Cephalopod Behavior and Neurobiology: An Alternative Model for Intelligence
University of Washington, USA
David H. Gire
University of Washington, USA
Understanding the fundamental constraints that shape the diversity of intelligent life on Earth will allow us to anticipate the possible forms that extraterrestrial intelligence might take. Since the nervous system first evolved, it has diverged and radiated into countless forms. Most familiar to us is the centralized nervous system of the vertebrates. Although highly morphologically conserved, this nervous system model has developed within a large range of complexity. Among the most sophisticated and cognitively complex of these forms includes that of the canids, corvids, cetaceans, and hominids.
At the other end of this divergence cephalopods evolved for hundreds of millions of years in parallel toward cognitive complexity of their own. Specifically, octopuses have demonstrated a capacity for observational learning, exploration, play, spatial learning, and problem solving. They have also shown individual variation to the extent of personality and signs of consciousness.
What has evolution done with the ancestral proto-nervous system to produce such behavioral complexity without being confined to the centralized nervous system of the vertebrates? The nervous system of the octopus is extensively diffuse, and collectively, their eight arms bear more neurons than their central nervous system. Each arm is consequently highly autonomous, requiring inhibitory innervation from the central nervous system to monitor its behavior. With this configuration octopuses have outsourced much of their cognition toward their peripheral nervous system. Sensory information is therefore not integrated collectively but as discrete components, making octopuses resemble more closely a swarm intelligence than they do centralized models of intelligence. While their entire psychology has been evolving separately from our own since our phyla speciated 670 million years ago8, their cognitive capacity has come to rival that of even our most intelligent cousins. They effectively serve as a model for an alternative intelligence and hold astrobiological significance, providing insight into an alternative evolution of intelligence and suggesting possible forms extraterrestrial intelligence could take. In fact, the closest we can currently come to studying an alien intelligence is to study the octopus.
Through the study of the behavior and neurobiology of octopuses and other cephalopods, we can begin to understand the diversity that evolution could make of extraterrestrial life and intelligence. Simultaneously, those fundamental characteristics that cephalopods share with more well-known forms of intelligence, the globally conserved traits among all known forms of intelligence, will provide a general basis for what we can expect from an extraterrestrial intelligence, as well as perspective on our reflexive anthropocentric assessments such as their level of benevolence or aggression.
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