Eight-armed cognition: Octopus intelligence is distributed across its limbs
Most of an octopus’s 500 million neurons aren’t in its head: about 40–45 million in the central brain, 120–180 million in the optic lobes, and 300–350 million in the eight arms, making eight semi-autonomous processors that can sense, evaluate, and respond to stimuli within 100 milliseconds without routing signals to the brain, a distributed cognition architecture that challenges vertebrate brain-centric ideas of thinking and consciousness.