Abstract
Configuration and Distance Interact to Determine Object- or Space-Based Attentional Deployment
Purpose. An “object advantage” prevails when comparing object-based attentional shifts over the same distance within a bar vs. space-based shifts across bars1. Following up on findings that attention shifts are facilitated by line tracing2, we tested the hypothesis that the object advantage is due to a facilitation of such shifts along the stimuli.
Methods. Stimuli were pairs of bars {e.g. | |}, brackets {e.g. [ ]}, or arcs {e.g. ( )} with the distance between endpoints within a member equal to the distance across the endpoints of a pair of members. Attentional cues appeared briefly at one end of one of the members of a pair each trial. On 20% of the trials no target appeared. The cues were valid on 75% of the trials when a target appeared and invalid for the rest. On invalidly cued trials, the target appeared equally often in either the same stimulus or else the other stimulus of a pair. Participants responded as quickly as possible to the onset of the target.
Results. Valid cueing yielded faster RTs for all stimulus types. For straight lines, results replicated prior findings1: invalid-cue costs were larger for across- than within-object shifts. A similar, smaller, effect occurred for arcs, but no effect occurred for brackets.
Conclusions. The object-based advantage of attentional deployment is subject to Gestalt configurational factors such as good curve and good continuation. In the absence of such factors, as in the case of brackets, space-based deployment seems to prevail.
1.
EglyR.DriverJ.RafalR. D.(1994). Shifting visual attention between objects and locations: Evidence from normal and parietal lesion subjects. J. Exp. Psychol.: Gen. 123: 161–177.
2.
AvrahamiJ.(1999). Objects of attention, objects of perception. Percept. & Psychophys. 61, 1604–1612.