Shape predominant effect in pattern recognition of geometric
figures of rhesus monkey
Yucui Chen, Weiwei Zhang, Zheng Shen *
Department of Psychology and National Laboratory on Machine Percept., Peking University, Beijing 100871, China
Received 6 February 2001; received in revised form 10 October 2001
Abstract
Three monkeys were trained successively with discrimination, concurrent matching to sample, and sameness–difference judgment
tasks in which learning curves were compared. Then, the display duration for the stimuli was shortened to 100, 50, and 30 ms
respectively to test the changes in accuracy and reaction time. All results in three experimental paradigms suggested consistently that
the geometric shape (triangle, circle, and square) plays a more predominant role than topological features (the hole inside of a figure
and the hole numbers) in monkey figure recognition. The results are different from the experiment by human subjects who presented
hole predominant in figure recognition. Therefore, the precedence in perception depends on subject species, stimulus set, and
ecological significance of the perceiving process. 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Rhesus monkey; Pattern recognition; Topological feature; Euclid geometric property; Species-specific effect
1. Introduction
The studies on pattern recognition of two-dimen-
sional (2D) images was a frontier of artificial intelligence
(AI) three decades ago, but the difference of visual
perception among machine, human, and non-human
primates remains to be revealed. AI pays attention to
machine perception, which usually starts from feature
detection with analysis of gray level, line finding, region
growing, geometric shape differentiation (Cohen & Fe-
igenbaum, 1982). On the contrary, Gestalt psychology
claims that human visual perception concerns predom-
inant processing of global features. The theory of global
predominance over local features was advanced on the
basis of findings which used compound stimulus pat-
terns with small lette