What would be the psychological effects of a sentient creature having its central nervous system distributed throughout its entire central body? How would they think differently than humans? This seems like there could be some very interesting consequences that would stem from it, but I don't know what they would be. The only thought I have is faster reflexes but slower complex problem-solving.

I'm actually using this for a game of Pokemon Tabletop United for the tentacool/tentacruel line. Other psychological changes that I'm using are that they primarily rely on their senses of smell and touch, while vision is used almost exclusively for locating opponents in battle and communication since they communicate by flashing light from the orbs on their bodies. They also are primarily ambush predators.

I'm also open to other suggestions about psychological traits that could show up in them, but the above question is primarily what I'm looking for.

  • $\begingroup$ I have a sapient species like this in a story, but I linked up the nerves with biological fiber optics to speed communication so the different parts could "talk" to each other rapidly. $\endgroup$
    – DWKraus
    Jun 9, 2020 at 21:07
  • $\begingroup$ This depends a lot on the creatures body plan, if you tried to do it with a human it would require a lot more neurons and thus calories, neurons are calorie hogs. It also would result is some very slow thinking speeds. $\endgroup$
    – John
    Jun 10, 2020 at 12:35
  • 2
    $\begingroup$ John: Sort of a jellyfish / octopus like body plan. $\endgroup$ Jun 10, 2020 at 15:11
  • $\begingroup$ Science fiction writer Robert Heinlein envisioned creatures with uncentralized nervous systems--and a shot to the head wouldn't necessarily kill them. $\endgroup$ Jun 16, 2020 at 5:30

4 Answers 4


Well the best real life comparisons we have to a less centralized nervous system are cephalopods (focusing on the octopus) and arthropods (other animals also have less centralized nerve distribution, like worms and jellyfish, but I don't find them good examples for a sentient creature).

So let's start with what we know about these creatures. Octopuses might be the best arrangement according to what I understood you want. They do have a centralized brain, but about 3/5 to 2/3 of all of their nerves are located in their arms. This, combined with the fact that each arm has hundreds of sucker pads capable of taste and smell, as well as their different "wiring" (octopus react to stimuli via behavioral patterns while we react via mechanical patterns), we have a creature which works normally as a single organism, with 8 arms that are basically capable of self-decision (severed tentacles have been shown to capture food and try to take it to where the mouth was). By this arrangement, we'd likely see a scenario in which the person doesn't need as big of a skull, but apparently will be capable of functioning essentially like a normal human, except this person might normally move around a bit more, letting their arms feel around for food and then shoving it into their mouths while they're talking to you as if nothing was happening, or reach their limbs out to feel your face should their owner not issue a command to stop and stand still.

Regarding faster reflexes, you'd e more or less correct, as the person's limbs will act in a way similar to involuntary reflexes, taking decision by themselves. you'll likely pull your arm faster from something hot, and you'll be able to grab things faster, but I other than that, I see no major differences. Your brain will take the same time to process images or sounds, and you won't run any faster than you already do.

Now the arthropod nervous system: in addition to a main brain, arthropods have several ganglia, dividing the nervous functions among these. This is basically why many insects can survive long periods without a head, as they basically have several secondary brains, which were responsible for keeping the body running, still intact. Crudely saying it would work exactly the same for us, in this arrangement, I don't see an increase in reactive response, as you "basically" just took certain bits of your normal brain and relocated them to your spine, but, with proper medical assistance (gotta stop the bleeding), you might be able to outlast your own head.

So essentially I'd say you'd likely be more interested in the octopus version of a less centralized nervous system. Your limbs might react faster to stimuli and things like repeated stepping or moving your hands around will likely be much more common and even seen as normal, but otherwise I'd say you won't be that different from a normal person

Octopuses as they are can solve puzzles, use tools, are naturally curious and ingenious, get bored easily, seem to be able to hold grudges, and can remember people's faces and taste (I know what I typed), so maybe your sentient creature might be more curious and exploring, as well as getting bored more easily, but that might be more from your personal decision than a trait inherent to the way their nerves are distributed throughout their bodies.

  • 1
    $\begingroup$ "can remember people's faces and taste (I know what I typed)" possibly the best and also most disturbing detail I've read on this website. $\endgroup$ Jun 13, 2020 at 0:54

enter image description here

Ask this guy about their psychology, I don't know any doctor or psychiatrists who interrogated an octopus about their mental health.

Although cephalopod intelligence has been highly studied across the years, we do not know how to communicate with other animals therefore we can not assess their state of psychology. The only thing we know about their psyche is that like every other intelligent animal on earth, when forced into isolation they become more desperate and start socializing with other species. Just like humans with cats.


There would be no difference.

Psychology is about consciousness, and as long as the being has only one identity, it's not relevant where it is physically located. If a nervous system component is controlling some organ or subsystem, it does so without being conscious itself, and possibly without allowing conscious control.

Humans have examples for it themselves:

Our gastrointestinal tract is controlled by the enteric nervous system (ENS), which is so much autonomous that it is even colloquially called "second brain".
There is no psychology of the colon. We can not even consciously control the muscles that produce the movements to transport the contents of the colon.

Also, our central nervous system is distributed, our brain consists of two parts that are connected by bundle of nerves. But out psychology is only about one person, even while we know the physical representation is separated in two locations. It's possible that we can be conscious in multiple locations, but only one at a time - that would not change anything.


They would make more snap decisions and be less intelligent overall.

Your brain is made up out of hundreds of thousands of neurons all connected to each other. Especially early in your life but also later on the usage of these neurons will determine what happens to them. Barely used connections are cut, often used connections are accelerated and rewired to reduce the amount of neurons that process the information to the proper answer for efficiencies sake. This creates a unique brain, so unique that it defines everything we are. Even if I somehow swapped all my memories and preferences with yours, I would now have your brain paths to deal with and I would imediately get your character as that is simply how your brain functions and is wired.

Now extrapolate this to your beings. Even if they have the exact same amount of neurons, those neurons are further apart. The information of your balance organ now needs to be processed and instead of sending it to the cerebellum next door it has to send the same message a dozen time to each seperate neuron cluster operating an arm, leg, spine, hip, finger or whatever else. This increases the signal density needlessly and reduces the amount of signals you can send around, not even mentioning the extra time needed for this message to reach all extremities and be processed individually by each neuron cluster rather than just by one cerebellum cluster that does the operation once with less total neurons and then uses this for all extremities.

This counts for everything. More total processing power is required and less time is available as it already took longer to process. This means that the neuron clusters have to shortcut their way to the answer, and we already know this is possible during flight or fight responses. In emergency situations your brain stops taking as much time to process everything to save your life, but it also means your brain will make mistakes. People will run back the way they came as their brain knows that route, all those green "escape" signs stop having a meaning and take much longer to process. It can take minutes or even hours before your brain tells you "hey that sign over there is actually what I was looking for". And this type of short-cirquiting will be exactly what your beings will be doing more or less depending on how decentralized they are. Quick to respond, good choices in a natural environment but the moment they are out of their depth and have to strategize or anything they are screwed.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .