Ana-
logically, the control probands, as so-called face
experts, cluster their fixations around the central facial
features, i.e, around those places with high informative
value (Antes, 1974; Henderson, Falk, Minut, Dyer, &
Mahadevan, 2001; Janik, Wellens, Goldberg, & Del-
l’Osso, 1978; Viviani, 1990; Walker-Smith, Gale, &
Findlay, 1977). In general, places with high informative
value are associated with those parts of the stimulus
which help the viewer to understand the meaning of
the stimulus (Yarbus, 1967). Hereditary prosopagno-
sics, in contrast, also search visually for places with
high informative values; however these are not the
central facial features but other external features that
could also be informative for recognition.
Since gaze behaviour can be understood as a crite-
rium that differentiates between hereditary and control
participants, the question arises of whether gaze
behaviour of hereditary prosopagnosics differs from
other untypical gaze patterns as well. For example,
clinical studies of face processing show that gaze
behaviour differs between control participants and
patients with disorders such as schizophrenia and aut-
ism (Manor, Gordon, Williams, Rennie, & Bahrama-
liet al., 1999; Pelphrey, Sasson, Reznick, Paul, &
Goldman, et al., 2002). The studies showed that pa-
tients with autism and schizophrenia look unsystem-
atically at only one or two non-central facial features
such as the ears or chin and avoid looking at central
facial features. The main difference between the gaze
behaviour of patients with autism and schizophrenia
and hereditary prosopagnosics appears to be the fact
that hereditary prosopagnosics do not avoid looking at
central features. Rather, in addition to the central
features they fixate external features and cover a
greater area of fixation. The dispersed gaze behaviour
observed in our results seems to be specific to heredi-
tary prosopagnosics.
Fig. 3 Fixations of a prosopagnosic and a participant of control
group 1 during a trial of the famous face task in which both of
them recognized the target face correctly. Crosses indicate
fixations (size corresponds to fixation length) and ellipse
indicates area that covered 83.35% of the fixations (Stark &
Ellis, 1981)
Fig. 4 Fixations of a prosopagnosic and a participant of control
group 2 during a trial of the unfamiliar face task in which both of
them recognized the target face correctly. Crosses indicate
fixations (size corresponds to fixation length) and ellipse
indicates the area that covered 83.35% of fixations (Stark &
Ellis, 1981)
Psychological Research
123
The findings of the present study can be related to
the way children recognize a face. For example,
Campbell, Walker and Baron-Cohen (1995) have
shown that young children tend to recognize
faces—unfamiliar faces in particular—better from their
external than their internal sections. Since the heredi-
tary prosopagnosics of the present study also included
information on the external parts of the faces in their
gaze behaviour this fact can be understood as a parallel
between children’s and hereditary prosopagnosics’ way
to process faces. Another parallel refers to the obser-
vation that children’s gaze behaviour is less focused
than that of adults when they were viewing faces
(Schwarzer, Huber & Du
¨
mmler, 2005). Thus, there
seem to be slight parallels between children’s and
hereditary prosopagnosics’ way to examine a face
visually. However, our results leave the question open
of whether the dispersed gaze of the hereditary pros-
opagnosics is specific to face processing only. In prin-
ciple, it is possible that hereditary prosopagnosics
exhibit a similar gaze pattern when viewing non-face
objects. This assumption, however, is not very likely
since until now there has been no empirical evidence of
any kind of object recognition impairment in heredi-
tary prosopagnosics. Nevertheless, this question needs
to be addressed in a further study. For now, it can be
stated that hereditary prosopagnosics show a different
gaze-orienting pattern as compared to controls. It is
also a task for a future project to test a larger sample of
hereditary prosopagnosics and to study to what extent
the analysis of gaze behaviour can serve as a method of
confirming the diagnosis of hereditary prosopagnosia.
Thus, our results show that not only there is a neu-
ronal processing pattern and face recognition perfor-
mance specific to congenital prosopagnosia but also a
certain gaze behaviour is associated with this impair-
ment. Even early perceptual processes concerning the
acquisition of facial information are sensitive to the
various processes that support face recognition. The
dispersed gaze of the hereditary prosopagnosics is
associated with a low face recognition performance.
Appendix
Faces used in the famous face task
Boris Becker
Norbert Blu
¨
m
George Bush
Sabine Christiansen
Bill Clinton
Gerard Depardieu
Lady Diana
Albert Einstein
Joschka Fischer
Greta Garbo
Thomas Gottschalk
Gu
¨
nther Grass
Gregor Gysi
Gu
¨
nther Jauch
Helmut Kohl
Oskar Lafontaine
Elvis Pressly
Claudia Roth
Gerhard Schro
¨
der
Ralf Schumacher
Ju
¨
rgen Trittin
Theodor Waigel
Richard von Weiza
¨
cker
Ulrich Wickert
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