Is Visual Perceptual Narrowing an Obligatory Developmental Process?

Andrea Sorcinelli,Athena Vouloumanos

doi:10.3389/fpsyg.2018.02326

Abstract

Perceptual narrowing, or a diminished perceptual sensitivity to infrequently encountered stimuli, sometimes accompanied by an increased sensitivity to frequently encountered stimuli, has been observed in unimodal speech and visual perception, as well as in multimodal perception, leading to the suggestion that it is a fundamental feature of perceptual development. However, recent findings in unimodal face perception suggest that perceptual abilities are flexible in development. Similarly, in multimodal perception, new paradigms examining temporal dynamics, rather than standard overall looking time, also suggest that perceptual narrowing might not be obligatory. Across two experiments, we assess perceptual narrowing in unimodal visual perception using remote eye-tracking. We compare adults’ looking at human faces and monkey faces of different species, and present analyses of standard overall looking time and temporal dynamics. As expected, adults discriminated between different human faces, but, unlike previous studies, they also discriminated between different monkey faces. Temporal dynamics revealed that adults more readily discriminated human compared to monkey faces, suggesting a processing advantage for conspecifics compared to other animals. Adults’ success in discriminating between faces of two unfamiliar monkey species calls into question whether perceptual narrowing is an obligatory developmental process. Humans undoubtedly diminish in their ability to perceive distinctions between infrequently encountered stimuli as compared to frequently encountered stimuli, however, consistent with recent findings, this narrowing should be conceptualized as a refinement and not as a loss of abilities. Perceptual abilities for infrequently encountered stimuli may be detectable, though weaker compared to adults’ perception of frequently encountered stimuli. Consistent with several other accounts we suggest that perceptual development must be more flexible than a perceptual narrowing account posits.

Highlights

Humans become less sensitive to distinctions and cross-modal correspondences between less frequently encountered stimuli over time, in a developmental process termed perceptual narrowing
Using the same metric which famously showed that adults discriminate between human but not monkey faces, we found that adults were able to discriminate both frequent human and infrequent monkey faces
Using the same metric which famously showed that adults discriminate between human but not monkey faces, we found that again adults were able to discriminate both frequent human and infrequent monkey faces

Summary

Introduction

Humans become less sensitive to distinctions and cross-modal correspondences between less frequently encountered stimuli over time, in a developmental process termed perceptual narrowing. The first evidence for perceptual narrowing came from speech perception: younger infants could discriminate between native and non-native speech sounds, whereas older infants became less sensitive to non-native speech (Werker and Tees, 1984; Kuhl et al, 1992). It was evidence from face perception which suggested that perceptual narrowing was not limited to speech perception, and instead was a fundamental and perhaps obligatory developmental process. Perceptual narrowing has been suggested to be a fundamental and general aspect of perceptual development as it has been observed in multiple modalities and under varied conditions

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