Abstract
Purpose. Extremely familiar faces (e.g. one's own face) can be found rapidly in visual search tasks (e.g. Tong and Nakayama, 1999). We now investigate whether similar benefits can be found for faces of other levels of familiarity (for example, moderately famous faces). Stimuli and Procedure. In all conditions, participants searched for a target face among a set of novel distractor faces. A present/absent response was required (targets were present on half the trials). We chose the target faces to include various levels of familiarity (e.g. unknown, familiar, well-known, famous). Half the trials were standard visual search trials and the other half were presented in a novel “overlay condition”. In this condition, each stimulus was presented behind a transparent novel face (40% transparency). This condition, which requires the observer to segregate the two images, was created to put unique demands on the face-recognition system. Results. In our standard search condition, search benefits increased as a function of familiarity. In other words, each increase in familiarity yields additional search benefits. However, in the overlay condition such a quantitative performance increase was not found. In this condition, we found search benefits only for highly familiar faces. Discussion. Task demands determine how familiarity impacts search performance. In some tasks, each increase in target familiarity leads to better performance. But, in other cases, increases in familiarity have little or no effect until the stimuli are extremely familiar. We discuss these results in terms of the mental representations required to facilitate task performance.