Abstract
It is well known that the appearance of a new object in the visual field can capture attention, allowing it to be perceptually processed faster than objects that have been visible for some time. However, there are countless situations, such as walking down a busy Manhattan sidewalk, when new objects (people) appear continuously, but are almost completely ignored. Here, we assess whether the ability of a new object to capture attention depends upon its behavioral significance. We hypothesize that the potency of attentional capture decreases as the odds that a new visual object requires visual processing decreases. 4 Ss performed a modified version of the traditional attentional capture task of Yantis et al (1984). Ss searched for then discriminated a target object amongst 3 distractors. The target could have either just appeared (new object) or had been present for some time, initially masked (old object). In the traditional task, the odds of any object being the target are the same whether old or new. In our task, Ss viewed 4 letters, 3 old and 1 new, in 3 different conditions that differed in the probability of the target being the new object (50%, 25%, or 7.7%). Participants were informed of these odds prior to testing. In one version of the task, the location of the new object was predictable as soon as the 3 original objects appeared. The attentional capture effect decreased as the probability of the new object being the target decreased (50%: 43ms, 7.7%: 11ms). In the second version of the task, the location of the new object was not predictable. Here, the attention capture effect was reduced from 122ms to 72ms. These results support the hypothesis that the potency of attentional capture is modulated by the behavioral relevance of the suddenly appearing object. Manipulating the importance of a new object in a laboratory attention task may model the visual filtering processes brought to bear when navigating a Manhattan sidewalk.
Supported by SCORE (NIGMS) and RCMI (NCRR)