Abstract
The influence of facial organization on discrimination of a local facial feature was investigated using a visual search task. Subjects searched for a down-turned mouth in an array of one to six faces. Faces differed only in the presence (down-turned mouth) or absence (up-turned mouth) of the target feature, with target-present faces appearing unusual when viewed upright. In Experiment 1, subjects searched for the target mouth in upright normal faces, inverted normal faces, and faces in which the internal features were scrambled. Search was faster in the upright normal condition compared to the scrambled and inverted normal conditions. This suggests that the configural processing associated with upright faces facilitates local feature discrimination when an emergent feature such as facial expression can distinguish the target from distractors, and further, that the configural information giving rise to perception of facial expression is lost in the inverted face. However, a comparison of scrambled and inverted normal faces revealing faster search rates for scrambled faces suggests that some form of configural information remains in inverted faces and impedes the discrimination of local features. In Experiment 2 this result was confirmed and extended with a demonstration that external features contribute to configural processing of the face. Faster search rates were found for inverted scrambled faces in comparison with upright scrambled faces which in turn were searched faster than inverted normal faces. The overall pattern of results suggests that inverted faces, as well as upright faces, are first processed holistically. This obligatory holistic processing prevents immediate access to local feature information even when such constituent information is required by the task.
This research was supported by an Otago Research Grant.