The Other‐Race Effect in Infancy: Evidence Using a Morphing Technique

Human adults are more accurate at discriminating faces from their own race than faces from another race. This other‐race effect (ORE) has been characterized as a reflection of face processing specialization arising from differential experience with own‐race faces. We examined whether 3.5‐month‐old infants exhibit ORE using morphed faces on which adults had displayed a crossover ORE (i.e., Caucasians performed better on Caucasian faces and Asians performed better on Asian faces). In this experiment, Caucasian infants who had grown up in a predominantly Caucasian environment discriminated 100% Caucasian faces from 70% Caucasian/30% Asian morphed faces but failed to discriminate between the corresponding 100% Asian and 70% Asian/30% Caucasian faces. Thus, 3.5‐month‐olds exhibited evidence of ORE. These results indicate that at least by 3.5 months of age, infants have attained enough face processing expertise to process familiar‐race faces in a different manner than unfamiliar‐race faces.     

The Development of Specialized Processing of Own‐Race Faces in Infancy

In this study, we examined developmental changes in infants' processing of own‐ versus other‐race faces. Caucasian American 8‐month‐olds (Experiment 1) and 4‐month‐olds (Experiment 2) were tested in a habituation‐switch procedure designed to assess holistic (attending to the relationship between internal and external features of the face) versus featural (attending to individual features of the face) processing of faces. Eight‐month‐olds demonstrated holistic processing of upright own‐race (Caucasian) faces, but featural processing of upright other‐race (African) faces. Inverted faces were processed featurally, regardless of ethnicity. Four‐month‐olds, however, demonstrated holistic processing of both Caucasian and African upright faces. These results demonstrate that infants' processing of own‐ versus other‐race faces becomes specialized between 4 and 8 months.     

Cross‐Race Preferences for Same‐Race Faces Extend Beyond the African Versus Caucasian Contrast in 3‐Month‐Old Infants

A visual preference procedure was used to examine preferences among faces of different ethnicities (African, Asian, Caucasian, and Middle Eastern) in Chinese 3‐month‐old infants exposed only to Chinese faces. The infants demonstrated a preference for faces from their own ethnic group. Alongside previous results showing that Caucasian infants exposed only to Caucasian faces prefer same‐race faces (Kelly et al., 2005) and that Caucasian and African infants exposed only to native faces prefer the same over the other‐race faces (Bar‐Haim, Ziv, Lamy, & Hodes, 2006), the findings reported here (a) extend the same‐race preference observed in young infants to a new race of infants (Chinese), and (b) show that cross‐race preferences for same‐race faces extend beyond the perceptually robust contrast between African and Caucasian faces.     

Follow My Gaze: Face Race and Sex Influence Gaze‐Cued Attention in Infancy

Using the eye gaze of others to direct one's own attention develops during the first year of life and is thought to be an important skill for learning and social communication. However, it is currently unclear whether infants differentially attend to and encode objects cued by the eye gaze of individuals within familiar groups (e.g., own race, more familiar sex) relative to unfamiliar groups (e.g., other race, less familiar sex). During gaze cueing, but prior to the presentation of objects, 10‐month‐olds looked longer to the eyes of own‐race faces relative to 5‐month‐olds and relative to the eyes of other‐race faces. After gaze cueing, two objects were presented alongside the face and at both ages, infants looked longer to the uncued objects for faces from the more familiar‐sex and longer to cued objects for the less familiar‐sex faces. Finally, during the test phase, both 5‐ and 10‐month‐old infants looked longer to uncued objects relative to cued objects but only when the objects were cued by an own‐race and familiar‐sex individual. Results demonstrate that infants use face eye gaze differently when the cue comes from someone within a highly experienced group.     

The Other‐Race Effect in a Longitudinal Sample of 3‐, 6‐ and 9‐Month‐Old Infants: Evidence of a Training Effect

We investigated the development of the other‐race effect “ORE” in a longitudinal sample of 3‐, 6‐, and 9‐month‐old Caucasian infants. Previous research using cross‐sectional samples has shown an unstable ORE at 3 months, an increase at 6 months and full development at 9 months. In Experiment 1, we tested whether 9‐month‐olds showed the ORE with Caucasian and African faces. As expected, the 9‐month‐olds discriminated faces within their own ethnicity (Caucasian) but not within the unfamiliar ethnicity (African). In months. In Experiment 2, we longitudinally tested infants at 3, 6, and 9 months by presenting either the Caucasian or the African faces used in Experiment 1. In contrast to previous cross‐sectional studies and Experiment 1, we found that infants discriminated between all stimuli. Hence, we did not find the ORE in this longitudinal study even at 9 months. We assume that the infants in our longitudinal study showed no ORE because of previous repetitive exposure to African faces at 3 and 6 months. We argue that only a few presentations of faces from other ethnic categories sufficiently slow the development of the ORE.     

Neural Correlates of Human and Monkey Face Processing in 9‐Month‐Old Infants

Behavioral and electrophysiological evidence suggests a gradual, experience‐dependent specialization of cortical face processing systems that takes place largely in the 1st year of life. To further investigate these findings, event‐related potentials (ERPs) were collected from typically developing 9‐month‐old infants presented with pictures of familiar and unfamiliar monkey or human faces in 2 different orientations. Analyses revealed differential processing across changes in monkey and human faces. The N290 was greater for familiar compared to unfamiliar faces, regardless of species or orientation. In contrast, the P400 to unfamiliar faces was greater than to familiar faces, but only for the monkey condition. The P400 to human faces differentiated the orientation of both familiar and unfamiliar faces. These results suggest more specific processing of human compared to monkey faces in 9‐month‐olds.     

Integrated Emotion Processing in Infancy: Matching of Faces and Bodies

Accurate assessment of emotion requires the coordination of information from different sources such as faces, bodies, and voices. Adults readily integrate facial and bodily emotions. However, not much is known about the developmental origin of this capacity. Using a familiarization paired‐comparison procedure, 6.5‐month‐olds in the current experiments were familiarized to happy, angry, or sad emotions in faces or bodies and tested with the opposite image type portraying the familiar emotion paired with a novel emotion. Infants looked longer at the familiar emotion across faces and bodies (except when familiarized to angry images and tested on the happy/angry contrast). This matching occurred not only for emotions from different affective categories (happy, angry) but also within the negative affective category (angry, sad). Thus, 6.5‐month‐olds, like adults, integrate emotions from bodies and faces in a fairly sophisticated manner, suggesting rapid development of emotion processing early in life.     

9‐Month‐Old Infants Recognize Individual Unfamiliar Faces in a Rapid Repetition ERP Paradigm

To investigate whether infants show neural signatures of recognizing unfamiliar human faces, we tested 9‐month‐olds (N = 31) in a rapid repetition ERP paradigm. Pictures of unfamiliar male and female faces (targets) were preceded either by a central attractor (Unprimed) or by a face (Primed). In the latter case, the prime faces were either identical to the target (Repeated) or not (Unrepeated). We compared processing of primed versus unprimed faces as well as processing of repeated versus unrepeated faces. Primed stimuli elicited decreased P1 amplitude, P1 latency and N290 amplitude, indicating categorical repetition effects very early during the stream of processing. For repeated relative to unrepeated faces, N290 latency was reduced. In addition, we observed an enhanced late positivity at occipital channels for unrepeated compared to repeated male faces, but no difference for female faces. Taken together, these results suggest that 9‐month‐olds categorize faces before discriminating them individually. Furthermore, infants' ability to recognize face identity seems to depend on familiarity with the given face category, as indicated by differences in brain responses to male and female faces.     

Speed of Processing and Face Recognition at 7 and 12 Months

This research examined developmental and individual differences in infants' speed of processing faces and the relation of processing speed to the type of information encoded. To gauge processing speed, 7‐ and 12‐month‐olds were repeatedly presented with the same face (frontal view), each time paired with a new one, until they showed a consistent preference for the new one. Subsequent probe trials assessed recognition of targets that either preserved configural integrity (Study 1: 3/4 profile and full profile poses) or disrupted it while preserving featural information (Study 2: rotations of 160° or 200° and fracturings). There were developmental differences in both speed and in infants' appreciation of information about faces. Older infants took about 60% fewer trials to reach criterion and had more mature patterns of attention (i.e., looks of shorter duration and more shifts of gaze). Whereas infants of both ages recognized the familiar face in a 3/4 pose, the 12‐month‐olds also recognized it in profile and when rotated. Twelve‐month‐olds who were fast processors additionally recognized the fractured faces; otherwise, processing speed was unrelated to the type of information extracted. At 7 months then, infants made use of some configural information in processing faces; at 12 months, they made use of even more of the configural information, along with part‐based or featural information.     

Young Infants Match Facial and Vocal Emotional Expressions of Other Infants

Research has demonstrated that infants recognize emotional expressions of adults in the first half year of life. We extended this research to a new domain, infant perception of the expressions of other infants. In an intermodal matching procedure, 3.5‐ and 5‐month‐old infants heard a series of infant vocal expressions (positive and negative affect) along with side‐by‐side dynamic videos in which one infant conveyed positive facial affect and another infant conveyed negative facial affect. Results demonstrated that 5‐month‐olds matched the vocal expressions with the affectively congruent facial expressions, whereas 3.5‐month‐olds showed no evidence of matching. These findings indicate that by 5 months of age, infants detect, discriminate, and match the facial and vocal affective displays of other infants. Further, because the facial and vocal expressions were portrayed by different infants and shared no face–voice synchrony, temporal, or intensity patterning, matching was likely based on detection of a more general affective valence common to the face and voice.     

Infants Experience Perceptual Narrowing for Nonprimate Faces

Perceptual narrowing—a phenomenon in which perception is broad from birth, but narrows as a function of experience—has previously been tested with primate faces. In the first 6 months of life, infants can discriminate among individual human and monkey faces. Though the ability to discriminate monkey faces is lost after about 9 months, infants retain human face discrimination, presumably because of their experience with human faces. The current study demonstrates that 4‐ to 6‐month‐old infants are able to discriminate nonprimate faces as well. In a visual paired comparison test, 4‐ to 6‐month‐old infants (n = 26) looked significantly longer at novel sheep (Ovis aries) faces, compared to a familiar sheep face (p = .017), while 9‐ to 11‐month‐olds (n = 26) showed no visual preference, and adults (n = 27) had a familiarity preference (p < .001). Infants’ face recognition systems are broadly tuned at birth—not just for primate faces, but for nonprimate faces as well—allowing infants to become specialists in recognizing the types of faces encountered in their first year of life.     

Long‐Term Memory for an Emotional Interpersonal Interaction Occurring at 5 Months of Age

We examined infants' long‐term retention of a single unique emotional experience into early childhood. Twenty‐month‐olds who had participated in a still‐face procedure at 5 months (experience group) fixated the face of the person who had instigated the still face significantly less than the faces of 2 other novel persons. Control 20‐month‐olds (no‐experience group) looked longer overall and fixated the target person equally or more than the 2 novel persons. In short, children who interacted with a stranger in the laboratory under both natural and anomalous social conditions just once when they were infants apparently retained a specific memory of that person and the experience into toddlerhood.     

Emergence of a consonant bias during the first year of life: New evidence from own‐name recognition

Recent evidence suggests that during the first year of life, a preference for consonant information during lexical processing (consonant bias) emerges, at least for some languages like French. Our study investigated the factors involved in this emergence as well as the developmental consequences for variation in consonant bias emergence. In a series of experiments, we measured 5‐, 8‐, and 11‐month‐old French‐learning infants orientation times to a consonant or vowel mispronunciation of their own name, which is one of the few word forms familiar to infants at this young age. Both 5‐ and 8‐month‐olds oriented longer to vowel mispronunciations, but 11‐month‐olds showed a different pattern, initially orienting longer to consonant mispronunciations. We interpret these results as further evidence of an initial vowel bias, with consonant bias emergence by 11 months. Neither acoustic‐phonetic nor lexical factors predicted preferences in 8‐ and 11‐month‐olds. Finally, counter to our predictions, a vowel bias at the time of test for 11‐month‐olds was related to later productive vocabulary outcomes.     

Attention during Visual Preference Tasks: Relation to Caregiving and Face Recognition

This research examined how caregiver experience (female primary caregiver or distributed caregiving with mom and dad) influenced 10‐, 14‐, and 16‐month‐olds’ visual preferences and attention toward internal facial features of female–male face pairs, and how these behaviors related to novelty preferences in a face recognition task and speed and accuracy on a visual search task. In the visual preference task, infants visually preferred male faces, regardless of caregiver experience. Despite similarities in visual preferences, infants’ attention toward females and males’ internal facial features was related for infants with distributed caregiving only. Infants’ performance across face processing tasks most often correlated for those with female primary caregivers. Results further our understanding of how infants with female primary caregivers display specialized processing of female faces, and how infants with distributed caregiving show similarities in their attention to female and male facial features.     

Evidence of the Face Inversion Effect in 4‐Month‐Old Infants

This study tested the presence of the face inversion effect in 4‐month‐old infants using habituation to criterion followed by a novelty preference paradigm. Results of Experiment 1 confirmed previous findings, showing that when 1 single photograph of a face is presented in the habituation phase and when infants are required to recognize the same photograph, no differences in recognition performance with upright and inverted faces are found. However, Experiment 2 showed that, when infants are habituated to a face shown in a variety of poses and are required to recognize a new pose of the same face, infants' recognition performances were higher for upright than for inverted faces. Overall, results indicate that, under some experimental conditions, 4‐month‐olds process faces differently according to whether faces are presented upright or inverted.     

Infants Discriminate the Affective Expressions of their Peers: The Roles of Age and Familiarization Time

Research examining infants’ discrimination of affect often uses unfamiliar faces and voices of adults. Recently, research has examined infant discrimination of affect in familiar faces and voices. In much of this research, infants were habituated to the affective expressions using a “standard” 50% habituation criterion. We extend this line of research by examining infants’ discrimination of unfamiliar peers’, that is, 4‐month‐olds, dynamic, facial, and vocal affective expressions and assessing how discrimination is affected by changing the habituation criterion. In two experiments, using an infant‐controlled habituation design, we explored 3‐ and 5‐month‐olds’ discrimination of their peers’ dynamic audiovisual displays of positive and negative expressions of affect. Results of Experiment 1, using a 50% habituation criterion, revealed that 5‐month‐olds, but not 3‐month‐olds discriminated the affective expressions of their peers. In Experiment 2, we examined whether 3‐month‐olds’ lack of discrimination in Experiment 1 was a result of insufficient habituation (i.e., familiarization). Specifically, 3‐month‐olds were habituated using a 70% habituation criterion, providing them with longer familiarization time. Results revealed that using the more stringent habituation criterion, 3‐month‐olds showed longer habituation times, that is increased familiarization, and discriminated their peers’ affective expressions. Results are discussed in terms of infants’ discrimination of affect, the role of familiarization time, and limitations of the 50% habituation criterion.     

Greater Pupil Size in Response to Emotional Faces as an Early Marker of Social‐Communicative Difficulties in Infants at High Risk for Autism

When scanning faces, individuals with autism spectrum disorder (ASD) have shown reduced visual attention (e.g., less time on eyes) and atypical autonomic responses (e.g., heightened arousal). To understand how these differences might explain subclinical variability in social functioning, 9‐month‐olds, with or without a family history of ASD, viewed emotionally expressive faces, and gaze and pupil diameter (a measure of autonomic activation) were recorded using eye‐tracking. Infants at high risk for ASD with no subsequent clinical diagnosis (HRA‐) and low‐risk controls (LRC) showed similar face scanning and attention to eyes and mouth; attention was overall greater to eyes than mouth, but this varied as a function of the emotion presented. As a group, HRA‐ showed significantly larger pupil size than LRC. Correlations between scanning at 9 months, pupil size at 9 months, and 18‐month social‐communicative behavior, revealed positive associations between pupil size and attention to both face and eyes at 9 months in LRC, and a negative association between 9‐month pupil size and 18‐month social‐communicative behavior in HRA‐.The present findings point to heightened autonomic arousal in HRA‐. Further, with greater arousal relating to worse social‐communicative functioning at 18 months, this work points to a mechanism by which unaffected siblings might develop atypical social behavior.     

Relationship Between Maternal Sensitivity During Early Interaction and Maternal Ability in Perceiving Infants' Body and Face

Maternal sensitivity has been considered an indicator of mother‐infant quality interaction, however little is known about the perception processes associated to this parental behavior style. Here we aimed to explore the relationship between maternal sensitivity during a face‐to‐face interaction with their infants and maternal ability in perceiving infants' body and face. Thirty‐six 6 month‐old infants and their mothers were videotaped during a mother‐infant interaction to identify those with high and low sensitivity. Then, mothers were tested using an inversion effect paradigm requiring the visual discrimination of upright and inverted pictures of whole bodies and faces of their own and unfamiliar infants; this allowed estimation of their configural perceptual processing abilities. Results showed that high‐sensitivity mothers showed reduced body configural processing for others' infants as compared to configural processing of their own infant, whereas low‐sensitivity mothers were engaged in comparable body configural processing independently from infant identity. Infants' face configural processing did not distinguish between high‐ and low‐sensitivity mothers. Our findings suggest that high‐sensitivity mothers have refined their use of configural processing of body postures to be selective for their own infants, suggesting that this visuo‐perceptual strategy makes much more efficient the mothers' ability in detecting, discriminating and recognizing own infant's cues.     

Relations Between Mother‐Child Interactions and the Neural Correlates of Face Processing in 6‐Month‐Olds

Developmental studies of face processing have revealed age‐related changes in how infants allocate neurophysiological resources to the face of a caregiver and an unfamiliar adult. We hypothesize that developmental changes in how infants interact with their caregiver are related to the changes in brain response. We studied 6‐month‐olds because this age is frequently noted in the behavioral and neurophysiological literature as a time of transition in which infants begin to discriminate more readily between caregivers and unfamiliar adults. We used infants' behavioral responses to an original behavioral paradigm to predict event‐related potential (ERP) responses to pictures of the mother's face and a stranger's face in the same group of participants. Our results suggest that individual differences in infants' proximity‐seeking behaviors during interactions with the mother correlate with their neurophysiological responses to the mother's face as opposed to an unfamiliar face for the Nc component of the ERP. These results have implications for understanding the role of the changing infant‐caregiver relationship on the development of the face processing system in early infancy.     

Getting into the Groove: The Development of Tempo‐Flexibility Between 10 and 18 Months of Age

Despite good early rhythm processing abilities, and clear enjoyment of music, infants appear not to be able to spontaneously synchronize their movement to the beat of a song (Zentner and Eerola, Proceedings of the National Academy of Sciences, 107, 2010, 5768). We present a new social bell‐ringing task designed to facilitate synchronous movement to music in infants. Ten‐month‐olds, 18‐month‐olds, and adults were played musical tracks of various tempos and given handheld bells to ring, in the presence of either a live experimenter or an animated nonsocial stimulus. Surface electromyography (EMG) was used to measure the timing of arm movements during periods of bell ringing. Infants showed no evidence of synchronous bell ringing at any tempo. However, while the 10‐month‐olds did not modulate their ringing to the music tempo, the 18‐month‐olds showed tempo‐flexibility. Moreover, 18‐month‐olds displayed more associated behaviors such as bouncing and rocking in the absence (rather than presence) of a social partner, whereas the behavior of the 10‐month‐olds was not modulated by the presence or absence of a social partner. The results suggest a distinction between “moving together” and “moving to the beat,” which may have separate underlying mechanisms and developmental trajectories.