The nature of shape constancy mechanisms as revealed by shape priming

Abstract

Five shape priming experiments are reported in which the target was either a five- or six-sided line-drawn figure and participants made a speeded two-alternative forced-choice judgment about the target's number of sides. On priming trials, the target was preceded by a briefly presented smaller line figure (the prime) and performance on these trials was gauged relative to a no-prime condition. In the first two experiments, primes were rendered invisible by the presentation of a backwards visual noise mask, respectively for a short (∼40 ms) or long duration (∼93 ms). No reliable priming effects arose under masked conditions. When these experiments were repeated without the mask, participants were speeded when the prime and target were related by a rigid through-the-plane rotation but not when the prime was a nonrigid, stretched version of the target. The same pattern of priming effects arose when, in a final experiment, novel irregular shapes were used. Collectively, the data reveal the operation of shape constancy mechanisms that are particularly sensitive to shape rigidity. The findings suggest that the visual system attempts to secure a correspondence between the rapid and successive presentations of the prime and the target by matching shapes according to a rigidity constraint.

On interference between target and noise in visual stimuli

“…Some investigators have presented the target stimulus and the noise after one another in time or have alternated them in time (Liberman et al, 2014;Mattson et al, 1994;Mitra et al, 2014;Quinlan & Allen, 2018). In this connection it should be pointed out that interference may also occur across time.…”

“…Typically the adding of noise has a deleterious effect on the performance on the task in question (Attwell et al, 2021;Beattie et al, 2011;Dakin et al, 2018;Dewhurst et al, 2018;Emadi & Esteki, 2013;Hall et al, 2014;Kuboki et al, 2017;Mareschal et al, 2010;Milner & Michalski, 2003;Pelli et al, 2004). The effect of visual noise has commonly been attributed to factors in the visual system or has been discussed in relation to such factors (e.g., Asher et al, 2021;Attwell et al, 2021;Cropper et al, 2020;Dakin et al, 2018;Emadi & Esteki, 2013;Hall et al, 2014;Hall & McAnany, 2017;Jones et al, 2003;Kruger et al, 1986;Kuboki et al, 2017;Legge et al, 1987;Luber et al, 2020;Pardhan et al, 1996;Quinlan & Allen, 2018;Rainer et al, 2004;Salmela & Laurinen, 2009;Stuke et al 2021). However, it has become clear that in the case of stimuli containing several stimulus elements, such as, e.g., in the case of visual masking and visual crowding, there may be interference between the elements (Skottun, 2018a, b, c, d).…”

A Pluralist Perspective on Shape Constancy

“…In other words, by around 110 ms, the visual system tokened a representation-type that was invariant to changes in picture-plane orientation (see also Quinlan and Allen [2018]). Reprinted with permission from (Baker and Kellman [2018]).…”