Anyone who has been in close proximity to an octopus will frequently describe the moment when the creature turns to face you and something happens. Not precisely recognition. Akin to an appraisal. It was written about by Sy Montgomery. Years ago, Eric Dorfman, who kept one in a tank, observed that his octopus appeared to divide people into two groups: the human who brought dinner and everyone else. It seems endearing until you consider the implications. A social model of the humans standing outside its glass was being silently run by a creature that was built on an entirely different evolutionary branch and had no common neural architecture.
The number of neurons in octopuses is approximately 500 million, which is comparable to that of a dog. But the count isn’t the surprise. The distribution is the issue. The arms contain about two-thirds of those neurons, each of which functions with a degree of independence that would be unsettling if it weren’t so graceful. It will continue to grasp and react for a while on its own if its arm is severed, which is an unfortunate result in the wild. The oesophagus is encircled by a doughnut-shaped ring called the central brain, which does not micromanage. It works together. Even though that isn’t how “thinking” is supposed to function, here we are.
| Key Information | Details |
|---|---|
| Subject | Cephalopod cognition and the study of non-human intelligence |
| Primary Species Discussed | Octopus vulgaris (common octopus) |
| Neuron Count | Approximately 500 million (comparable to a small dog) |
| Neural Distribution | Roughly two-thirds located in the eight arms |
| Genome Complexity | Around 33,000 protein-coding genes |
| Evolutionary Divergence | Last common ancestor with humans lived over 500 million years ago |
| Notable Behaviors | Tool use, maze-solving, camouflage, self-control tests |
| Class | Cephalopoda (includes squid and cuttlefish) |
| Consciousness Status | Recognized in the Cambridge Declaration on Consciousness (2012) |
| Key Books on the Topic | Other Minds (Godfrey-Smith), The Soul of an Octopus (Montgomery) |
| Physical Anatomy | Three hearts, blue blood, doughnut-shaped brain around the oesophagus |
| Cultural Moment | Paul the Octopus, 2010 FIFA World Cup predictions |
The thing that keeps pulling at me is the evolutionary distance. Over 500 million years ago, a simple worm-like creature was the last common ancestor of humans and octopuses. Chimpanzees, crows, dolphins, elephants, and every other animal that is commonly referred to as intelligent sits much closer to us on the tree. The octopus is a completely different experiment. It’s possible that intelligence, whatever the term actually means, is more of a collection of solutions that evolution keeps stumbling toward from various angles than it is a single destination. The door was unexpectedly taken by the octopus.
It’s difficult to ignore what it does with that architecture. By any reasonable definition, the veined octopus uses tools when it gathers coconut shell halves and carries them across the seafloor for use as armor later. In a 2021 study, cuttlefish were able to pass a marshmallow test by holding out for a better snack. An octopus solves a jar in a clip from Oregon Public Broadcasting that has gone viral online. As the video progresses, the researchers’ commentary becomes quieter. In real time, you can hear them determining how much credit to give the animal.
The AI community has taken notice. An increasing number of researchers are beginning to view the octopus as a challenge to their own presumptions, including some who have dedicated their careers to attempting to replicate human cognition in silicon. Gary Marcus is adamant that machines learn in the same manner as kids. However, why that default? The blueprint isn’t unique if decentralized problem-solving, distributed intelligence, and skin-based sensory reasoning all developed on Earth without a human-like cortex. Perhaps it never was.
Beneath all of this is a more subdued ethical current. The fact that the EU and a number of US states have started to extend animal welfare protections to cephalopods gives you an idea of the direction that science is taking. It’s difficult not to feel as though we’ve been asking the wrong question for a very long time as we watch this develop. Not if octopuses have human-like thought processes. Whether thinking—as we have defined it—was ever the limit in the first place.
