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Available via license: CC BY-NC 3.0
Content may be subject to copyright.
I Spy With My Little Eye:
Typical, Daily Exposure to
Faces Documented From a
First-Person Infant Perspective
ABSTRACT: Exposure to faces is known to shape and change the face
processing system; however, no study has yet documented infants’ natural daily
first-hand exposure to faces. One- and three-month-old infants’ visual experience
was recorded through head-mounted cameras. The video recordings were coded
for faces to determine: (1) How often are infants exposed to faces? (2) To what
type of faces are they exposed? and (3) Do frequently encountered face types
reflect infants’ typical pattern of perceptual narrowing? As hypothesized, infants
spent a large proportion of their time (25%) exposed to faces; these faces were
primarily female (70%), own-race (96%), and adult-age (81%). Infants were
exposed to more individual exemplars of female, own-race, and adult-age faces
than to male, other-race, and child- or older-adult-age faces. Each exposure to
own-race faces was longer than to other-race faces. There were no differences in
exposure duration related to the gender or age of the face. Previous research
has found that the face types frequently experienced by our participants
are preferred over and more successfully recognized than other face types.
The patterns of face exposure revealed in the current study coincide with the
known trajectory of perceptual narrowing seen later in infancy. ß2013 The
Authors. Developmental Psychobiology Published by Wiley Periodicals, Inc. Dev
Psychobiol 56: 249–261, 2014.
Keywords: perceptual narrowing; face perception; development; infancy;
exposure to faces; head-mounted camera; other-race effect; other-
age effect
INTRODUCTION
Infants are born with the potential to adapt to their new
world and to adjust their sensory-perceptual systems to
fit their environment (Huttenlocher, 2002). As infants
learn what is relevant in their world, they improve their
ability to perceive relevant differences and show a
concomitant lack of improvement or decrement in their
ability to perceive irrelevant differences. Like directing
a beam of light from diffusely illuminating a room to
high-lighting a single item, as generalization declines,
specialization emerges. This experience-driven change
in perceptual ability during infancy has been termed
perceptual narrowing. Perceptual narrowing is evident
in multiple areas of learning within the first year of
life, including in speech perception (Kuhl et al., 2006),
cross-modal perception (Pons, Lewkowicz, Soto-Far-
aco, & Sebastian-Galles, 2009), and the perception of
music (Hannon & Trehub, 2005).
Perceptual narrowing is also evident in the domain
of face perception (Pascalis, de Haan, & Nelson, 2002).
Previous research has demonstrated that early experi-
ence shapes the development of the perceptual skills
and underlying neural architecture necessary to utilize
this highly important feature of the infant’s social
This is an open access article under the terms of the Creative
Commons Attribution-NonCommercial License, which permits use,
distribution and reproduction in any medium, provided the original
work is properly cited and is not used for commercial purposes.
Manuscript Received: 15 March 2013
Manuscript Accepted: 29 October 2013
Correspondence to: Nicole Sugden
Contract grant sponsor: Natural Sciences and Engineering Research
Council of Canada
Article first published online in Wiley Online Library
(wileyonlinelibrary.com): 28 November 2013
DOI 10.1002/dev.21183 ß2013 Wiley Periodicals, Inc.
Developmental Psychobiology
Nicole A. Sugden
Marwan I. Mohamed-Ali
Margaret C. Moulson
Department of Psychology
Ryerson University
350 Victoria Street, Toronto
Ontario, Canada M5B 2K3
E-mail: nsugden@ryerson.ca
world. Infants begin with a face processing system that
predisposes them to prefer faces over other visual
stimuli (Johnson, Dziurawiec, Ellis, & Morton, 1991;
Mondloch et al., 1999). Building on this preference,
infants show the ability to discriminate between faces
very early in life: 4-day-old infants discriminate and
prefer their mother’s face to the face of a stranger
(Pascalis, de Schonen, Morton, De Ruelle, & Fabre-
Grenet, 1995). This preference for the mother’s face is
dose-dependent; infants who receive more exposure to
their mother’s face during their first hours after birth
show a greater preference for their mother’s face
(Bushnell, 2001).
By 3 months of age, infants begin to demonstrate
systematic preferences for particular types of faces.
Three-month-old-infants prefer female faces over male
faces (Quinn, Yahr, Kuhn, Slater, & Pascalis, 2002),
own-race faces over other-race faces (Kelly
et al., 2005), and own-species faces over other-species
faces (DiGiorgio, Me
´ary, Pascalis, & Simion, 2012). At
7 months of age, infants show a preference for parent-
and infant-age faces over child-age faces (Sanefuji,
Ohgami, & Hashiya, 2005). These preferences seem to
be shaped by the particular experiences infants are
receiving, although no study has yet documented infant
experience. For example, Quinn et al. (2002) demon-
strated that the typical preference for female faces over
male faces is reversed when the infant has a male
primary caregiver. Although infants display preferences
for certain face types by 3 months of age, young infants
are generally equally facile at discriminating among
faces from multiple face categories, even those face
categories with which they have little experience. For
example, at 3 months of age infants are able to
discriminate between faces of races to which they have
had minimal exposure (Kelly et al., 2007) and at
6 months of age they can discriminate between faces of
species to which they have never been exposed (e.g.,
monkey faces; Pascalis et al., 2005).
By comparison, adults are less able or unable to
discriminate other-race faces (Hayward, Rhodes, &
Schwaninger, 2008) and other-species faces (Dufour,
Coleman, Campbell, Petit, & Pascalis, 2004; Pascalis
et al., 2002). As infants age, the early, broad tuning of
the perceptual system narrows progressively. By ap-
proximately 9 months of age, infants no longer show
the ability to discriminate between the types of faces
with which they have had no or little experience: 9-
month-old infants no longer show discrimination be-
tween other-species (Pascalis et al., 2005) and other-
race (Kelly et al., 2007) faces when tested with the
same procedures on which they were successful at
6 months. Additionally, studies using event-related
potentials (ERPs) reveal that in 9-month-old infants the
brain processes own-race and own-species faces differ-
ently than other-race and other-species faces (Balas,
Westerlund, Hung, & Nelson, 2011; Scott, Shannon, &
Nelson, 2006). This pattern of gradual behavioral and
neurological specialization for “own”-type faces pre-
sumably reflects the experiences with faces that infants
accumulate across the first year of life. Of yet, however,
it is unclear how much natural, daily exposure infants
receive to own- and other-face types in the first year,
whether there are large or small differences in expo-
sure, and how well these reflect typical patterns of
narrowing.
Although perceptual narrowing is observed in the
first year of life, the system is not inflexible; both
experimentally induced and natural changes in the
environment can alter the type of faces for which we
show proficiency. For example, infants who received
regular exposure to a picture book containing individu-
ally labeled other-species (monkey) faces from 6 to
9 months retained their ability to discriminate and
developed neural specialization for monkey faces (Scott
& Monesson, 2009, 2010). Here, experimental training
kept the perceptual window for discriminating other-
species faces open. Natural experience has also been
shown to re-open the perceptual window after infancy.
For example, Sangrigoli, Pallier, Argenti, Ventureyra,
and de Schonen (2005) demonstrated that Korean
children adopted into French families between 3 and
9 years of age showed a reversal in the other-race
effect; that is, these children became better able to
discriminate faces from their current culture (Caucasian
faces) relative to their ability to discriminate faces from
their previous home (Korean faces) (Sangrigoli
et al., 2005). In adulthood, experience allows adults to
become more proficient with face types that were
previously poorly discriminated. For example, adults
can develop facility with newborn (Macchi Cassia,
Picozzi, Kuefner, & Casati, 2009) or child (Harrison &
Hole, 2009) faces through daily at-work exposure to
these types of faces.
Since experience exerts a large influence on the
trajectory of perceptual narrowing, it has been hypothe-
sized that experience is what is ultimately driving the
development of the face processing system (Scott,
Pascalis, & Nelson, 2007). All experience is not equal,
with individuation of faces being key to “tune” the face
processing system (Scott & Monesson, 2009). From
this perspective, perceptual narrowing reflects adapta-
tion to salient perceptual inputs received from the
environment. Therefore, understanding the perceptual
inputs received by infants is key to understanding the
perceptual abilities and patterns of narrowing displayed
by infants. To examine whether the patterns of prefer-
ence and perceptual narrowing reflect the environment
250 Sugden et al. Developmental Psychobiology
in which infants develop, two studies have documented
infants’ early experiences and found support for an
environmental basis for both preference and perceptual
narrowing. Researchers monitoring infant–parent inter-
action after birth found a positive correlation between
the amount of exposure to the mother’s face and the
preference for mother (Bushnell, 2001). Additionally,
through parent report of infants’ natural daily exposure
to different face types, Rennels and Simmons (2008)
found that infants receive the most exposure to female,
parent-age, and parent-race faces, reflecting infants’
later patterns of ability in face discrimination.
These early studies documenting the face types seen
by infants represent a valuable first step in quantifying
and qualifying infants’ early exposure to faces. Howev-
er, recent work documenting the differences between
adult and child perspectives has called into question
whether an adult perspective can accurately portray
the visual experience of a child (Smith, Yu, &
Pereira, 2009). Smith and coworkers’ recent series of
studies documenting the first-person perspective of
adults and children clearly show that the visual
experiences of child and parent in the same interactive
context differ significantly. While a parent views the
world more globally, children view objects more locally
(Smith et al., 2009). For example, while playing with
their parents, children spend very little time looking at
their parent and much more time examining single
items up-close so that these items are large in the
child’s field of view. In contrast, parents spend much
more time looking at their child and monitoring the
entire scene in order to guide the interaction with their
child, and spend very little time with single items in
their field of view (Yoshida & Smith, 2008). Finally,
and most importantly, it is only the child perspective
that is predictive of learning in these parent-child
interactions, not the parent perspective (Yurovsky,
Smith, & Yu, 2013). Based on these findings, it seems
critical to document the typical daily face exposure of
the infant from the infant’s perspective. Therefore,
only observations collected from the infant perspective
can establish definitively whether perceptual narrowing
tracks the exposure to faces received during the first
year of life. Fortunately, technological advances have
made it possible to document the infant’s natural world
from a first-person infant perspective.
Here, we provide the first documentation of 1- and 3-
month-old infants’ natural daily exposure to faces
recorded from the perspective of the infant, through the
use of a head-mounted camera. This novel method of
capturing infants’ visual worlds was used to answer three
questions: (1) How often are infants exposed to faces? (2)
To what types of faces are they exposed? and (3) Do the
facestypestowhichtheyareexposedreflectthe
perceptual narrowing seen later in the first year of life?
We hypothesized that (1) infants would spend a large
proportion of their time exposed to faces, (2) they would
be exposed primarily to female, own-race, parent-age
faces, and (3) this pattern of exposure would be consistent
with infants’ abilities after perceptual narrowing.
METHOD
Participants
Fourteen 1-month-old (8 female) and 16 3-month-old (7
female) infant participants were recruited from a database of
parents who were interested in participating in developmental
research studies. We chose to test 1- and 3-month-old infants
to determine if face experience is biased both before any
behavioral markers of perceptual narrowing are evident (i.e.,
at 1 month of age) and before differences in discrimination
ability but after perceptual preferences for some face types
have emerged (i.e., at 3 months of age).
The average age at first visit of the 1-month-old group was
38 days (Range: 27–53 days). The average age at first visit of
the 3-month-old group was 98 days (Range: 90–118 days).
Infants in the 1-month-old group were Caucasian (9 infants),
Asian (2 infants), Black-Caucasian (1 infant), Southeast Asian
(1 infant), and Southeast Asian-Caucasian (1 infant). Infants in
the 3-month-old group were Caucasian (10 infants), Asian-
Caucasian (2 infants), Southeast Asian (1 infants), Asian (1
infant), Southeast Asian-Caucasian (1 infant), and Black-
Caucasian (1 infant). One-month-old infants spent an average
of 7 hr awake per day (M¼7.00 hr, Range: 3.5–12hr) while 3-
month-old infants spent an average of nearly 9hr awake per
day (M¼8 hr and 55 min, Range: 6.5–16hr). All parents were
of the same racial background as their infant (for infants with
two listed races, each parent belongs to one of the two listed
races). Parents of all of the infants were adults between the
ages of 20 and 45. Nearly all parents reported that their infants
had a female primary caregiver (their mother; 29 infants) and
one family reported that caretaking responsibilities for their 1-
month-old infant were shared equally by a male and female
primary caregiver (the mother and father).
Procedure
Each family was first visited in their home where parents
completed a demographics questionnaire, discussed privacy
issues related to video recording with a hidden camera, and
were shown how to operate the video camera. If the infant
was awake, parents turned the camera on, mounted the
camera on a headband, and placed the camera on their
infants’ head, with the experimenter providing guidance and
feedback as necessary. If the infant was not awake, parents
turned the camera on and mounted the camera on the
headband, with the experimenter going over in detail how to
place the camera on their infant’s head.
Parents were asked to place the camera on their infant’s
head whenever their infant was awake and alert and to
Developmental Psychobiology Infants’ Daily Exposure to Faces 251
remove the camera if the infant became fussy, fell asleep, or
the parent felt that the camera should be removed. To
facilitate parent and infant participation in this study, parents
were not given a minimum amount of time that the infant was
required to wear the camera, nor were parents given a
schedule for when to place the camera on the infant’s head.
Parents were asked to keep the camera for 2 weeks. On
average, parents kept the camera for 14 days (Range: 4–21
days) in the 1-month-old group and 13 days (Range: 6–21
days) in the 3-month-old group, after which either the
experimenter visited the family in their home to retrieve the
camera or the parents came to Ryerson University to return
the camera. All parents completed a final questionnaire
documenting their experience with the camera. Parents
received a copy of the video recorded from their infant’s
perspective and $25 for their participation.
A total of 44 hr and 47 min (M¼1 hr and 30 min per
participant, Range: 17 min to 4 hr and 22 min) of video were
recorded from the infants’ perspectives over an average of
13 days (Range: 4–21 days). One-month-olds contributed a
total of 19 hr and 43 min (M¼1 hr and 25 min per participant,
Range: 19 min to 4 hr and 44 min) of infant-perspective video
over an average of 14 days (Range: 4–21 days). Three-month-
olds contributed a total of 25 hr and 3 min (M¼1 hr and
34 min per participant, Range: 17 min to 4 hr and 22 min) of
infant-perspective video over an average of 13 days (Range:
6–21 days).
Places the infant participant was likely to visit during their
participation in the study was assessed during the initial
interview with parents, in the context of a conversation about
privacy concerns related to recording. All families stated that
the infant spent most of their time at home and all except for
three families said that they would be visiting at least one
other location (M¼1.85 non-home locations, Range: 0–4
non-home locations). Prior to each recording, parents com-
pleted a brief privacy questionnaire to remind them of privacy
issues related to recording; as part of this questionnaire they
reported the location in which recording began and ended.
The questionnaire data revealed that all parents reported
recording at home and most reported recording in at least two
non-home locations (M¼2.00 non-home locations, Range: 0–
7 non-home locations). One-month-olds typically were
recorded in at least one other location (M¼1.72 non-home
locations, Range: 0–7 non-home locations) while 3-month-
olds typically were recorded in at least two other locations
(M¼2.23 non-home locations, Range: 0–5 non-home loca-
tions). The three families who recorded only at home had
reported, in the initial interview, that they would not be
leaving the house with the infant except for doctor’s appoint-
ments, due to cultural tradition (two families) and sibling
illness (one family).
Equipment
A commercially available 4.7-cm-diameter DVR spy-camera
was used to record video. The camera had a smiley-face
printed on it; the camera looked similar to a happy-face pin
or button (see Fig. 1). This spy-camera was chosen because it
is small, lightweight, and designed to be inconspicuous (viz.
it does not look like a camera). The smiley-face camera,
specifically, was chosen because it looks very much like an
accessory designed for an infant; “cutesy” infant clothing
often includes large smiling faces. The camera was worn on
the infant’s head clipped to a fuzzy elasticized headband. To
ensure that the aperture of the camera sat above the bridge of
the infant’s nose and in-line with their eyebrows, the camera
was worn upside down. As a consequence, the smiley-face
was oriented upside-down. The camera captured 29 frames
per second and provided image resolution of 2048 1536
pixels. Video was recorded direct, in .AVI format, to a 16 GB
microSD memory card. While the camera recorded both
video and audio, only the video was used for the current
study. Parents were aware that the audio would not be used.
Coding and Reliability
All videos were coded second-by-second for faces of people
viewed in person by highly trained coders. For each face,
coders documented age, gender, and ethnicity. Non-human
faces (e.g., dog faces) and faces viewed on media (e.g., in
photographs or on television) were not included in the
analysis. All coders received at least 2 hr of orientation and
2 hr of one-on-one training with the experimenter, studied a
40-page coding guide, had at least 40 hr of video coding
experience coding three training videos, and achieved at least
85% reliability on all variables of interest on the last (28-min)
training video. The ages, genders, and races were known for
some faces in the first video and all of the faces in the second
training video. Therefore, the coders could be evaluated on
how well they estimated these variables. Coders for whom
reliability on one of these variables was below 85% received
FIGURE 1 Three-month-old infant wearing the happy-face
camera mounted on a headband. The lens of the camera is in
the left eye of the happy-face. The camera was worn upside-
down to ensure that the lens is nearer to the infant’s eyes, in
line with their eyebrows. Printed with permission of parent,
Dr. M. C. Moulson.
252 Sugden et al. Developmental Psychobiology
specific training on the variable they found difficult to
estimate.
All video recordings were spot-checked for video coding
accuracy by a lead coder with over 100 hr of coding
experience. Spot-checking was done to ensure that no faces
were missed because a coder was focusing on another face
that was present at the same time [viz. inattentional blindness
as described by Simons and Chabris (1999)]. If a random
spot-check found a face that was not included on the coding
sheet for a coded video, that video was re-coded from start to
finish. The video was then spot-checked again. Videos were
spot-checked and re-coded until spot-checking found no
missed faces. No video was re-coded more than twice due to
missed faces. All coders were made aware of the age, race,
and gender of the family members of the infant participant.
Ten percent of all participant videos (4hr and 43min)
were coded for all measures by a second coder. None of the
coders were aware if a video was going to be coded by a
second coder or if they were the second coder. The video
coding results produced by the first person to code the video
were included in the results. The results produced by the
second person to code the video were used only as a measure
of inter-rater reliability. There was high inter-rater reliability
for total amount exposure to all faces (a¼.998), female faces
(a¼.996), other-race faces (a¼.998), and other-age faces
(a¼.989). Considered a second way, raters’ mean level of
agreement per participant was 94% for face exposure (Range:
75–100%), 93% for female face exposure (Range: 82–100%),
96% for own-race face exposure (Range: 83–100%), and 95%
for adult-age face exposure (83–100%). That there was such a
high degree of agreement amongst the coders is partially
attributable to the fact that most infants saw a very restricted
range of faces and coders were aware of the age, gender, and
ethnicity of the faces most commonly seen by each infant,
those of the infant’s family members.
RESULTS
We expected that infants’ experiences with faces would
be highly variable and that our data would reflect this
high degree of variability. We examined adherence to
the assumptions of parametric statistical tests in the
overall dataset and between the 1- and 3-month-olds’
datasets for the following variables: overall exposure to
faces, exposure to female faces, exposure to own-race
faces, and exposure to adult-age faces. All variables
violated at least one assumption and most violated
multiple assumptions of parametric statistical tests.
Accordingly, all statistical tests reported below are non-
parametric tests.
Exposure to Real Faces
Of the total amount of video recorded, 11 hr and
24 min (25%) contained faces of humans who were
physically present in the infant’s environment. One-
month-olds were exposed to faces 25% of the time, and
3-month-olds were exposed to faces 26% of the time.
A Mann–Whitney test of the difference in exposure to
faces in 1-month-olds (Mdn ¼20%) and 3-month-olds
(Mdn ¼27%) was not statistically significant,
U¼109.00, z¼.125, p¼.918, r¼.02.
To capture a measure of the individual faces to
which infants are exposed that are potentially individu-
ated, we calculated the average number of faces of each
type present during each video. Since all interactions do
not provide equal opportunity to individuate faces, we
excluded videos in which infants were unlikely to
individuate the majority of faces present (i.e., visual
environments that contained more than 20 faces per
video—e.g., at the mall, walking down a busy street).
Eight videos (two 1-month-old videos and six 3-month-
old videos), with an average of 115 faces per video
(M¼115.25, Range: 23–315 faces per video), were
excluded from subsequent analyses of the number of
individual faces per video. Overall, infants were ex-
posed to an average of 2 faces (M¼2.19, Mdn ¼2.00,
Range: 1–19) per video. Both 1- and 3-month-olds were
exposed to an average of two faces (1-month-olds:
M¼1.92, Mdn ¼1.97, Range: 1–19; 3-month-olds:
M¼2.40, Mdn ¼2.00, Range: 1–10) per video, which
was not significantly different, Mann–Whitney test,
U¼71.50, z¼1.695, p¼.092, r¼.31.
On average, based on all videos (i.e., not excluding
videos with 20 or more faces), each face appeared in
the infant’s field of view for 4 s (M¼4.12 s per face,
Range: 1.89–8.90 s per face). This was true for both 1-
month-olds (M¼3.95 s per face, Range: 1.89–8.90 s
per face, Mdn ¼3.72 s per face) and 3-month-olds
(M¼4.27 s per face, Range: 2.44–6.15 s per face,
Mdn ¼4.30 s per face), with no significant difference
between the two age groups as confirmed by a Mann–
Whitney test, U¼84.00, z¼1.164, p¼.257, r¼.21.
Exposure to Own-Race Faces
We predicted that infants would be primarily exposed
to faces of their own race due to high levels of contact
with their primary caregiver and immediate family, as
reported by Rennels and Simmons (2008). This was
confirmed. Infants spent an overwhelming majority of
their time exposed to own-race faces (M¼96%, Range:
70–100%). Infants’ exposure to own-race faces (Mdn
¼100%) was significantly greater than their exposure
to other-race faces (Mdn ¼0%), as confirmed by a
Wilcoxon signed-ranks related-samples test, T¼0, Z¼
4.910, exact significance p<.001, r¼.90. That
infants were exposed to faces of their own race almost
exclusively was true for both 1-month-olds (M¼96%,
Range: 84–100%) and 3-month-olds (M¼96%, Range:
Developmental Psychobiology Infants’ Daily Exposure to Faces 253
70–100%). The majority of infants from each age group
(8 1-month-olds and 10 3-month-olds) were exposed
exclusively to own-race faces (see Fig. 2). A Mann–
Whitney test confirmed that there was no significant
difference between 1-month-olds’ (Mdn ¼100%) and
3-month-olds’ (Mdn ¼100%) exposure to own-race
faces, U¼108.00, z¼.19, p¼.868, r¼.03.
Infants were exposed to significantly more individual
own-race faces (M¼2.00, Mdn ¼2.00, Range: 0–15)
than individual other-race face (M¼.25, Mdn ¼.00,
Range: 0–4) per video, as confirmed by a Wilcoxon
signed-ranks paired-samples test, T¼1, Z¼4.406,
p<.001, r¼.80. Both 1-month-olds and 3-month-
olds were exposed to more individual own-race faces
(M¼1.86, Range: 0–15; and M¼2.12, Range: 0–8,
respectively) than individual other-race faces (M¼.04;
Range: 0–4; and M¼.43, Range: 0–4, respectively) per
video. A Mann–Whitney test confirmed that there was
no significant difference between 1-month-olds’ (Mdn
¼1.93 individual faces) and 3-month-olds’ (Mdn ¼2.00
individual faces) per video exposure to individual own-
race faces, U¼76.00, z¼1.511, p¼.135, r¼.28.
On average, infants were exposed to each own-race
face for significantly longer per face (M¼4.12 s,
Mdn ¼4.00 s, Range: 1.89–9.09 s) than each other-race
face (M¼1.43 s, Mdn ¼.00 s, Range: 0–11.50 s), as
confirmed by a Wilcoxon signed-ranks related-samples
test, T¼3, Z¼4.001, exact significance p<.001,
r¼.73. The difference remained even when infants
with no exposure to other-race faces were excluded
(M¼4.49 s per own-race face, Range: 2.94–9.09 s per
own-race face; M¼3.57 s per other-race face, Range:
1.52–11.50 s per own-race face).
The greater length of time exposed to each own-
versus other-race face was true both for 1-month-olds
(M¼4.06 s, Range: 1.89–9.09 s per own-race face;
M¼1.56 s, Range: 0–11.50 s per other-race face) and
for 3-month-olds (M¼4.18 s, Range: 2.44–6.15 s per
own-race face; M¼4.18 s, Range: 0–5.87 s per other-
race face). A Mann–Whitney test confirmed that there
was no significant difference between 1-month-olds’
(Mdn ¼3.94 s per face) and 3-month-olds’ (Mdn ¼4.12
s per face) exposure to own-race faces, U¼95.00,
z¼0.707, p¼.498, r¼.13.
Exposure to Female Faces
Since nearly all infants (n¼29) had a female primary
caregiver, we predicted that infants would spend more
time exposed to female faces than to male faces. As
expected, we found that infants spent more time
exposed to female than to male faces, with female
faces accounting for 70% of time spent with faces
across both age groups (Range: 7–100%). A Wilcoxon
signed-rank related-samples test confirmed that infants
are exposed to significantly more female (Mdn ¼76%)
than male (Mdn ¼24%) faces, T¼5, z¼3.469,
p<.001, r¼.63. Exposure to female faces was also
significantly different than a chance level of 50%, as
confirmed by a Wilcoxon signed rank test, T¼5,
Z¼3.754, p<.001, r¼.69.
That infants were exposed to primarily female faces
was true for both 1-month-old infants (M¼73%,
Range: 30–100%) and 3-month-old infants (M¼67%,
Range: 7–100%). One 3-month-old and one 1-month-
old were exposed exclusively to female faces (see
Fig. 3). A Mann–Whitney test confirmed that there was
FIGURE 2 Each participant’s percent exposure to own-race
faces. Each point represents one participant. Circles represent
1-month-old infant participants and triangles represent
3-month-old infant participants. Infants are ordered by age,
from youngest to oldest.
FIGURE 3 Each participant’s percent exposure to female
faces. Each point represents one participant. Circles represent
1-month-old infant participants and triangles represent
3-month-old infant participants. Infants are ordered by age,
from youngest to oldest.
254 Sugden et al. Developmental Psychobiology
no significant difference between 1-month-olds’ (Mdn
¼79%) and 3-month-olds’ (Mdn ¼73%) exposure to
female faces, U¼89.50, z¼.935, p¼.361, r¼.17.
Since there was large variability in infants’ exposure
to female faces, we examined the data of infants at
both the high (100% exposure to female faces) and low
(less than 50% exposure to female faces) ends of the
range to determine what factors might have influenced
these levels of exposure. Two infants received 100%
exposure to female faces. Both of these infants were
female. One 1-month-old spent 100% of her time
exposed to female faces. During the infant’s participa-
tion in this study, the father was working in a different
province. For this family, this was typical; the father
worked away from home for several months per year.
One 3-month-olds spent 100% of her time exposed to
female faces. The parents of this infant had separated
and the father was not living in the home at the time of
the study. The mother reported that the father had
infrequent contact with the infant (2 days per month).
Five infants received less than 50% exposure to
female faces. One male 3-month-old was exposed to
only 7% female faces. Although this infant had a
female primary caregiver (the mother), he spent a large
amount of time exposed to his own face in mirrors
(93% of his total time exposed to faces came from
exposure to his own face). The mother reported, and
the video confirmed, that the infant viewed himself in
mirrors while on his play mat, while in his car seat,
and while being carried by his mother. The mother
reported that he found this engaging and that she would
put him in front of a mirror when he was distressed,
since seeing himself would often soothe him. If this
participant’s exposure to his own face is excluded, then
exposure to female faces accounted for 96% of all
remaining face exposure. One male 1-month-old was
exposed to only 30% female faces. The parents of this
infant reported sharing parenting responsibilities equal-
ly. One 3-month-old male infant was exposed to 39%
female faces. This infant had an older male sibling and
spent 50% of his time exposed to young faces (includ-
ing both his own and that of his brother). One 3-month-
old female infant was exposed to 44% female faces.
This infant had an older male sibling with whom she
spent 24% of her time. A second 3-month-old female
infant was exposed to 49% female faces, but parental
report did not clarify why this infant received lower-
than-expected exposure to female faces.
Since the infants with the lowest three scores for
female face exposure were male and all of the infants
with very high female face exposure (100%) were
female, we examined the data to determine whether
there was a systematic difference between male and
female infants’ exposure to male and female faces.
Irrespective of age, we found that female infants’
exposure to female faces was higher (M¼73%) than
was male infants’ (M¼65%). However, a Mann–
Whitney test revealed no significant difference between
females’ (Mdn ¼76%) and males’ (Mdn ¼73%) expo-
sure to female faces, U¼93, z¼.809, p¼.430,
r¼.15.
Infants were exposed to significantly more individu-
al female faces (M¼1.40; Mdn ¼1.31, Range: .93–
3.00) than individual male faces (M¼.83; Mdn ¼.74,
Range: 0–5) per video, as confirmed by a Wilcoxon
signed-ranks paired-samples test, T¼2, Z¼3.577,
p<.001, r¼.65. One-month-olds and 3-month-olds
were both exposed to more individual female faces
(M¼1.31, Range: .93–2.25; and M¼1.48, Range: 0–5,
respectively) than individual male faces (M¼.64,
Range: 1.00–3.00; and M¼.98, Range: 0–5, respective-
ly) per video. A Mann–Whitney test confirmed that
there was no significant difference between 1-month-
olds’ (Mdn ¼1.24 individual faces) and 3-month-olds’
(Mdn ¼1.48 individual faces) per-video exposure to
female faces, U¼90.50, z¼.900, p¼.379, r¼.16.
On average, infants were exposed to each female
face (M¼3.94 s, Mdn ¼3.91 s, Range: 2.03–9.88 s per
face) and each male face (M¼4.15 s, Mdn ¼3.83 s,
Range: 0–10.81 s per face) for approximately the same
amount of time, 4 s. The difference between genders
was not significant, as confirmed by a Wilcoxon
signed-rank related-samples test, T¼0, Z¼.072,
p¼.952, r¼.01. One-month-olds and 3-month-olds
spent similar amounts of time exposed to each female
face (M¼3.79 s, Range: 2.03–9.88 s per face; and
M¼4.06 s, Range: 2.31–6.64 s per face, respectively)
as each male face (M¼1.56 s, Range: 0–11.50 s per
face; and M¼4.52 s, Range: 0–10.81 s per face,
respectively). A Mann–Whitney test confirmed that
there was no significant difference between 1-month-
olds’ (Mdn ¼3.13 s per face) and 3-month-olds’ (Mdn
¼4.25 s per face) exposure to female faces, U¼80.00,
z¼1.330, p¼.193, r¼.24.
Exposure to Adult-Age Faces
We predicted that infants would spend the majority of
their time exposed to their caregivers; thus, we
expected that infants would be exposed primarily to
adult-age faces (aged 20–49 years). The data confirmed
this prediction. Infants spent the majority of their time
exposed to adult-age faces (M¼81%, Range: 7–100%).
There was a statistically significant difference between
adult-age (Mdn ¼92%) and not-adult-age (all faces not
20–49 years old) (Mdn ¼10%) face exposure, as
confirmed by a Wilcoxon signed-ranks paired-samples
test, T¼3, Z¼4.228, p<.001, r¼.77.
Developmental Psychobiology Infants’ Daily Exposure to Faces 255
One-month-old infants spent 91% of their time
exposed to adult-age faces (Range: 61–100%), with 2
of 14 infants spending 100% of their time exposed to
adult-age faces (see Fig. 4). Three-month-old infants
spent 73% of their time exposed to adult-age faces
(Range: 7–100%), with 3 of 13 infants spending 100%
of their time exposed to adult-age faces. A Mann–
Whitney test confirmed that there was no significant
difference between 1-month-olds’ (Mdn ¼94%) and 3-
month-olds (Mdn ¼80%) exposure to adult-age faces,
U¼89.50, z¼.935, p¼.361, r¼.17.
Infants were exposed to an average of 1–2 individual
adult-age faces (M¼1.45, Range:0–13) and less than 1
individual not-adult-age face (M¼.71, Range: 0–6) per
video. The difference between per-video exposure to
adult-age (Mdn ¼1.50 individual faces) and not-adult-
age (Mdn ¼.50 individual faces) faces was statistically
significant, as confirmed by a Wilcoxon signed-ranks
paired-samples test, T¼4, Z¼3.380, p<.001, r¼
.62. One- and three-month-olds were exposed to
similar numbers of individual adult-age (M¼1.55,
Range: 0–13; and M¼1.36, Range: 0–6, respectively)
and not-adult-age (M¼.39, Range: 0–6; and M¼.97,
Range: 0–5, respectively) faces per video. A Mann–
Whitney test confirmed that there was no significant
difference between 1-month-olds’ (Mdn ¼1.57) and 3-
month-olds’ (Mdn ¼1.38) per-video exposure to adult-
age faces, U¼97.00, z¼.625, p¼.544, r¼.11.
On average, infants’ per face length of exposure to
each adult-age face (M¼3.98 s, Mdn ¼3.87 s, Range:
.00–9.17 s) was not significantly different than their per
face length of exposure to each not-adult-age face
(M¼3.68 s, Mdn ¼3.17 s, Range: .00–12.00 s), as con-
firmed by a Wilcoxon signed-ranks paired-samples test,
T¼0, Z¼.792, p¼.440, r¼.14. One- and three-
month-olds had similar per face length of exposure to
each individual adult-age face (M¼4.06 s, Range:
1.89–9.17 s; and M¼3.90 s, Range: .00–6.10 s, respec-
tively) and not-adult-age-face (M¼3.77 s, Range: .00–
12.00 s; and M¼3.60 s, Range: .00–7.03 s). A Mann–
Whitney test confirmed that there was no significant
difference between 1-month-olds’ (Mdn ¼3.68 s) and
3-month-olds (Mdn ¼4.09 s per face) exposure to
adult-age faces, U¼103.00, z¼.374, p¼.728, r¼
.07.
DISCUSSION
The current study is the first to document infants’
natural daily exposure to faces from the perspective of
the infant. Consistent with theoretical perspectives that
emphasize the role of learning in the development of
face perception (e.g., Gauthier & Tarr, 2002;
Nelson, 2001), our results reveal that faces are a
common and frequent part of the infant visual world.
One-month-olds spent 25% of their recorded waking
hours exposed to faces. Three-month-olds spent 26% of
their recorded waking hours exposed to faces. Given
this massive exposure to faces, it is not surprising that
infants quickly become proficient with this class of
visual stimuli. Our results are congruent with previous
studies that have attempted to document face exposure
in infancy (e.g., Rennels & Simmons, 2008), but goes
beyond previous research in two ways. First, by
documenting infants’ exposure to faces from a first-
person perspective, we can be certain that the results
reported here reflect the infant’s true experience with
faces, something that is not possible from results
collected from the adult’s perspective (Smith
et al., 2009). Second, by documenting infants’ exposure
to faces at 1 and 3 months of age, the current study
characterizes the very early experiences that shape later
perceptual development. Infants at 1 and 3 months of
age have not undergone perceptual narrowing of any
kind, but by 3 months they begin showing preferences
for faces of certain categories (e.g., own-race, Kelly
et al., 2005), a potential precursor to perceptual
narrowing. By examining these two age groups, this
study can characterize the influences that may be
driving preference and later differential ability.
The current data represent the normal, daily experi-
ences of our infant participants. The video data
collected were rich and highly variable. Most was
filmed at the family home, representing the environ-
ment in which parents reported that infants spent the
most time, and captured activities such as playing with
FIGURE 4 Each participant’s percent exposure to adult-age
faces. Each point represents one participant. Circles represent
1-month-old infant participants and triangles represent
3-month-old infant participants. Infants are ordered by age,
from youngest to oldest.
256 Sugden et al. Developmental Psychobiology
parents, playing with siblings, watching parents go
about household chores (cooking, cleaning), being
changed, and being fed. The video data also included
outside-of-the-home destinations and activities, such as
mommy-and-me groups, library reading groups, shop-
ping, walking outside (in a stroller, car-seat, sling,
chest-carrier, etc.), grandparents’ and friends’ homes,
father’s workplace, sibling’s dance recital, and dinner
in a restaurant. The activities in which infants and
caregivers engaged during these videos included times
during which they were not interacting (e.g., infant
passively watching a mobile, with the caregiver not
visible), intermittent interactions (e.g., the caregiver
engaged in a discussion with a friend or pushing a
pram in a shopping mall while regularly pulling faces
at their infant), and involved interactions (e.g., reading
a book to, playing with objects with, introducing new
people to, engaging in song-and-dance games with,
feeding, and changing the infant). Analyzing how
particular types of activities influence infants’ visual
experiences would be a rich area for future research.
While it is possible that these data may not be fully
representative of infant’s experiences due to parents
selecting when to record and due to the camera
potentially influencing the behavior of the people being
recorded, we believe that our study captures the typical
daily experiences of our participants for several rea-
sons. First, the videos captured do reflect the locations
in which, in the initial interview, parents anticipated
being or visiting; the parents who anticipated recording
only at home did record only at home, while parents
who expected to be attending non-home locations with
their infants did record at non-home locations. Second,
the experiences and activities recorded varied widely
and included age-typical interactions for 1- and 3-
month-old infants (e.g., feeding, changing, playing).
Third, while it is difficult to assess whether adults
changed their behavior during their interaction with an
infant wearing a camera, we suspect that any alterations
in adult behavior were minimal. This is primarily
because, unless they were informed about the study,
most adults would not be aware that the infant was
wearing a camera. The smiley-face spy camera was
selected for this reason—it is very small and is similar
to typical infant accessories. Finally, some parents
spontaneously reported when they were returning the
camera that, during recording, they and their family
would forget that the infant was wearing a camera;
candid sections of video seem to corroborate these
statements.
Infants not only receive a large amount of exposure
to faces, they also receive a disproportionate amount of
exposure to some face types and little or no exposure
to other face types. This disproportionate exposure to
particular face types manifests in the total proportion of
time spent exposed to those face types, the number of
individual exemplars of those face types seen, and the
amount of time spent with each individual exemplar of
those face types. Not unexpectedly, this disproportion-
ate exposure reflects the makeup of each infant’s home
environment rather than the broader community in
which the infants live.
Own-race faces were the most commonly experi-
enced face types (96% of all faces) despite infants’
being of a variety of different backgrounds (i.e., own-
race represents Caucasian, Asian, Southeast Asian,
Asian and Caucasian, Southeast Asian and Caucasian,
and Black and Caucasian). This is similar to the 92%
exposure to own-race faces reported by Rennels and
Simmons (2008). Eighteen of 30 infants (8 1-month-
olds and 10 3-month-olds) were exposed exclusively to
own-race faces. Our infant participants were, on aver-
age, more than 25 times more likely to be exposed to
the face of an own-race individual than the face of an
other-race individual (M¼.07 individual other-race
faces and M¼1.88 individual own-race faces per
video) and, if exposed to an other-race face, they spent
less time exposed to that particular face (M¼1.43 and
4.12 s per face, respectively). All of the infants who
participated in this study lived in metropolitan Toronto,
a highly multicultural city with a diverse population.
The largest visible racial group is Caucasians, who
account for only 42% of the population (Statistics
Canada, 2006). Against this backdrop of diversity, it is
even more striking that infants were exposed nearly
exclusively to own-race faces.
This predominant exposure to own-race faces in
early infancy parallels the pattern of perceptual nar-
rowing for other-race faces that has been well docu-
mented in previous studies. By 3 months of age,
infants demonstrate a preference for own-race faces
(Kelly et al., 2007); by 6 months of age, infants
demonstrate reduced ability to discriminate between
faces in certain other-race categories (Kelly
et al., 2009); and by 9 months of age, when tested with
the same procedure, infants demonstrate behavioral
evidence of perceptual narrowing, maintaining only the
ability to discriminate among faces belonging to their
own racial group (Kelly et al., 2009). Infants show a
similar pattern of perceptual narrowing for other-
species faces, with 6-month-olds showing equal facility
discriminating human and monkey faces, and 9-month-
olds showing diminished ability to discriminate mon-
key faces (Pascalis et al., 2002).
Previous work has demonstrated that it is possible to
keep the perceptual window for processing “other”
faces open between 6 and 9 months of age. Scott and
Monesson (2009) exposed 6-month-old infants to a
Developmental Psychobiology Infants’ Daily Exposure to Faces 257
picture book containing six other-species faces (i.e.,
monkey faces) for 10 min per day over the first 2 weeks
of the study, then with decreasing frequency thereafter.
This limited exposure to monkey faces was sufficient to
keep the perceptual window open, such that infants
who received this exposure were still able to discrimi-
nate monkey faces at 9 months of age. Limited
exposure to other-race faces has also been found to
keep the perceptual window open for these types of
faces in infants trained between the ages of 6–9 months
(Heron-Delaney et al., 2011) and in infants trained for
three weeks between the ages of 8–10 months (Anzures
et al., 2012). Therefore, the perceptual narrowing for
other-race faces found in 9-month-old infants (Kelly
et al., 2009) suggests that infants receive a dearth of
exposure to other-race faces. Indeed, our results support
that supposition in three ways: (1) infants in the current
study received nearly exclusive exposure to own-race
faces, (2) they were exposed to more own-race
individuals, and (3) they spent more time per face
exposed to these highly-available own-race faces.
Infants were primarily exposed to female faces
(70% of all face exposure was female face exposure).
Based on this differential exposure, we suggest that
gender may be an area in which perceptual narrowing
operates early and reflects infants’ disproportionate
exposure to female faces. Although gender has not
typically been considered a domain of perceptual
narrowing, the development of infant preference for
and superior recognition of female faces (Quinn
et al., 2002) mirrors early preference for and discrimi-
nation of own-race faces (Kelly et al., 2005, 2007). If
perceptual narrowing is considered a progressive pro-
cess, then early preference for the face-types with
which infants have received the most experience might
reflect early tuning of the perceptual system to the most
common face type—that is, preference for the face
types with which infants have the most experience may
be an early marker of experience-based perceptual
narrowing.
In the case of gender, it is surprising that infants do
not show equal ability with both male and female faces
(Fagan, 1976; Quinn et al., 2002), given that our data
demonstrate a significant amount of exposure to male
faces (on average, 30% of the faces seen by infants are
male faces) and no significant difference in length of
exposure per face. The key difference appears to be
that there are simply fewer male faces available in
infants’ visual worlds. From Scott and Monesson’s
(2009) training study, it is clear that the perceptual
window for ‘other’ faces can be held open with
surprisingly little exposure, as long as the exposure
involves individuation of face exemplars. However, it is
still uncertain what minimum number of exemplars or
minimum amount of time is required for infants to
maintain facility with “other” face categories, and it is
possible that the male face exposure received by most
infants does not meet the criteria. Our data suggests
that, on average, infants did see significantly more,
nearly twice as many, individual female faces than
male faces (M¼1.37 and .73 faces per video, respec-
tively). If infants receive exposure to very few male
faces (e.g., only father), it is possible that infants’
exposure to male faces does not individuate those male
faces, that there are too few individual male face
exemplars, or infants’ attention is not being equally
captured by male and female faces. All of these factors
could potentially lead to decreased facility with male
faces than female faces. Directly linking natural expo-
sure to male faces to early preferences for female over
male and later discrimination of female and male faces
would help to resolve this issue. An analysis of how
males and females may interact differently with infants
in natural situations, in combination with eye-tracking
data capturing infant visual attention during these
interactions, may also yield insight into what factors
drive differential tuning of the perceptual system to
male and female faces.
Infants were primarily exposed to adult-age faces
(81% of all face exposure was to adult-age faces). This
level of exposure suggests a third area in which
perceptual narrowing may be operating. Due to a lack
of research that has directly investigated this question
in infants, it is unclear whether infants prefer adult-age
faces and/or show superior discrimination of adult-age
faces over other-age faces. One study compared 7-
month-olds’ preference for infant, child, and adult faces
as measured by visual preference and behavioral
response (i.e., table-banging) (Sanefuji et al., 2005).
They found only a small visual preference for infant
over child faces and increased table-banging in re-
sponse to both adult and infant faces. In childhood, the
evidence is mixed: there is evidence for both a
perceptual bias for child-age faces (i.e., children show
superior recognition for faces within two years of their
chronological age compared to younger and older
faces; Hills & Lewis, 2011), and a perceptual bias for
adult-age faces (i.e., children show superior recognition
for adult faces compared to children’s faces; Macchi
Cassia, Pisacane, & Gava, 2012). There is also a clear
adult-age bias in adulthood, as adults are better able to
recognize adult faces than children’s faces (Anastasi &
Rhodes, 2006).
Macchi Cassia (2011) hypothesizes that an “other-
age effect,” similar to the other-race effect, will be
found in infancy. Based on our data, if total exposure
time is driving the bias, we predict that this will
manifest as an adult-age bias in infancy, with 3-month-
258 Sugden et al. Developmental Psychobiology
old infants preferring adult-age faces, and that this
adult-age bias will be slightly more robust than the
preference for female faces (e.g., Quinn et al., 2002)
and less robust than the preference for other-race faces
(e.g., Kelly et al., 2007), due to exposure to adult-age
faces (81%) being higher than exposure to female faces
(70%) but lower than exposure to own-race faces
(96%) in the current study. At 9 months, infants should
also demonstrate a reduced ability to discriminate
child-age or infant-age faces. In other words, the
perceptual window for processing faces of all different
ages would narrow as it does for other-race and male
faces. If individual exemplars or exposure time per
face, however, is key to perceptual narrowing, then the
majority of infants should show no adult-age bias
provided that they are receiving, similar to our partic-
ipants, exposure to equal numbers of adult-age and not-
adult age individuals and spending an equivalent
amount of time exposed to both of these face types on
a per face basis. Future research should examine
preferences for and discrimination ability with adult-
age versus infant-, child-, and older-adult-age faces in
3-, 6-, and 9-month-old infants in order to explore these
predictions.
While the pattern of exposure to different face types
was consistent with our predictions, there were differ-
ences between the groups and individual differences
among infants. Despite similar proportions of time
spent exposed to faces (26% and 25%, respectively),
since 3-month-old infant participants spent more time
awake (M¼8 hr and 55 min awake per day) than 1-
month-old participants (M¼7 hr awake per day), their
absolute level of exposure was different. It is unclear
how these differences in exposure may influence
infants’ learning at each age; specifically, it is currently
unknown what feature(s) of face exposure drives
perceptual narrowing (i.e., is it the proportion of time
exposed to particular face types or is there some
minimum level of exposure that ensures facility with a
particular face type). As depicted in Figures 2–4, while
most infants were exposed primarily to adult-age, own-
race, female faces, some infants were exposed to a
more heterogeneous sampling of face types. While we
have suggested that patterns of homogeneous face
exposure are congruent with known patterns of percep-
tual narrowing, the current study cannot speak directly
to how this exposure influences infants’ later abilities.
This open question leads to a new line of inquiry that
can be investigated using the powerful first-person
perspective methodology used in the current study: the
relations between individual differences in early experi-
ence and individual differences in later perceptual
ability. Within individual differences, a longitudinal
study would allow for an investigation of the stability
or variability in these differences within an individual.
A second opportunity afforded by this methodology is
the examination of cultural differences in early experi-
ences and, similarly, how these relate to later perceptual
ability.
A first-person perspective provides researchers with
the opportunity to understand whether individual
infants or cultural populations of infants who receive
more own-race, adult-age, or female face exposure
show greater reductions in the ability to discriminate
the “other” face types. It also allows for the description
of other factors, beyond mere exposure, that may
influence infants’ later performance. For example,
Yurovsky Fricker, Yu, and Smith (2013) have docu-
mented that greater proximity and fewer competing
visual stimuli in the visual field facilitate learning.
Scott and Monesson (2009) have reported that individu-
ation of exemplars maintains perceptual discrimination
while mere exposure does not. Exploring relations
between particular aspects of face exposure and varia-
tions in perceptual ability through the use of the first-
person perspective methodology can lead to an in-
creased understanding of the precise facets of exposure
that drive perceptual narrowing in the domain of face
perception. Expanding beyond the domain of face
perception, understanding early, natural, daily experi-
ences of infants would permit a better understanding of
factors that influence later development in multiple
diverse areas, such as motor or language development.
Overall, our results suggest that the exposure to
faces received by infants at 1 and 3 months of age
mirrors the pattern of perceptual narrowing across three
different face characteristics—race, gender, and age.
Though this study did not directly examine the relation-
ship between exposure and ability, it offers a powerful
tool that can be used to quantify natural, daily, face
exposure for future studies directly assessing this
relationship. Infants spend one-quarter (25%) of their
waking hours exposed to faces. This massive exposure
does not provide equal representation of all face types;
rather, young infants see primarily female, adult-age,
own-race faces. This study is the first to document the
quantity and quality of infants’ natural daily face
exposure from the infant’s perspective, and offers
strong support for the idea that experience drives the
development of the face processing system.
NOTES
We thank Ameera Ali, Andrea Andrei, Nina Arcon, Ajani
Asokumar, Rafael Baguinan, Pavanpreet Bhardwaj, Jamie
Lynn Juarez, Alyssa Gagnon, Yumna Gulzar, Zoe Kornhauser,
Andrea Kusec, Shara Nauth, Bessie Orfanakos, Angelica
Developmental Psychobiology Infants’ Daily Exposure to Faces 259
Rojas, Kristina Safar, Nirosini Thanabalasingam, Vaunam
Venkadasalam, and Lan (Mary) Wei for their dedication,
commitment, and hours of hard work helping to code the data.
We thank Dr. Benjamin Balas for his input during the
preparation of this manuscript. This research was supported
by a grant from the Natural Sciences and Engineering Research
Council of Canada to M. Moulson.
REFERENCES
Anastasi J. S., & Rhodes, M. G. (2006). Evidence for an
own-age bias in face recognition. North American Journal
of Psychology, 8(2), 237–252.
Anzures, G., Wheeler, A., Quinn, P. C., Pascalis, O., Slater,
A. M., Heron-Delaney, M., … Lee, K. (2012). Brief daily
exposure to Asian females reverses perceptual narrowing
for Asian faces in Caucasian infants. Journal of Experi-
mental Child Psychology, 112(4), 484–495. doi: 10.1016/j.
jecp.2012.04.005
Balas, B., Westerlund, A., Hung, C., & Nelson, C. A. III.
(2011). Shape, color, and the other-race effect in the infant
brain. Developmental Science, 14(4), 892–900. doi:
10.1111/j.1467-7687.2011.01039.x
Bushnell, I. W. R. (2001) Mother’s face recognition in
newborn infants: Learning and memory. Infant and Child
Development, 10, 67–74. doi: 10.1002/icd.248
DiGiorgio, E., Me
´ary, D., Pascalis, O., & Simion, F. (2012).
The face perception system becomes species-specific at
three months: An eye-tracking study. International Journal
of Behavioral Development, 37(2), 95–99. doi: 10.1177/
0165025412465362
Dufour, V., Coleman, M., Campbell, R., Petit, O., & Pascalis,
O. (2004). On the species-specificity of face recognition in
human adults. Current Psychology of Cognition, 22(3),
315–333.
Fagan, J. F. (1976). Infants’ recognition of invariant features
of faces. Child Development, 47, 627–638. Stable URL:
http://www.jstor.org/stable/1128177.
Gauthier I., & Tarr, M. J. (2002). Unraveling mechanisms for
expert object recognition: Bridging brain activity and behav-
iour. Journal of Experimental Psychology: Human Perception
and Performance, 28(2), 431–446. doi: 10.1.1.20.5290
Hannon E. E., & Trehub, S. E. (2005). Metrical categories in
infancy and adulthood. Psychological Science, 16, 48–55.
doi: 10.1111/j.0956-7976.2005.00779.x
Harrison V., & Hole, G. J. (2009). Evidence for a contact-
based explanation of the own-age bias in face recognition.
Psychonomic Bulletin & Review, 16, 264–269. doi:
10.3758/PBR.16.2.264
Hayward, W. G., Rhodes, G., & Schwaninger, A. (2008). An
own-race advantage for components as well as configura-
tions in face recognition. Cognition, 106, 1017–1027. doi:
10.1016/j.cognition.2007.04.002
Heron-Delaney, M., Anzures, G., Herberg, J. S., Quinn, P. C.,
Slater, A. M., Tanaka, J. W., … Pascalis, O. (2011).
Perceptual training prevents the emergence of the other
race effect during infancy. PLoS ONE, 6(5), e19858. doi:
10.1371/journal.pone.0019858
Hills P. J., & Lewis, M. B. (2011). The own-age face
recognition bias in children and adults. Quarterly Journal
of Experimental Psychology, 64(1), 17–23. doi: 10.1080/
17470218.2010.537926
Huttenlocher, P. R. (2002) Neural plasticity: The effects of
environment on the development of the cerebral cortex.
Cambridge, MA: Harvard University Press.
Johnson, M. H., Dziurawiec, S., Ellis, H., & Morton, J.
(1991). Newborns’ preferential tracking of face-like stim-
uli and its subsequent decline. Cognition, 40, 1–19. doi:
10.1016/0010-0277(91)90045-6
Kelly, D. J., Liu., S., Lee., K., Quinn, P. C., Pascalis, O.,
Slater, A. M., & Ge, L. (2009). Development of the other-
race effect during infancy: Evidence towards universality?
Journal of Experimental Child Psychology, 104, 105–114.
doi: 10.1016/j.jecp.2009.01.006
Kelly, D. J., Quinn, P. C., Slater, A. M., Lee, K., Ge, L., &
Pascalis, O. (2007). The other-race effect develops during
infancy: Evidence of perceptual narrowing. Psychological
Science, 18, 1084–1089. doi: 10.1111/j.1467-9280.2007.
02029.x
Kelly, D. J., Quinn, P. C., Slater, A. M., Lee, K., Gibson, A.,
Smith, M., Ge, L., & Pascalis, O. (2005). Three-month-
olds, but not newborns, prefer own-race faces. Develop-
mental Science, 8, F31–F36. doi: 10.1111/j.1467-
7687.2005.0434a.x
Kuhl, P. K., Stevens, E., Hayashi, A., Deguchi, T., Kiritani,
S., & Iverson, P. (2006). Infants show a facilitation effect
for native language phonetic perception between 6 and 12
months. Developmental Science, 9(2), F13–F21. doi:
10.1111/j.1467-7687.2006.00468.x
Macchi Cassia, V. M. (2011) Age biases in face processing:
The effects of experience across development. British
Journal of Psychology, 4, 816–882. doi: 10.1111/j.2044-
8295.2011.02046.x
Macchi Cassia, V., Picozzi, M., Kuefner, D., & Casati, M.
(2009). Why mix-ups don’t happen in the nursery. Evidence
for an experience-based interpretation of the other-age
effect. The Quarterly Journal of Experimental Psychology,
62, 1099–1107. doi: 10.1080/1747021080261 7654
Macchi Cassia, V., Pisacane, A., & Gava, L. (2012). No own-
age bias in 3-year-old children: More evidence for the role
of early experience in building face-processing biases.
Journal of Experimental Child Psychology, 113(3), 372–
382. doi: 10.1016/j.jecp.2012.06.014
Mondloch, C. J., Lewis, T. L., Budreau, D. R., Maurer, D.,
Dannemiller, J. L., Stephens, B. R., & Kleiner-Gathercoal,
K. A. (1999). Face perception during early infancy.
Psychological Science, 10, 419–422. doi: 10.1111/1467-
9280.00179
Nelson, C. A. (2001) The development and neural bases of
face recognition. Infant and Child Development, 10, 3–18.
doi: 10.1.1.130.8912
Pascalis, O., de Haan, M., & Nelson, C. A. (2002). Is face
processing species-specific during the first year of life?
Science, 296, 1321–1323. doi: 10.1126/science.1070223
Pascalis, O., de Schonen, S., Morton, J., Deruelle, C., &
Fabre-Grenet, M. (1995). Mother’s face recognition by
260 Sugden et al. Developmental Psychobiology
neonates: A replication and an extension. Infant Behaviour
and Development, 18, 79–85. doi: 10.1016/0163-6383(95)
90009-8
Pascalis, O., Scott, L. S., Kelly, D. J., Shannon, R. W.,
Nicholson, E., Coleman, M., & Nelson, C. A. (2005).
Plasticity of face processing in infancy. Proceedings of the
National Academy of Sciences of the United States of
America, 102(14), 5297–5300. doi: 10.1073/pnas.04066
27102
Pons, F., Lewkowicz, D. J., Soto-Faraco, S., & Sebastia
´n-
Galle
´s, N. (2009). Narrowing of intersensory speech
perception in infancy. Proceedings of the National Acade-
my of Sciences of the United States of America, 106(26),
10598–10602. doi: 10.1073/pnas.0904134106
Quinn, P. C., Yahr, J., Kuhn, A., Slater, A. M., & Pascalis, O.
(2002). Representation of the gender of human faces by
infants: A preference for female. Perception, 31(9), 1109–
1121. doi: 10.1068/p3331
Rennels J. L., & Simmons, R. E. (2008). Facial experience
during the first year. Infant Behavioral Development,
31(4), 665–678. doi: 10.1016/j.infbeh.2008.04.009
Sanefuji, W., Ohgami, H., & Hashiya, K. (2005). Infants’
preference for infants and adults. Proceedings of 2005 4th
IEEE International Conference on Development and
Learning, 93–95. doi: 10.1109/DEVLRN.2005.1490950
Sangrigoli, S., Pallier, C., Argenti, A.-M., Ventureyra, V. A.
G., & deSchonen, S. (2005). Reversibility of the other-
race effect in face recognition during childhood. Psycho-
logical Science, 16(6), 440–444. doi: 10.1111/j.0956-
7976.2005.01554.x
Scott, L. S., & Monesson, A. (2010). Experience dependent
neural specialization during infancy. Neuropsychologia,
48, 1857–1861. doi: 10.1016/j.neuropsychologia.2010.02.
008
Scott L. S., & Monesson, A. (2009). The origin of biases in
face perception. Psychological Science, 20, 676–680. doi:
10.1111/j.1467-9280.2009.02348.x
Scott, L. S., Pascalis, O., & Nelson, C. A. (2007). A domain-
general theory of the development of perceptual discrimi-
nation. Current Directions in Psychological Science, 16,
197–201. doi: 10.1111/j.1467-8721.2007.00503.x
Scott, L. S., Shannon, R. W., & Nelson, C. A. (2006). Neural
correlates of human and monkey face processing in 9-
month-old infants. Infancy, 10(2), 171–186. doi: 10.1207/
s15327078in1002_4
Simons D. J., & Chabris, C. F. (1999). Gorillas in our midst:
Sustained inattentional blindness for dynamic events.
Perception, 28(9), 1059–1074. doi: 10.1068/p2952
Smith, L. B., Yu, C., & Pereira, A. F. (2009). Not your
mother’s view: The dynamics of toddler visual experience.
Developmental Science, 14(1), 9–17. doi: 10.1111/j.1467-
7687.2009.00947.x
Statistics Canada. (2006). Visible minority population by
census metropolitan area: 2006 Census: Kingston, Peter-
borough, Oshawa, Toronto, Hamilton. Retrieved from
http://www.statcan.gc.ca/tables-tableaux/sum-som/l01/
cst01/demo53c-eng.htm.
Yoshida H., & Smith, L. B. (2008). What’s in view for
toddlers? Using a head camera to study visual experience.
Infancy, 13(3), 229–248. doi: 10.1080/1525000080200
4437
Yurovsky, D., Fricker, D. C., Yu, C., & Smith, L. B. (2013).
The role of partial knowledge in statistical word learning.
Psychonomic Bulletin and Review. Advance online publi-
cation. doi: 10.3758/s13423-013-0443-y
Yurovsky, D., Smith, L. B., & Yu, C. (2013). Statistical word
learning at scale: The baby’s view is better. Developmental
Science, 16(6), 959–966. doi: 10.1111/desc.12036
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