WHO:	Steven Jax , Penn State University (Grad Student visiting Hayhoe lab)
TOPIC:	Sequential Effects in Reaching around Obstacles: The Obstacle-Perseveration Effect
ABSTRACT:	Current theories of manual obstacle avoidance do not predict sequential effects in obstacle avoidance because the theories assume, explicitly or implicitly, that the way a movement is planned does not depend on what movements were performed before. The goal of the present research was to determine whether sequential effects do in fact occur in reaching around obstacles. We asked participants to perform reaching movements between targets in the presence of or in the absence of an intervening obstacle. Results from four experiments showed significant sequential effects. When obstacle-present and obstacle-absent trials were intermixed within a block of trials, the hand paths in the obstacle-absent trials were more curved than when no obstacle was ever present. This obstacle-perseveration (OP) effect appears to be due to difficulties in switching from an obstacle-avoidance mode to a non-obstacle-avoidance mode of performance. In support of this interpretation, the effect does depend on the probability of obstacle-present trials (Experiment 2) but does not depend on the randomness of trial switches (Experiments 3 and 4). 
WHEN:	3/1/2004 12:00:00 PM
WHERE:	Meliora 269

Events Homepage