Shape, color and the other‐race effect in the infant brain

Abstract

The “other-race” effect describes the phenomenon in which faces are difficult to distinguish from one another if they belong to an ethnic or racial group to which the observer has had little exposure. Adult observers typically display multiple forms of recognition error for other-race faces, and infants exhibit behavioral evidence of a developing other-race effect at about 9 months of age. The neural correlates of the adult other-race effect have been identified using ERPs and fMRI, but the effects of racial category on infants’ neural response to face stimuli have to date not been described. We examine two distinct components of the infant ERP response to human faces and demonstrate through the use of computer-generated “hybrid” faces that the observed other-race effect is not the result of low-level sensitivity to 3D shape and color differences between the stimuli. Rather, differential processing depends critically on the joint encoding of race-specific features.

Neural correlates of own- and other-race face recognition in children: A functional near-infrared spectroscopy study

“…This finding suggests that neural responses might be more sensitive to the processing differences between own- and other-race faces, consistent with the finding by Balas et al (2011) with infants. The existing adult fMRI studies found that face-race related differential activation in the IFG and MFG is involved in the processing of higher level categorical information associated with the faces as well as familiarity (personal information) (e.g.…”

“…Except for one ERP study demonstrating infants to respond differentially to own- and other-race faces (Balas, Westerlund, Hung, & Nelson, 2011), to the best of our knowledge, no neuroimaging study to date has investigated the neural correlates of own- and other-race face processing in children. Neuroimaging research on the development of the other-race effect will bridge the significant gap in our knowledge about how the neural other-race effect emerges and develops in childhood.…”

Children’s neural response to contrast-negated faces is species specific

“…This is evident for categories defined by race (Kelly et al, 2007) and species (Pascalis et al, 2005) and is taken to imply that the representation of face appearance has “narrowed” or converged to a state that is optimal for the subset of faces that infants see most frequently, but potentially sub-optimal for other types of faces. The effects of perceptual narrowing are evident both behaviorally and in electrophysiological data – ERP components including the N290 and the P400 are sensitive to face category membership in a manner that is broadly consistent with perceptual narrowing (de Haan, Pascalis & Johnson, 2002; Balas et al, 2011), which suggests that neural representations of face appearance are being substantially modulated by experience during the first year of life.…”

Children (but not adults) judge similarity in own- and other-race faces by the color of their skin

“…The deleterious effects of contrast negation on face recognition appear to be driven in large part by disruption of natural pigmentation (Vuong et al, 2005) suggesting that observers cannot ignore pigmentation information in face images. Observers appear to use both face shape and pigmentation to categorize faces according to race (Hill, Bruce, & Akamatsu, 1995) and shape and pigmentation make separate contributions to the behavioral other-race effect (Bar-Haim, Seidel, & Yovel, 2009) and its neural basis (Balas & Nelson, 2010; Balas et al, 2012). The dependence of the other-race effect on shape (Brooks and Gwinn, 2010) vs. pigmentation (Willenbockel, Fiset, & Tanaka 2011; Sun & Balas, 2012) remains to some extent unclear, but it is clear that shape and pigmentation are perceptually meaningful properties of facial appearance that impact how own- and other-race faces are processed.…”

“…The other-race effect also appears to be plastic at this point in childhood (Sangrigoli et al, 2005; Bar-Haim et al, 2006) suggesting that children of this age may still be “tuning” or “narrowing” their perception of faces considerably based on their experience with faces in the environment. Indeed, previous results with infants (9 months of age) and adults demonstrate that sensitivity to race-specific shape and pigmentation changes substantially between late infancy and adulthood (Balas et al, 2011; Balas & Nelson, 2010), making early childhood a critically important target for examining the impact of differential experience. Finally, children in this age range can reliably complete a match-to-sample paradigm that is meaningful to administer to adults, facilitating comparison between the two groups.…”