Perceptual constancy with a novel sensory skill.

Liam J Norman,Lore Thaler

doi:10.1037/xhp0000888

Abstract

Making sense of the world requires perceptual constancy—the stable perception of an object across changes in one’s sensation of it. To investigate whether constancy is intrinsic to perception, we tested whether humans can learn a form of constancy that is unique to a novel sensory skill (here, the perception of objects through click-based echolocation). Participants judged whether two echoes were different either because: (a) the clicks were different, or (b) the objects were different. For differences carried through spectral changes (but not level changes), blind expert echolocators spontaneously showed a high constancy ability (mean d′ = 1.91) compared to sighted and blind people new to echolocation (mean d′ = 0.69). Crucially, sighted controls improved rapidly in this ability through training, suggesting that constancy emerges in a domain with which the perceiver has no prior experience. This provides strong evidence that constancy is intrinsic to human perception.

Highlights

Public Significance Statement This study shows that people who learn a new skill to sense their environment - here: listening to sound echoes - can correctly represent the physical properties of objects
We considered the effect of echolocation experience in this context by testing expert echolocators (EEs) as well as blindfolded sighted controls (SCs) and blind controls (BCs) with no prior experience in echolocation
Each subject group performed very well (Figure 5a), and, as shown with one-sample t tests, each group performed significantly better than chance (SC: M ϭ .96, t(9) ϭ 28.88, p Ͻ .001, d ϭ 9.13; BC: M ϭ .93, t(9) ϭ 15.06, p Ͻ .001, d ϭ 4.76; EE: M ϭ 1.00, t(2) ϭ 134.01, p Ͻ .001, d ϭ 77.36)

Summary

Introduction

Public Significance Statement This study shows that people who learn a new skill to sense their environment - here: listening to sound echoes - can correctly represent the physical properties of objects. For expert echolocators (EEs), the level and spectrum of an echo carry information that can be used to recover the physical properties of the reflecting object such as its size, shape, and material (e.g., Milne et al, 2014, 2015; Teng & Whitney, 2011; Yu et al, 2018). This is possible because those properties of the reflecting object determine how much energy of the echolocator’s click is reflected at different wavelengths. Variations in the spectrum of the echo can vary for similar reasons— either because there is variation in the spectrum of the click or variation in the physical properties of the object (e.g., shape, material, size)

Methods

Results

Conclusion