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Abstract

We investigated whether familiar, 3-D objects are
categorically perceived in the same way that other visual stimuli (e.g., colour and faces) are perceived as categorical. A continuum of shape change between fifteen pairs of objects was created and the images along the continuum were used as stimuli. In Experiment 1 participants were first required to discriminate pairs of images of objects that lay along the shape continuum. Then participants were asked to classify each morph-image into one of two pre-specified shapes. We found evidence for categorical perception in some but not all of our object pairs. In Experiment 2 we lloked in more detail at
specific object pairs by increasing the difficulty of the
discrimination task and found that more object pairs were
categorically perceived. In Experiment 3 similarity ratings for each object pair were collected. These similarity scores correlated with the degree of perceptual categorisation found for the object pairs. Our findings suggest that familiar objects are perceived
categorically and that categorical perception is closely tied to inter-object perceptual similarity.