The other-species effect in human perceptions of sexual dimorphism using human and macaque faces

Humans are better able to discriminate among human faces than faces of other species. This difference in perceptual discrimination is known as the “other-species effect”. Models of perception have posited that the ultimate functional significance of the other-species effect is a higher discrimination capability within an organism's most familiar and salient stimulus set while attenuating the ability to discriminate amongst unfamiliar stimuli. Here, human participants made masculinity judgements of human and macaque faces manipulated based on either human or macaque sexual dimorphism. Humans were more accurate at identifying masculine/feminine faces in species-congruent than species-incongruent transforms in both human and macaque faces. We observed an other-species effect whereby accuracy (correctly judging masculinized faces as more masculine) was highest for own-species faces. We also found that both men and women were better at judging the sex-typicality of male faces than female faces, regardless of the species of the face or the species of the manipulation. Our findings demonstrate an other-species effect for the perception of sex-typicality among human raters.     

Age biases in face processing: the effects of experience across development

In this paper, I review studies investigating discrimination and recognition abilities for faces of different ages in children and adults. Contrary to the earlier assertion that own-age faces are better recognized than other-age faces (own-age bias; OAB), I discuss recent evidence for a processing advantage for adult versus non-adult faces. This evidence is interpreted as suggesting that the precocious and continuous exposure to adult faces may shape the individual's face representation across development. Moreover, by testing how experience with faces of various ages acquired at different times in development modulates face-processing skills, this evidence shows that plasticity of face recognition abilities decreases with age, but early-acquired experience has enduring effects that impact our ability to learn from encounters with new types of faces in adulthood.     

知觉场理论对面孔知觉年龄偏差效应的解释

使用融合面孔范式和倒置面孔范式来研究面孔知觉的年龄偏差效应,检验知觉场能否作为面孔整体加工的指标,并以此发展年龄偏差的整体加工解释。结果发现：（1）成人和儿童在加工正立面孔时的知觉场均大于加工倒置面孔时的知觉场;（2）在加工正立面孔时,成人加工本年龄面孔比加工他年龄面孔的知觉场更大。上述结果表明：（1）知觉场大小可以作为面孔整体加工的指标,且受面孔朝向的影响;（2）知觉场假设可以解释面孔的年龄偏差效应。     

知觉场理论对面孔知觉年龄偏差效应的解释

使用融合面孔范式和倒置面孔范式来研究面孔知觉的年龄偏差效应,检验知觉场能否作为面孔整体加工的指标,并以此发展年龄偏差的整体加工解释。结果发现：（1）成人和儿童在加工正立面孔时的知觉场均大于加工倒置面孔时的知觉场;（2）在加工正立面孔时,成人加工本年龄面孔比加工他年龄面孔的知觉场更大。上述结果表明：（1）知觉场大小可以作为面孔整体加工的指标,且受面孔朝向的影响;（2）知觉场假设可以解释面孔的年龄偏差效应。     

Effects of Encoding Tasks on the Own-Age Face Recognition Bias

In the current study, we evaluated the own-age face recognition bias by using various encoding tasks to evaluate the robustness and potential limitations of the own-age bias. One hundred sixty young adults studied photographs of children, young adults, middle-aged adults, and older adults and were assigned to one of four encoding conditions (i.e., age estimate, attractiveness rating, friendliness rating, and a face search task). Subsequent recognition tests revealed a robust own-age bias such that participants recognized own-age faces better than other-age faces regardless of encoding task. The current study showed that encoding tasks that focus on socially relevant characteristics (i.e., attractiveness ratings and friendliness ratings) do not eliminate or weaken the own-age bias compared to tasks that specifically focus on the age of the face. These findings indicate that in-group/out-group categorization requires little conscious processing and may be automatic, which is consistent with Sporer's (2001) in-group/out-group model (IOM) of facial processing.     

Infants' discrimination of happy and sad music

Infants can detect information specifying affect in infant- and adult-directed speech, familiar and unfamiliar facial expressions, and in point-light displays of facial expressions. We examined 3-, 5-, 7-, and 9-month-olds' discrimination of musical excerpts judged by adults and preschoolers as happy and sad. In Experiment 1, using an infant-controlled habituation procedure, 3-, 5-, 7-, and 9-month-olds heard three musical excerpts that were rated as either happy or sad. Following habituation, infants were presented with two new musical excerpts from the other affect group. Nine-month-olds discriminated the musical excerpts rated as affectively different. Five- and seven-month-olds discriminated the happy and sad excerpts when they were habituated to sad excerpts but not when they were habituated to happy excerpts. Three-month-olds showed no evidence of discriminating the sad and happy excerpts. In Experiment 2, 5-, 7-, and 9-month-olds were presented with two new musical excerpts from the same affective group as the habituation excerpts. At no age did infants discriminate these novel, yet affectively similar, musical excerpts. In Experiment 3, we examined 5-, 7-, and 9-month-olds' discrimination of individual excerpts rated as affectively similar. Only the 9-month-olds discriminated the affectively similar individual excerpts. Results are discussed in terms of infants' ability to discriminate affect across a variety of events and its relevance for later social-communicative development.     

The own-age face recognition bias in children and adults

Children recognize children's faces more accurately than adult faces, and adults recognize adult faces more accurately than children's faces (e.g., Anastasi & Rhodes, 2005). This is the own-age bias. Research has shown that this bias is at least partially based on experience since trainee teachers show less of an own-age bias than do other adults (Harrison & Hole, 2009). The present research tested the own-age bias in three groups of children (age 4-6, 7-9, 10-12 years) and a group of adults in the recognition of three age groups of faces (age 7-9, 20-22, and 65-90 years). Results showed an own-age bias for 7- to 9-year-old children and adults. Specifically, children could recognize faces more accurately if they were less than two years different from their own age than if they were more than two years older or younger. These results are discussed in terms of short-term experience with faces creating biases, and this rapidly changes with age.     

Discriminating the sex of faces by 6- and 8-mo.-old infants

The goal of this study was to ascertain at what age infants could discriminate male and female faces using only the internal features of the face. The habituation-dishabituation technique was used to estimate infants' discrimination between male and female faces. Analysis showed that 8-mo.-old infants discriminated female and male faces, whereas 6-mo.-old infants did not, but showed an asymmetry in discrimination. 6-mo.-old infants who were habituated to the female face fixated consistently longer on the novel male face in test trials, so sex discrimination was complete but not observed after habituation to male faces. Data are discussed in relation to the role of experience in face discrimination.     

自闭症谱系障碍儿童对面孔加工的同龄偏向效应

采用视觉追踪技术,探讨自闭症谱系障碍(autism spectrum disorders, ASD)儿童面孔加工的同龄偏向效应。实验1选取19名ASD儿童和23名生理年龄匹配的普通儿童(typically developing, TD)为被试,通过自由观看同龄和异龄中性面孔,探讨ASD儿童是否存在面孔加工的同龄偏向效应;实验2选取22名ASD儿童和生理年龄匹配的25名TD儿童,通过自由观看快乐、愤怒和恐惧面孔,探讨情绪对ASD儿童面孔加工同龄偏向的影响。结果发现,(1)ASD儿童对同龄中性面孔的注视时间显著大于异龄中性面孔;(2)ASD儿童在愤怒和恐惧情绪下对同龄面孔的注视时间显著大于异龄面孔,而在快乐情绪下同龄和异龄的注视时间则无显著差异。这表明ASD儿童对面孔的注视加工存在同龄偏向效应,且受情绪的影响。     

Age differences in facial trustworthiness judgement based on multiple facial cues

Multiple facial cues such as facial expression and face gender simultaneously influence facial trustworthiness judgement in adults. The current work was to examine the effect of multiple facial cues on trustworthiness judgement across age groups. Eight-, 10-year-olds, and adults detect trustworthiness from happy and neutral adult faces (female and male faces) in Experiment 1. Experiment 2 included both adult and child faces wearing happy, angry, and neutral expressions. Nine-, 11-, 13-year-olds, and adults had to rate facial trustworthiness with a 7-point Likert scale. The results of Experiments 1 and 2 revealed that facial expression and face gender independently affected facial trustworthiness judgement in children aged 10 and below but simultaneously affected judgement in children aged 11 and above, adolescents, and adults. There was no own-age bias in children and adults. The results showed that children younger than 10 could not process multiple facial cues in the same manner as in older children and adults when judging trustworthiness. The current findings provide evidence for the stable-feature account, but not for the own-age bias account or the expertise account.     

The own-species face bias: A review of developmental and comparative data

Face recognition is characterized in part by biases resulting in enhanced perception and memory for individuals within frequently encountered groups and impaired recognition for individuals within uncommonly encountered groups. These biases are found across multiple categories and levels, including species, race, age, and gender (Scherf & Scott, 2012). At the highest level of categorization, human adults and nonhuman primates exhibit improved recognition (Dufour, Pascalis, & Petit, 2006; Pascalis & Bachevalier, 1998) and discrimination abilities (Pascalis, de Haan, & Nelson, 2002) for individuals within their own species, reflecting what has been called an “own-species” or “species-specific” bias in face processing. The own-species bias is a model system for delineating the role of experience and the developmental trajectory of face-processing biases, for further understanding the malleability of face biases in adults, and for examining and comparing face-processing abilities across species. Here, we will review findings from studies investigating the perception of other-species faces during development, into adulthood and across species.     

An own-age bias in face recognition for children and older adults

In the present study, we examined whether children and older adults exhibit an own-age face recognition bias. Participants studied photographs of children, younger adults, middle-aged adults, and older adults and were administered a recognition test. Results showed that both children and older adults more accurately recognized own-age faces than other-age faces. These data suggest that individuals may acquire expertise for identifying faces from their own age group and are discussed in terms of Sporer’s (2001) in-group/out-group model of face recognition.     

Perceptual specialization and configural face processing in infancy

Adults’ face processing expertise includes sensitivity to second-order configural information (spatial relations among features such as distance between eyes). Prior research indicates that infants process this information in female faces. In the current experiments, 9-month-olds discriminated spacing changes in upright human male and monkey faces but not in inverted faces. However, they failed to process matching changes in upright house stimuli. A similar pattern of performance was exhibited by 5-month-olds. Thus, 5- and 9-month-olds exhibited specialization by processing configural information in upright primate faces but not in houses or inverted faces. This finding suggests that, even early in life, infants treat faces in a special manner by responding to changes in configural information more readily in faces than in non-face stimuli. However, previously reported differences in infants’ processing of human versus monkey faces at 9 months of age (but not at younger ages), which have been associated with perceptual narrowing, were not evident in the current study. Thus, perceptual narrowing is not absolute in the sense of loss of the ability to process information from other species’ faces at older ages.     

Development of body emotion perception in infancy: From discrimination to recognition

Research suggests that infants progress from discrimination to recognition of emotions in faces during the first half year of life. It is unknown whether the perception of emotions from bodies develops in a similar manner. In the current study, when presented with happy and angry body videos and voices, 5-month-olds looked longer at the matching video when they were presented upright but not when they were inverted. In contrast, 3.5-month-olds failed to match even with upright videos. Thus, 5-month-olds but not 3.5-month-olds exhibited evidence of recognition of emotions from bodies by demonstrating intermodal matching. In a subsequent experiment, younger infants did discriminate between body emotion videos but failed to exhibit an inversion effect, suggesting that discrimination may be based on low-level stimulus features. These results document a developmental change from discrimination based on non-emotional information at 3.5 months to recognition of body emotions at 5 months. This pattern of development is similar to face emotion knowledge development and suggests that both the face and body emotion perception systems develop rapidly during the first half year of life.     

Differential attentional allocation and subsequent recognition for young and older adult faces

Studies examining own-age recognition biases report inconsistent results and often utilize paradigms that present faces individually and in isolation. We investigated young and older adults' attention towards young and older faces during learning and whether differential attention influences recognition. Participants viewed complex scenes while their eye movements were recorded; each scene contained two young and two older faces. Half of the participants formed scene impressions and half prepared for a memory test. Participants then completed an old/new face recognition task. Both age groups looked longer at young than older faces; however, only young adults showed an own-age recognition advantage. Participants in the memory condition looked longer at faces but did not show enhanced recognition relative to the impressions condition. Overall, attention during learning did not influence recognition. Our results provide evidence for a young adult face bias in attentional allocation but suggest that longer looking does not necessarily indicate deeper encoding.     

Stable middle-aged face recognition: No moderation of the own-age bias across contexts

The own-age bias (OAB) has been proposed to be caused by perceptual expertise and/or social-cognitive mechanisms. Investigations into the role of social cognition have, however, yielded mixed results. One reason for this might be the tendency for research to focus on the OAB in young adults, between young and older adult faces where other-age individuation experience is low. To explore whether social-cognitive manipulations may be successful when observers have sufficient other-age individuation experience, we examined biases involving middle-aged other-age faces and the influence of a context manipulation. Across four experiments, young adult participants were presented with middle-aged faces alongside young or older adult faces to remember. We predicted that in contexts where middle-aged faces were positioned as other-age faces (alongside young adult faces), recognition performance would be worse than when they were positioned as relative own-age faces (alongside older adult faces). However, the context manipulations did not moderate middle age face recognition. This suggests that past findings that context does not change other-age face recognition holds for other-age faces for which observers have higher individuation experience. These findings are consistent with a perceptual expertise account of the OAB but more investigation of the generality of these results is required.     

Ageing faces in ageing minds: A review on the own-age bias in face recognition

Similar to the well-established own-race bias, participants are more accurate at remembering own- relative to other-age faces. An own-age bias (OAB) in face memory was demonstrated in participants older than approximately 5 years. Crucially, the OAB is modulated by contact—participants with substantial contact with other-age persons show either reduced or absent OAB effects. In line with a perceptual expertise account of the phenomenon, holistic processing of other-age faces is less efficient when tested with young adult versus child faces, and differential holistic processing may therefore reflect one mechanism contributing to the OAB. A possible additional contribution of sociocognitive factors to the OAB remains largely untested. Importantly, event-related brain potential studies suggest that the own-race and own-age biases are based on at least partly different mechanisms. Theoretical explanations for different group-based biases in face memory will need to consider these findings.     

Building biases in infancy: the influence of race on face and voice emotion matching

Early in the first year of life infants exhibit equivalent performance distinguishing among people within their own race and within other races. However, with development and experience, their face recognition skills become tuned to groups of people they interact with the most. This developmental tuning is hypothesized to be the origin of adult face processing biases including the other-race bias. In adults the other-race bias has also been associated with impairments in facial emotion processing for other-race faces. The present investigation aimed to show perceptual narrowing for other-race faces during infancy and to determine whether the race of a face influences infants' ability to match emotional sounds with emotional facial expressions. Behavioral (visual-paired comparison; VPC) and electrophysiological (event-related potentials; ERPs) measures were recorded in 5-month-old and 9-month-old infants. Behaviorally, 5-month-olds distinguished faces within their own race and within another race, whereas 9-month-olds only distinguish faces within their own race. ERPs were recorded while an emotion sound (laughing or crying) was presented prior to viewing an image of a static African American or Caucasian face expressing either a happy or a sad emotion. Consistent with behavioral findings, ERPs revealed race-specific perceptual processing of faces and emotion/sound face congruency at 9 months but not 5 months of age. In addition, from 5 to 9 months, the neural networks activated for sound/face congruency were found to shift from an anterior ERP component (Nc) related to attention to posterior ERP components (N290, P400) related to perception.     

Children view own-age faces qualitatively differently to other-age faces

Like most own-group biases in face recognition, the own-age bias (OAB) is thought to be based either on perceptual expertise or socio-cognitive motivational mechanisms [Wolff, N., Kemter, K., Schweinberger, S. R., &; Wiese, H. (2013). What drives social in-group biases in face recognition memory? ERP evidence from the own-gender bias. Social Cognitive and Affective Neuroscience. doi:10.1093/scan/nst024]. The present study employed a recognition paradigm with eye-tracking in order to assess whether participants actively viewed faces of their own-age differently to that of other-age faces. The results indicated a significant OAB (superior recognition for own-age relative to other-age faces), provided that they were upright, indicative of expertise being employed for the recognition of own-age faces. However, the eye-tracking results indicate that viewing other-age faces was qualitatively different to the viewing of own-age faces, with more nose fixations for other-age faces. These results are interpreted as supporting the socio-cognitive model of the OAB.     

An own-age bias in age estimation of faces

IntroductionAge estimation performances may be influenced by group biases.ObjectiveThis study investigated whether we are more accurate at estimating the age of people from one's own-age than the age of younger or older people.MethodChildren, young and older adults’ performances at estimating both in-group and out-group faces were compared.ResultsA significant “Age of participants” × “Age of face stimuli” interaction was revealed. Moreover, the age of children's faces was more accurately estimated than the age of young and older adults’ faces by the three groups of participants.ConclusionThe present results revealed the occurrence of an own-age bias for children, young and older adults in age estimation. Several explanations to this own-age effect are discussed.