Doctoral Disseration Improvement: The Role of Binocular Vision in Primate Evolution

Duke University, Durham NC

Investigators

Abstract

Most vertebrates possess some overlap of the right and left visual fields. The region of overlap, the binocular field, contains unique visual cues that provide an accurate estimate of distance and three-dimensional shape. The fact that animal's might use these cues to guide behavior has several interesting implications to the study of primate evolution. While there is an abundance of data suggesting that many animals perceive binocular cues, there is little evidence demonstrating binocular information is advantageous during ecologically relevant behaviors. Determining the conditions under which binocular cues are useful will be a first step in answering why most animals have binocular vision and why primates in particular have such a wide region of overlap. This project tests whether binocular information is more useful for grasping than reaching, and whether biocular cues are only useful in tasks requiring a high degree of precision. Kinematic analyses will be used to evaluate the effect of removing binocular cues on the locomotion of two primates, two marsupials, and two carnivorans in three conditions, simple locomotion, precision reaching, and precision grasping. These kinematic data will be used to evaluate the praxic hypothesis, the idea that the binocular field is correlated with the region of space over which animals make visually guided movements. The praxis hypothesis has the potential to relate eye orientation to behavioral ecology in a diverse array of species. More specifically, it provides a proximate explanation for theories of primate origins such as the nocturnal visual predation hypothesis and fine-branch arboreal hypothesis. In addition to its importance for studies of primate evolution this project will have a more general societal impact. It will encourage undergraduate participation in science by involving Duke students in data collection and analysis. Additionally, the results of this project will be included in teaching at both an academic level through college courses and public education at local schools and science museums.