How chimpanzees look at pictures: A comparative eye-tracking study

Fumihito Kano, Masaki Tomonaga

アイ・トラッキングの手法を用いて、ヒトとチンパンジーの眼球運動の比較研究を行った。この試みは世界に先駆けて本研究が初めてである。実験では、ヒト、チンパンジー、その他様々な動物の全身画像を観察中の、ヒト、チンパンジー被験者の眼球運動を記録した。両種の眼球運動は極めてよく類似していたが、同時に興味深い差異も明らかとなった。類似点１．両種とも、体の部位の中でとくに顔を長く注視した。２．両種とも、写真を提示した直後（220ms程度）に顔を注視することが多かった。相違点１．チンパンジーの注視点の移動（サッカード運動）はヒトよりも頻繁で、より大きく動く（角度）ことが多かった。２．チンパンジーが写真の顔部位を注視する一回あたり持続時間は平均300 msでヒトの平均680 msに比べはるかに短かった。

The proceedings of the royal society B

Surprisingly little is known about the eye movements of chimpanzees, despite the potential contribution of such knowledge to comparative cognition studies. Here, we present the first examination of eye tracking in chimpanzees. We recorded the eye movements of chimpanzees as they viewed naturalistic pictures containing a full-body image of a chimpanzee, a human, or another mammal; results were compared with those from humans. We found a striking similarity in viewing patterns between the two species. Both chimpanzees and humans looked at the animal figures longer than at the background and at the face region longer than at other parts of the body. The face region was detected at first sight by both species when they were shown pictures of chimpanzees and of humans. However, the eye movements of chimpanzees also exhibited distinct differences from those of humans: the former shifted the fixation location more quickly and more broadly than the latter. In addition, the average duration of fixation on the face region was shorter in chimpanzees than in humans. Overall, our results clearly demonstrate the eye-movement strategies common to the two primate species and also suggest several notable differences manifested during the observation of pictures of scenes and body forms.

http://rspb.royalsocietypublishing.org/content/early/2009/02/27/rspb.2008.1811.full.pdf+html

Copyright(C) 2009 PRI ().