Familiarity and pop-out in visual search

In this paper, we report that when the low-level features of targets and distractors are held constant, visual search performance can be strongly influenced by familiarity. In the first condition, a was the target amid as distractors, and vice versa. The response time increased steeply as a function of number of distractors (82 msec/item). When the same stimuli were rotated by 90° (the second condition), however, they became familiar patterns— and —and gave rise to much shallower search functions (31 msec/item). In the third condition, when the search was for a familiar target, (or ), among unfamiliar distractors, (or ), the slope was about 46 msec/item. In the last condition, when the search was for an unfamiliar target, (or ), among familiar distractors, s (or s), parallel search functions were found with a slope of about 1.5 msec/item. These results show that familiarity speeds visual search and that it does so principally when the distractors, not the targets, are familiar.