Joseph D. Cohen

Professor Emeritus of Psychology

Vision and visual perception; neuropsychology of vision and action; color perception; perceptual illusions; interactions of color in visual art

Joseph Cohen is an experimental psychologist with interests in visual perception. He uses psychophysical methods to explore the phenomenology of perception and to infer the underlying biological processes. Currently, he is exploring how people use visual information when they are trying to judge what the objects around them are and when they are acting on those objects, for example, walking towards, reaching for, or grasping them. Perception and action seem to use visual information in different ways. Some of the strongest evidence comes from stroke patients. Patients with damage in the inferotemporal cortex of the brain are unable to recognize objects in their environment visually, yet they can accurately reach out and grasp them. Patients with damage to the posterior parietal cortex can recognize objects, but they cannot readily move towards them or grasp them. Cohen and his students are investigating this dissociation in experimental participants with intact brains by comparing perceptual and visuomotor responses to three-dimensional visual illusions. His research has most recently been published in Neuropsychologia.

In work on color perception Cohen has investigated individual differences in the time course of color change following color adaptation (exposure to a colored light stimulus) and during recovery from adaptation, in both color-deficient observers and persons with normal color vision.  He also has a long standing interest in psychology and art, particularly in the understanding and use of color interactions by visual artists.

For several years, Cohen has been teaching a first-year seminar, Introductory Seminars in Psychology: Brain/Mind. The course draws on neurological case studies to explore how mind and behavior depend on the activity and structure of the brain. It considers central issues in psychology: the nature of the self and personal identity; the roles of conscious and unconscious processes in memory, perception, thought, and emotion; and the contributions of genetics and experience to cognitive and social development. In addition, he teaches visual and auditory perception; laboratory in sensory psychology; and seminars on perception, cognition, and language, and biological bases of behavior.

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