Attentional capture by motion onsets is spatially imprecise

in stampa

Using straight translatory motion of a visual peripheral cue in the frontoparallel plane, and probing target discrimination at different positions along the cue's motion trajectory, we found that target orientation discrimination was slower for targets presented at or near the position of motion onset (4.2 degrees off centre), relative to the onset of a static cue (Experiment 1), and relative to targets presented further along the motion trajectory (Experiments 1 and 2). Target discrimination was equally fast and accurate in the moving cue conditions relative to static cue conditions at positions further along the cue's motion trajectory (Experiment 1). Moreover, target orientation discrimination was not slowed at the same position, once this position was no longer the motion onset position (Experiment 3), and performance in a target colour-discrimination task was not slowed even at motion onset (Experiment 4). Finally, we found that the onset location of the motion cue was perceived as being shifted in the direction of the cue's motion (Experiment 5). These results indicate that attention cannot be as quickly or precisely shifted to the onset of a motion stimulus as to other positions on a stimulus' motion trajectory.