The role of (other or self-) reference in the perception of expanding biological motion

Abstract

revious research has suggested that exocentric and egocentric perceptions are associated with different performances in various tasks. However it is unclear if the use of self-reference would differently affect the perception of expanding biological and rigid motion? Experiment 1 consisted in an exocentric velocity judgement between simultaneous expanding patterns--two rigid, two biological, or one of each. Results revealed more correct responses and lower reaction times for rigid (less complex) stimuli. Experiment 2 used the same stimuli in a self-based collision estimation. The observer had to judge whether an object moving towards his/her direction would pass him/her before or after a sound marker. Here, biological pattern elicited more accurate collision estimations. A high bias, speed overestimation, was verified in the presence of rigid objects. Reaction times did not differ between conditions. In an exocentric task the complexity of the motion seems to be the crucial factor. However in an egocentric task with higher potential for action, biological patterns elicited better responses, even when patterns were more complex.