A search advantage for faces learned in motion

Karin S. Pilz, Ian M. Thornton, Heinrich H. Bülthoff

Recently there has been growing interest in the role that motion might play in the perception and representation of facial identity. Most studies have considered old/new recognition as a task. However, especially for non-rigid motion, these studies have often produced contradictory results. Here, we used a delayed visual search paradigm to explore how learning is affected by non-rigid facial motion. In the current studies we trained observers on two frontal view faces, one moving non-rigidly, the other a static picture. After a delay, observers were asked to identify the targets in static search arrays containing 2, 4 or 6 faces. On a given trial target and distractor faces could be shown in one of five viewpoints, frontal, 22 degrees or 45 degrees to the left or right. We found that familiarizing observers with dynamic faces led to a constant reaction time advantage across all setsizes and viewpoints compared to static familiarization. This suggests that non-rigid motion affects identity decisions even across extended periods of time and changes in viewpoint. Furthermore, it seems as if such effects may be difficult to observe using more traditional old/new recognition tasks.