The left perceptual bias for adult and infant faces in adults and 5-year-old children: Face age matters

Abstract

A large number of studies have shown that adults rely more heavily on information conveyed by the left side of the face in judging emotional state, gender and identity. This phenomenon, called left perceptual bias (LPB), suggests a right hemisphere lateralization of face processing mechanisms. Although specialization of neural mechanisms for processing over-experienced face categories begins during the first year of life, little is known about the developmental trajectory of the LPB and whether or when the bias becomes selective for specific face categories as a result of experience. To address these questions we tested adults (Experiment 1) and 5-year-old children (Experiment 2) with null or limited experience with infants in an identity matching-to-sample task with chimeric adult and infant faces, for which both adults and children have been shown to manifest differential processing abilities. Results showed that 5-year-olds manifest a leftward bias selective for adult faces, and the magnitude of the bias is larger for adult compared to infant faces in adults. This evidence is in line with earlier demonstrations of a perceptual processing advantage for adult faces in adults and children and points to the role of experience in shaping neurocognitive specialization for face processing.

The Presentation Location of the Reference Stimuli Affects the Left-Side Bias in the Processing of Faces and Chinese Characters

“…Chimeric stimuli created from the left side of an overlearned stimulus are judged as being more similar to the original stimuli (e.g., Brady et al, 2005 ; Coolican, et al, 2008 ; Hsiao and Cottrell, 2009 ; Chung et al, 2017 ). Previous studies have demonstrated that this bias is consistently observed in face and Chinese character processing (e.g., Luh et al, 1991 ; Burt and Perrett, 1997 ; Hsiao and Cottrell, 2009 ; Balas and Moulson, 2011 ; Megreya and Havard, 2011 ; Tso et al, 2014 ; Proietti et al, 2015 ; Chung et al, 2017 ). The results of the present experiments confirm the left-side bias in face and Chinese character processing in Chinese adults.…”

“…In a facial expression judgment task, Wolff ( 1933 ) first observed the left-side bias effect. This effect was later replicated by Gilbert and Bakan ( 1973 ) in a face perception judgment task, and it has been found in tasks involving the processing of other aspects of faces, such as facial identity (e.g., Coolican, et al, 2008 ; Proietti et al, 2015 ), emotion (e.g., David, 1993 ; Ferber and Murray, 2005 ; Bourne, 2008 , 2011 ; Coolican, et al, 2008 ), gender (e.g., Luh et al, 1991 ; Butler and Harvey, 2005 , 2008 ), age and attractiveness (e.g., Burt and Perrett, 1997 ), and aesthetic preferences (e.g., Heath et al, 2005 ). Consistent with these findings, eye-tracking studies have found a preference for the left side of faces during the visual exploration of faces.…”

“…Regarding the left-side bias effect in face processing, when the face was presented in the left visual field, it may be directly reflected in the right hemisphere (in the FFA), causing a significant left-side bias effect. Many previous studies have attributed the left-side bias effect in face processing to the right hemisphere dominance for face recognition (e.g., Gilbert and Bakan, 1973 ; Rhodes, 1985 ; Brady et al, 2005 ; Yovel et al, 2008 ; Proietti et al, 2015 ). In the meantime, the left-to-right reading habit may also affect the left-side bias in face processing.…”

“…Adults are experts at recognizing human faces and words. Many behavioral effects have been used to investigate the mechanism of the perceptual expertise, for instance, the inversion effect (e.g., Yin, 1969 ; Haxby et al, 1999 ), the composite effect (for a review, see Richler and Gauthier, 2014 ), and the left-side bias (e.g., Gilbert and Bakan, 1973 ; Hsiao and Cottrell, 2009 ; Proietti et al, 2015 ). The left-side bias refers to the process by which a chimeric face created from the left side of a face (from the viewer's perspective) and its mirror image are considered more similar to the original/reference face than a chimeric face created from the right side of the same face and its mirror image.…”

Relationship status and sex differences in emotion lateralisation: An examination contrasting the processing of emotional infant and adult faces

“…They found a significant left hemiface (right hemisphere) bias for the infant stimuli, particularly for faces with a negative emotional expression. More recently, Proietti, Pavone, Ricciardelli, and Cassia (2015) formed chimeric faces from infants aged 3-4 days old with a neutral expression, and used these in a paradigm where individual unmanipulated target faces had to be matched for identity to one of two probe chimeric faces. In adult participants, they found a significant left visual field (right hemisphere) bias for both adult and infant faces, although the bias was significantly stronger for adult faces than for infant faces.…”