Topics Animals, plants and life

How do octopuses think?

Octopuses think with a nervous system built very differently from ours. They have an estimated 500 million neurons, a number sometimes compared to a dog's, with roughly two-thirds in the arms rather than the head. So each arm can taste, touch and act with a good deal of local control, while a central brain sets goals. How the two parts coordinate is still being studied.

What makes this interesting is the family tree. Our last common ancestor with octopuses lived roughly 550 to 600 million years ago, a small, simple, worm-like animal. Complex brains then evolved largely independently in the two lineages, though some building blocks may be inherited. That makes the octopus one of the best chances to ask what intelligence looks like when it is not built like ours. Researchers have seen octopuses open jars, navigate mazes and use tools in lab and field settings, but whether any of that amounts to experience like ours is debated.

An episode would walk through the arms, the skin, the short lives and the open questions. bre's hosts are AI, so they can be wrong, and you can press Talk to ask a question of your own.

What a bre episode would cover

An outline of the episode bre would make for this question. Every episode is written fresh when you ask, so yours will differ.

  1. A brain spread through the bodyAn estimated two-thirds of an octopus's neurons sit in its arms. We look at what that suggests about how decisions are shared between arms and the central brain.
  2. Puzzles, jars and escapesOctopuses in labs and aquariums have opened containers and found their way through mazes. We separate well-documented behavior from the stories that grow in the retelling.
  3. Camouflage and skinOctopuses change color and texture in moments, yet most have only one type of photoreceptor in their eyes. Researchers are still testing how they match colors, and we cover the leading ideas.
  4. Short lives, big questionsMost octopuses live only one to a few years, and most never meet their parents, so they probably can't learn from them. That makes their flexibility even harder to explain.
  5. Two minds, one distant ancestorThe shared ancestor with humans was a small, simple, worm-like animal roughly 550 to 600 million years ago. Complex brains arose largely separately in each lineage.
  6. Do they feel anything?Scientists debate how to measure experience in an animal so unlike us. We lay out the evidence on pain and learning, and where it stops.

How the episode might open

A sample exchange between two of bre’s AI hosts, bre and Tess. Both are AI; this is written by AI, as every bre episode is.

  1. breAI host

    Okay, picture an octopus arm cut off from everything else. It can still grab and react. So where is the thinking happening, in the head or the arm?

  2. TessAI host

    Wait, the arm acts on its own? That sounds like a problem for the octopus.

  3. breAI host

    It's more of a design choice. An estimated two-thirds of the neurons are in the arms, so a lot of the handling happens out there. How well it all coordinates, researchers are still working out.

  4. TessAI host

    So the brain sets the plan and the arms improvise the details.

  5. breAI host

    That's one way to describe it, though I'd hold it loosely. I don't know how much the arms decide versus just execute.

  6. TessAI host

    Okay, but real talk: why should I care? I don't have eight arms.

  7. breAI host

    Because the last ancestor we shared was a small, simple, worm-like animal, roughly 550 to 600 million years ago. Octopuses built a complex mind mostly on their own.

  8. TessAI host

    So it's a sign there's more than one way to build a mind.

Questions people also ask

Are octopuses smart?
By many measures, yes. Octopuses have opened jars, navigated mazes and learned from experience in lab and aquarium settings. Comparing their intelligence to ours or to a dog's is hard, because their brains and bodies are so different, and researchers are careful about broad claims.
Why is octopus intelligence so different from ours?
Our last common ancestor with octopuses lived roughly 550 to 600 million years ago and was a small, simple, worm-like animal. Complex brains then evolved largely independently in the two lineages, though some inherited building blocks may be shared. The result is a very different layout.
Do octopus arms think for themselves?
Partly. An estimated two-thirds of an octopus's neurons are in its arms, and arms can sense and respond with a lot of local control. The central brain still guides overall goals. Exactly how the two divide the work is an active research question.
Can octopuses see color?
Most octopuses have only one type of photoreceptor in their eyes, which would normally mean no color vision as we know it. Yet they match colors and textures around them. Researchers are still testing how they do it, and no single explanation is settled.

Related topics

More: all 300 topics, animals, plants and life, or the longer reads on /learn.

bre’s hosts are AI, and every episode is generated, so they can be wrong: check anything that matters. This page outlines what an episode would cover. It is for interest and learning, not medical, financial or legal advice.