Rebecca Lawson, University of Liverpool

A sequential matching task was used to compare how the difficulty of shape discrimination influenced the achievement of object constancy for depth rotations across haptic and visual object recognition. Stimuli were nameable, 3D plastic models of familiar objects (e.g., bed, chair) and morphs midway between these endpoint shapes (e.g., a bed-chair morph). The two objects presented on a trial were either both placed at the same orientation or were rotated by 90? relative to each other. Discrimination difficulty was increased by presenting more similarly shaped objects on mismatch trials (easy: bed then lizard; medium: bed then chair; hard: bed then bed-chair morph). For within-modal visual matching, orientation changes were most disruptive when shape discrimination was hardest. This interaction for 3D objects replicated the interaction reported in earlier studies presenting 2D pictures of the same objects (Lawson & Bülthoff, 2008). In contrast, orientation changes and discrimination difficulty had additive effects on within-modal haptic and crossmodal visual-to-haptic matching whilst crossmodal haptic-to-visual matching was orientation-invariant. These results suggest that the cause of orientation-sensitivity may differ for visual and haptic object recognition.

Journal of Experimental Psychology: Human Perception and Performance, (2009), 35, 911-930.