Trapped in a tight spot: Scaling effects occur when, according to the action-specific account, they should not, and fail to occur when they should

Elizabeth S Collier,Rebecca Lawson

doi:10.3758/s13414-017-1454-y

Abstract

The action-specific account of perception claims that what we see is perceptually scaled according to our action capacity. However, it has been argued that this account relies on an overly confirmatory research strategy—predicting the presence of, and then finding, an effect (Firestone & Scholl, 2014). A comprehensive approach should also test disconfirmatory predictions, in which no effect is expected. In two experiments, we tested one such prediction based on the action-specific account, namely that scaling effects should occur only when participants intend to act (Witt, Proffitt, & Epstein, 2005). All participants wore asymmetric gloves in which one glove was padded with extra material, so that one hand was wider than the other. Participants visually estimated the width of apertures. The action-specific account predicts that the apertures should be estimated as being narrower for the wider hand, but only when participants intend to act. We found this scaling effect when it should not have occurred (Exp. 1, for participants who did not intend to act), as well as no effect when it should have occurred (Exp. 2, for participants who intended to act but were given a cover story for the visibility and position of their hands). Thus, the cover story used in Experiment 2 eliminated the scaling effect found in Experiment 1. We suggest that the scaling effect observed in Experiment 1 likely resulted from demand characteristics associated with using a salient, unexplained manipulation (e.g., telling people which hand to use to do the task). Our results suggest that the action-specific account lacks predictive power.

Highlights

The action-specific account of perception claims that what we see is perceptually scaled according to our action capacity
One of the earliest findings that suggested that visual perception scales according to participants’ action capacity was that participants estimated hills as steeper after vigorous exercise than before exercising (Proffitt, Bhalla, Gossweiler, & Midgett, 1995, Exp. 5)
Proffitt and Linkenauger (2013) suggested that perception can be scaled according to three components of action capacity: the bioenergetic cost of acting, performance variability, and action capacity pertaining to the functional morphology of the body

Summary

Introduction

The action-specific account of perception claims that what we see is perceptually scaled according to our action capacity. The Intention-to-Act group (n = 18) completed the action capacity task before the perceptual task, and on each trial of the perceptual task, they were asked whether they thought they could fit their hand through the aperture before estimating its width.

Results

Conclusion