Comparing view sensitivity in shape discrimination to shape sensitivity in view discrimination

Rebecca Lawson, University of Liverpool

Heinrich H. Bülthoff, Max Planck Institut für biologische Kybernetik

Three picture-picture matching studies contrasted the effects of a view change on our ability to detect a shape change (Experiments 1 and 2) and the effects of a shape change on our ability to detect a view change (Experiment 3). In each study, view changes and shape changes both influenced performance. However shape changes had more influence than view changes in the shape-change detection task. Conversely, view changes were more influential when the task was to detect view changes. Participants could thus often discriminate between the effects of shape changes and view changes. The disruptive effect of task-irrelevant changes (view changes in the first two studies; shape changes in the final study) does not support Stankiewicz's (2002) claim that information about viewpoint and about shape can be estimated independently by human observers. However the greater effect of variation in the task-relevant than the task-irrelevant dimension indicates that observers were moderately successful at disregarding irrelevant changes.

Perception and Psychophysics, (2006), 68, 655-673.