Development of differential sensitivity for shape changes resulting from linear and nonlinear planar transformations

Bart Ons

Laboratory of Experimental Psychology, University of Leuven (K.U. Leuven), Tiensestraat 102, box 3711, BE-3000 Leuven, Belgium

bart.ons@psy.kuleuven.be

Johan Wagemans

Laboratory of Experimental Psychology, University of Leuven (K.U. Leuven), Tiensestraat 102, box 3711, BE-3000 Leuven, Belgium

johan.wagemans@psy.kuleuven.be

 
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Abstract. A shape bias for extending names to objects that look visually similar has been commonly accepted but it is hard to define which kind of shape dissimilarities are diagnostic for the identity of an object. Here, we present a transformational approach to describe shape differences that can incorporate many significant shape features. We introduce two kinds of transformations: one kind concerns linear transformations of the image plane (affine transformations), generally limiting shape variations within borders of basic-level categories; the other kind concerns nonlinear continuous transformations of the image plane (topological transformations), allowing all kinds of shape variation crossing and not crossing the borders of basic-level categories. We administered stimulus pairs differing in these shape transformations to children of 3 to 7 years old in a delayed match-to-sample task. With increasing age, especially between 5 and 6 years, children became more sensitive to the topological deformations that are relevant for between-category distinctions, indicating that acquired categorical knowledge in early years induced perceptual learning of the relevant generic shape differences between categories.


Cite as: Ons B, Wagemans J, 2011, "Development of differential sensitivity for shape changes resulting from linear and nonlinear planar transformations" i-Perception 2(2) 121–136
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DOI: 10.1068/i0407

ISSN: 2041-6695 (electronic only)

Copyright: Copyright is retained by the author(s) of this article. This open-access article is distributed under a Creative Commons Licence, which permits noncommercial use, distribution, and reproduction, provided the original author(s) and source are credited and no alterations are made.
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