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Efficient search for a face by chimpanzees (Pan troglodytes).

Tomonaga M, Imura T - Sci Rep (2015)

Bottom Line: Both species exhibit the face-inversion effect in which the inverted presentation of a face deteriorates their perception and recognition.They also found human adult and baby faces--but not monkey faces--efficiently.This conclusion was supported by a simple simulation experiment using the saliency model.

View Article: PubMed Central - PubMed

Affiliation: Primate Research Institute, Kyoto University, 41-2 Kanrin, Inuyama, Aichi 484-8506, JAPAN.

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.

No MeSH data available.


The female chimpanzee Chloe performing the visual search task.She was searching for a chimpanzee face. Photo Courtesy: Masaki Tomonaga (Primate Research Institute, Kyoto University).
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f1: The female chimpanzee Chloe performing the visual search task.She was searching for a chimpanzee face. Photo Courtesy: Masaki Tomonaga (Primate Research Institute, Kyoto University).

Mentions: In the present series of experiments, we examined efficient searching for faces by three adult chimpanzees using visual search tasks910363738 (Fig. 1). In the first experiment, the chimpanzees were trained to find a picture of a chimpanzee face, a banana, a car, and a house among distractors from various object categories (Fig. 2). All target categories were familiar to our chimpanzee participants, but we predicted that only a face would be detected efficiently. In the second experiment, we manipulated low-level and higher-order features to identify the contributions of these features, particularly the role of first-order spatial configuration of the face. To confirm the results of the second experiment, we conducted simple simulation experiments using the saliency-map model3940. This model simulates attention based on a set of low-level features, such as colors, contrasts, line orientations, etc. In the last two experiments, we examined the generality and limitations of efficient searching for facial stimuli among non-face objects by presenting other-species faces as well as profiles and outer features of faces.


Efficient search for a face by chimpanzees (Pan troglodytes).

Tomonaga M, Imura T - Sci Rep (2015)

The female chimpanzee Chloe performing the visual search task.She was searching for a chimpanzee face. Photo Courtesy: Masaki Tomonaga (Primate Research Institute, Kyoto University).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4504146&req=5

f1: The female chimpanzee Chloe performing the visual search task.She was searching for a chimpanzee face. Photo Courtesy: Masaki Tomonaga (Primate Research Institute, Kyoto University).
Mentions: In the present series of experiments, we examined efficient searching for faces by three adult chimpanzees using visual search tasks910363738 (Fig. 1). In the first experiment, the chimpanzees were trained to find a picture of a chimpanzee face, a banana, a car, and a house among distractors from various object categories (Fig. 2). All target categories were familiar to our chimpanzee participants, but we predicted that only a face would be detected efficiently. In the second experiment, we manipulated low-level and higher-order features to identify the contributions of these features, particularly the role of first-order spatial configuration of the face. To confirm the results of the second experiment, we conducted simple simulation experiments using the saliency-map model3940. This model simulates attention based on a set of low-level features, such as colors, contrasts, line orientations, etc. In the last two experiments, we examined the generality and limitations of efficient searching for facial stimuli among non-face objects by presenting other-species faces as well as profiles and outer features of faces.

Bottom Line: Both species exhibit the face-inversion effect in which the inverted presentation of a face deteriorates their perception and recognition.They also found human adult and baby faces--but not monkey faces--efficiently.This conclusion was supported by a simple simulation experiment using the saliency model.

View Article: PubMed Central - PubMed

Affiliation: Primate Research Institute, Kyoto University, 41-2 Kanrin, Inuyama, Aichi 484-8506, JAPAN.

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.

No MeSH data available.