Effects of Two-Dimensional Noise and Feature Configuration on the Recognition of Faces In Capuchin Monkeys (Cebus apella)
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Face recognition in Old World monkeys is remarkably similar to that of humans, but relatively little is known about this ability in New World monkeys, such as capuchins (Cebus apella). The purpose of this study was to investigate the visual information capuchin monkeys use to recognize faces. In order to study this perceptual and cognitive ability, the animals were trained to simultaneously discriminate between grayscale pictures of both humans and nonhuman primates and non-face objects. Two-dimensional visual noise was then introduced into both images to decrease face recognition (cf. Harmon & Julesz, 1973). The animals were able to make the discriminations even at a high level of image degradation, suggesting capuchins are highly sensitive to physical variations such as contrast and value distribution. In order to minimize variations in the physical properties of the stimuli, the facial features were randomly scrambled and presented with an original intact face. In this second simultaneous discrimination task, none of the animals could discriminate between the scrambled and intact face at a level significantly above chance. The capuchins acquired the ability to discriminate only after repeated presentations of the same intact and scrambled stimuli.
Franklin and Marshall College Archives, Undergraduate Honors Thesis 2007
- F&M Theses Collection