Neural correlates of individuation and categorization of other-species faces in infancy

Abstract

The goal of this study was to investigate 9-month-old infants' ability to individuate and categorize other-species faces at the subordinate level. We were also interested in examining the effects of initial exposure conditions on infant categorization and individuation processes. Infants were either familiarized with a single monkey face in an individuation procedure or familiarized with multiple exemplars of monkey faces from the same species in a categorization procedure. Event-related potentials were recorded while the infants were presented: familiar faces, novel faces from the familiar species, or novel faces from a novel species. The categorization group categorized monkey faces by species at the subordinate level, whereas the individuation group did not discriminate monkey faces at the individual or subordinate level. These findings indicate initial exposure to multiple exemplars facilitates infant processing of other-species faces, and infants are efficient at subordinate-level categorization at 9 months of age.

The Development of Attentional Biases for Faces in Infancy: A Developmental Systems Perspective

“…Research from our lab ( Dixon et al, 2017 ), has shown that although infants demonstrate poor performance at individuating monkey faces based on perceptual narrowing, they do seem to be efficient at categorizing other-species faces at 9 months of age. In addition to analyzing face processing components, we analyzed the Negative central (Nc) ERP component associated with infant attentional engagement ( Courchesne et al, 1981 ; de Haan and Nelson, 1997 , 1999 , Reynolds and Richards, 2005 ; Reynolds et al, 2010 ; Reynolds, 2015 ; Reynolds and Romano, 2016 ).…”

“…The shaded rectangle indicates the time window for the analysis of Nc. Time following stimulus onset is shown on the X -axis, and change in amplitude of the ERP (in microvolts) is shown on the Y -axis (Figure adapted from Dixon et al, 2017 ).…”

The Biological Basis of Social Cognition During Development

“…However, the effects of certain stimulus manipulations (emotions and spatial frequency) were not stable across measurement time points, calling into question whether differential responses can reliably be seen as indicative of individual developmental trajectories. Dixon et al (2017) focus on the effects of exposure to other-species faces on categorization and individuation in 9-month-olds' ERP responses. Whereas exposure to multiple exemplars facilitated infant categorization of monkey faces on the subordinate level, familiarization to an individual monkey face did not affect infant categorization or individuation of monkey faces, speaking to the specific effects of exposure to multiple exemplars of an unfamiliar face category on infant face perception.…”