Japanese monkeys' cardiac responses to visual depth
Keikichi Hayashibe, Masatoshi Hara, Keiichiro Tsuji, Tetsuro Matsuzawa
The present study examined the heart rate changes which occurred in the visual depth situation of Japanese monkeys (Macaca Juscata). Four animals were tested over the first four weeks of age in the visual pitfall designed as a modification of the visual cliff. The infant monkeys showed heart rate reduction in the depth con dition. This reduction was observed from the first week and became remarkable at the third week. There were no differences in heart rate change between monocular and binocular vision. These findings suggest that the Japanese monkey can discrirni nate visual depth shortly after birth and that the heart rate reduction depends upon the fear of visual depth, not upon the novelty of the situation.