Consciousness of octopuses—on their own terms

Abstract

Because cephalopods are so different from the vertebrate lineage, their possible consciousness must be assessed on the basis of their heritage and abilities. Cephalopods have evolved in water, a denser medium than air, and their perception is adapted to it. They have inherited the molluscan mantle cavity and hydrostatic muscle type, which has led to a more distributed motor control system despite a centralized brain, and have evolved a completely novel skin display system. Using these abilities, octopuses can form concepts, plan for the future, generate a cognitive map, and self-monitor for apparent pain and manipulate communication. Most cephalopods use the skin display system fairly automatically to deceive potential predators, although cuttlefish and squid also communicate with conspecifics. They do not appear to have the social sophistication to form a Theory of Mind when using it, but some squid can divorce the skin output from its motivational background sufficiently to produce two separately motivated displays in different directions at the same time. Thus, the cephalopods do appear to be moving towards consciousness, but on their own terms rather than our vertebrate terms.