Rigid facial motion influences featural, but not holistic, face processing

Abstract

We report three experiments in which we investigated the effect of rigid facial motion on face processing. Specifically, we used the face composite effect to examine whether rigid facial motion influences primarily featural or holistic processing of faces. In Experiments 1-3, participants were first familiarized with dynamic displays in which a target face turned from one side to another; then at test, participants judged whether the top half of a composite face (the top half of the target/foil face aligned or misaligned with the bottom half of a foil face) belonged to the target face. We compared performance in the dynamic condition to various static control conditions in Experiments 1-3, which differed from each other in terms of the display order of the multiple static images or the inter-stimulus interval (ISI) between the images. We found that the size of the face composite effect in the dynamic condition was significantly smaller than that in the static conditions. In other words, the dynamic face display influenced participants to process the target faces in a part-based manner and consequently their recognition of the upper portion of the composite face at test became less interfered with by the aligned lower part of the foil face. The findings from the present experiments provide the strongest evidence to date to suggest that the rigid facial motion mainly influences facial featural, but not holistic, processing.

Figure 1

Examples of multi-dynamic (upper) and -static (lower) familiarization stimuli used in Experiment 1. Both are comprised of identical images, the only difference lies in the display order of these images. In the multiple-dynamic stimuli, the face viewpoint changes smoothly, while the order is randomized in the multi-static stimuli. The first and the last images in both stimuli were the same (i.e., profile view), in order to equalize the influence of the first and last image on the composite face recognition.

Figure 2

Examples of a target composite face (the top panel) and a foil composite face (the bottom panel). The two faces share the identical outer facial features, and only differ from each other in terms of the top halves of the inner face. Both target and foil composite faces are created by either fusing the top half of the target or foil face with the bottom half of another face to create aligned composite faces (left) or misaligning the top half of the target or foil face with the bottom half of another face to create misaligned composite faces (right).

Figure 3

Mean A' of each condition in Experiment 1, 2, &3. Error bars represent 1 SE.