title: Efficient search for a face by chimpanzees (Pan troglodytes).
abstract: The face is quite an important stimulus category for human and nonhuman primates in their social lives. Recent advances in comparative-cognitive research clearly indicate that chimpanzees and humans process faces in a special manner; that is, using holistic or configural processing. Both species exhibit the face-inversion effect in which the inverted presentation of a face deteriorates their perception and recognition. Furthermore, recent studies have shown that humans detect human faces among non-facial objects rapidly. We report that chimpanzees detected chimpanzee faces among non-facial objects quite efficiently. This efficient search was not limited to own-species faces. They also found human adult and baby faces--but not monkey faces--efficiently. Additional testing showed that a front-view face was more readily detected than a profile, suggesting the important role of eye-to-eye contact. Chimpanzees also detected a photograph of a banana as efficiently as a face, but a further examination clearly indicated that the banana was detected mainly due to a low-level feature (i.e., color). Efficient face detection was hampered by an inverted presentation, suggesting that configural processing of faces is a critical element of efficient face detection in both species. This conclusion was supported by a simple simulation experiment using the saliency model.
authors.affiliation: Primate Research Institute, Kyoto University, 41-2 Kanrin, Inuyama, Aichi 484-8506, JAPAN.
authors.forename: Masaki
authors.initials: M
authors.lastname: Tomonaga
authors.affiliation: Niigata University of International and Information Studies, 3-1-1 Mizukino, Nishi-ku, Niigata, Niigata 950-2292, JAPAN.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Imura
mesh_terms: D000818:Animals; D005145:Face; D005260:Female; D007858:Learning; D002679:Pan troglodytes / Q000502:physiology*; D010775:Photic Stimulation; D021641:Recognition, Psychology; D014796:Visual Perception