Matt Craddock, University of Liverpool

Rebecca Lawson, University of Liverpool

Two experiments examined the attainment of size constancy in haptic object recognition. In Experiment 1, participants named one of three exemplars (standard size and shape, different size, and different shape exemplars) of 36 categories of real, familiar objects. They then performed an old/new recognition task based on object identity on the standard exemplars of all 36 objects. Half of the participants performed both blocks visually; the other half performed both blocks haptically. Participants were able to efficiently recognise unusually sized objects haptically, consistent with previous findings of good recognition of small-scale models of stimuli (Lawson, in press). However, both visual and haptic recognition was impaired when objects changed size or shape between blocks. In Experiment 2, participants performed a short-term haptic matching task using 3D plastic models of familiar objects. Again, there was a moderate cost when objects changed size. Like visual object recognition, haptic object recognition exhibits a significant but modest cost of attaining size constancy.

Under review.