Abstract
A well-known result in visual search is that targets are found more quickly among familiar distractors than among novel distractors (e.g., Wolfe, 2001, Percept & Psychophys). In such tasks, familiarity is confounded with category membership; more efficient search through familiar distractors may be due not only to their greater familiarity, but their being grouped together as members of the same conceptual category. The present experiments (1) manipulate category membership while controlling for novelty and perceptual similarity, and (2) investigate the role of auditory labels in category effects in visual search.
Participants searched for a letter-like symbol among distractors that were either within-category (B and b), or between-category (B and p). Stimuli were presented in a within-subject mixed-trial design. Despite being matched precisely for perceptual similarity, targets were found more quickly among within-category distractors (Bb) than within-category distractors (Bb). A 90° rotation of the stimuli such that they no longer resembled letters eliminated the effect. Control conditions determined that rather than being a result of long-term practice grouping B's and b's into the same category, the conceptual grouping effect seems to emerge on-line, possibly due to differences in the inter-item competition for attention.
In a second series of experiments, it is shown that search for a known target (e.g., a 2 among 5s), is made easier by actually hearing the target label (“two”) even though participants already know what they are searching for. Labeling the distractors (“ignore fives”) produces a similar facilitation. Labels had no effect on rotated 2s and 5s.
Together, these experiments suggest that controlling for novelty and perceptual similarity, conceptual relations affect visual search performance, and verbal labels further enhance the degree to which categories penetrate perceptual processing.
Supported in part by the NSFGRF