Emil W. Menzel

Selection of food by size in the chimpanzee, and comparison with human judgments.

Adult chimpanzees, given access to an array of pieces of banana, select the pieces in order of size, larger pieces being taken first. Selection is mediated by perceived sizes, and the responses correspond closely to human visual judgment of size.

EFFECTS OF SIZE AND SHAPE OF APERTURE UPON VISUAL EXPLORATION BY RHESUS MONKEYS.

The amount of time that adult rhesus monkeys (N = 10) looked out from an enclosed box through a circular peephole increased with diameter of aperture and decreased with thickness of aperture. Choices between two peepholes were similarly a function of differences in diameter. With rectangular apertures, the horizontal extent was more important than the vertical extent in maintaining looking. Throughout 5 experiments the crucial variable seemed to be the effective area of the available visual field or fields.