Professor of Neuroscience, Bennington College.
Title: “Awareness on the Horizon: Vision, Memory, and the Evolution of Consciousness.”
Abstract: Animal vision was arguably the most significant sensory innovation of the Cambrian period. Fossil evidence, together with comparative anatomical studies, suggest that the many varieties of eyes found in living invertebrates appeared within a span of less than 30 million years. I argue here that the ability to resolve objects at great distances was the key evolutionary innovation that precipitated the appearance of consciousness. The main rationale for this argument is the idea that resolving distant objects effectively opened an extended temporal window which allowed for both monitoring of salience (e.g., predators, prey) and making predictions long before any action is necessary. Monitoring a dynamic visual scene and making useful predications are necessarily predicated on an ongoing linkage between perception and memory. It has been argued elsewhere that primary consciousness arises from precisely this linkage (Edelman 1989). Allowing that single-compartment eyes with focusing lenses are a requirement for distance vision, one could plausibly argue that animals equipped with such eyes possess reentrant circuitry connecting perception and memory, and therefore experience conscious states.
The octopus eye has been cited as a beautiful example of evolutionary convergence because its design–consisting of a single vitreous compartment, focusing lens, seven ocular muscles, and retinal sheet–in many ways resembles that of the vertebrate eye. Moreover, the predatory capabilities of octopus and other coleoid cephalopods, as well as their sophisticated learning and memory faculties, strongly suggest the preeminence of vision among these animals’ various sensory systems. In light of the foregoing, I argue that the major attributes of coleoid cephalopod vision–from the various submodal properties that are most salient to the behaving animal to the electrophysiological signatures of those properties and their attendant neuroanatomical substrates–justify consideration of the coleoid cephalopod group as a test case for the possibility of consciousness in animals quite distant from the vertebrate line. More importantly, such a test case offers the promise of identifying universal neuroanatomical and neurophysiological properties of conscious states.
Bio: David Edelman is Professor of Neuroscience at Bennington College. His most recent research has focused on fundamental questions regarding, learning, memory, and visual perception in the octopus, as well as the evolution of higher brain function. He has explored octopus visual perception with the hope of providing a basis for investigating possible conscious states in the most complex of all invertebrates.