Newly learned categories induce pre-attentive categorical perception of faces

Mengxia Yu,Ce Mo,Lei Mo,You Li

doi:10.1038/s41598-017-14104-6

Abstract

Face perception is modulated by categorical information in faces, which is known as categorical perception (CP) of faces. However, it remains unknown whether CP of faces is humans’ inborn capability or the result of acquired categories. Here, we examined whether and when newly learned categories affect face perception. A short-term training method was employed in which participants learned new categories of face stimuli. Behaviorally, using an AB-X discrimination task, we found that the discrimination accuracy of face pairs from different learned categories was significantly higher than that of faces from the same category. Neurally, using a visual oddball task, we found that deviant stimuli whose category differed from standard stimuli evoked a larger N170. Importantly, the visual mismatch negativity (vMMN), starting from 140 ms after stimuli onset, was stronger with the between-category deviants than with the within-category deviants under the unattended condition. Altogether, our study provides empirical evidence indicating that CP of faces could be induced by newly learned categories, and this effect occurs automatically during an early stage of processing.

Highlights

One of the most remarkable abilities of the human visual system is recognizing individual faces quickly and efficiently
Face perception is modulated by categorical information in faces, i.e., discrimination of two faces is easier when the faces straddle a category boundary than when they belong to the same category[7], which is a phenomenon known as categorical perception (CP)
event-related potential (ERP) (i.e., N170 and visual mismatch negativity (vMMN)) that were elicited by the face stimuli in the visual oddball task

Summary

Introduction

One of the most remarkable abilities of the human visual system is recognizing individual faces quickly and efficiently. The vMMN provides an ideal tool for determining whether CP that is induced by learned face categories occurs automatically during the early pre-attentive processing stage. We first examined whether newly acquired categories could affect individuals’ perception of human faces using an AB-X discrimination task, and we investigated whether face CP occurs automatically during the pre-attentive processing stage using a visual oddball task and electroencephalogram (EEG) recording. In the ERP task, we hypothesized that if newly learned categories automatically affect face perception during the pre-attentive stage, the vMMN for the deviant faces whose acquired category differs from that of the standard faces would be stronger than that for the deviants from the same category as the standard stimuli

Methods

Results

Conclusion