Perception of the Thatcher illusion by the squirrel monkey (Saimiri sciureus)(Summary of Awarded Presentation at the 27th Annual Meeting)

抄録

We examined whether the squirrel monkey can perceive Thompson's Thatcher illusion. In the experiment, the monkey was required to discriminate a target face from three kinds of distractor stimuli whose particular facial features were different from those of the target. Because both faces were tilted at angles of either 45, 135, 225, or 315 degrees, there were four combinations of upright and inverted face presentations. The results revealed that when both faces were inverted and the eyes of the distractor face were reversed from the target face, the monkey's discrimination learning was obstructed more than under other conditions. Thus, these results suggest that the squirrel monkey can perceive the Thatcher illusion. It seems reasonable to suppose that the monkey can utilize information about facial configuration.