Could a sedentary organism develop intelligence, or even sentience?

Question

Similar to Could Plants Develop Sentience? but slightly more general: I'm not interested in plants in particular, but want a more general understanding of the effect of motion on intelligence and vice versa.

In general intelligent lifeforms on Earth, like hominids, cephalopods, and cetaceans, are highly mobile. Mobility and intelligence seem to be linked in our home ecosystem with the most mobile creatures having the largest brain-to-body mass ratios.

So the question I have is reasonably simple: is this a coincidence, a consequence, or a prerequisite for intelligent life? Could a sedentary creature, of any order, develop high levels of intelligence, possibly even sentience, or does intelligence require and/or beget movement?

For the sake of clarity my initial thought in asking this question was geared toward ambush predators like the snapping turtle only more sedentary in habit since most ambush predators I can think of move between kills and this theoretical lifeform either couldn't or wouldn't.

Answer 1

The only limitation of the development of intelligence is an evolutionary purpose. Every significant trait or feature present in a living organism is there because it helps that organism survive and reproduce. For a plant or other sessile creature to develop intelligence it must be able to use that intelligence in some way to improve its fitness. It might need intelligence to acquire food, avoid predators, or attract mates as a few simple examples.

In general non-mobile organisms have little use for intelligence. They can't move to find food, avoid predators, or mate. In general they lack most sensory inputs as well as motor functions, meaning that even if they were intelligent they wouldn't have effective ways of understanding the environment around them or of reacting to it even if they did. All that said, it's not inconceivable that there might be some task for which a sessile organism would require intelligence. Most likely this intelligence would need to develop along side appropriate sensory inputs (to give the intelligence something to think about) as well as some ability to react (to accomplish something once it decides to do so).

Answer 2

As mentioned by others,

Nothing evolves an adaptation just because. The reason there is a correlation between movement and intelligence is because movement requires understanding of your environment (must recognize that you cant run through a rock), if you are in a fixed position awareness doesn't really help you because you cant react to dodge incoming threats.

This begins to explain why there can be a correlation between intelligence and predation. One good way to be an effective mobile predator is you need to be able to recognize your prey and their patterns and plan a solution.

In all terrestrial cases intelligence has been evolved to react to the environment and to acquire food sources humans included.

To start answering your question:

your sedentary creature would need a reason to need intelligence other than to use motion to achieve a biological goal. Perhaps the weather is so erratic and violent that awareness and pattern recognition would need to be used to deploy protective measures on demand. Perhaps they develop a telepathic means of communication which aids them in reproduction being able to plan with eachother when is best to mate.

OR YOU COULD take the inverse of your scenario

Instead of a sedentary creature evolving intelligence, what about an intelligent creature de-evolving mobility. This isn't uncommon, there are plenty of birds which have lost the ability to fly because they found food sources without it (penguins and chickens).

You could even start to see such a trend in humans. We use to cover tens of miles daily and swing from trees. Now in many cases to be more productive requires tolerating a sedentary position for long periods (learning and working behind a desk). We have machines that can handle moving us A to B so it we don't really need our previous mobility. We very well could lose it. Your creature could be a parallel of this.

Answer 3

Okay, first off, it's important to say what no one here seems willing to say: no one knows squat about this. Everything anyone says or has said is the subject of intense debate and inflammatory argumentation.

What this means to a worldbuilder is simple: you don't have to explain it.

Any organism at all can have sentience, and no one on Earth can say anything about it. As far as planets with sentient life go, we have a sample size of one. There is simply zero sound science on the matter.

Expect argument on this!

Second, I'm looking around and I'm seeing a huge amount of poor, poor analysis of evolution, the kind of talk that leaves space for creationists to argue. If you see the words "evolutionary purpose" run screaming. The phrase is meaningless at best and harmfully misleading at worst.

Holy effing JC, I lose patience with this. Evolution has no purpose. Evolution's primary engine is randomness. Natural selection can narrow down the amount of successful organisms, but it doesn't create them or direct them.

I've got to say this again: evolution has no purpose. To say that this or that feature of an organism is constrained by "evolutionary purpose" is putting the cart before the horse, or if you will, the arthropod before the ganglia. The mechanism is simple: evolution happens by accident, natural selection narrows it down.

Look, here's a simple example: say there's a lush field full of life and flying creatures with all sorts of flowery ornamental plumage, as tends to happen when there aren't lots of predators around that can manage to catch birds. Then suddenly the field is buried in lava. What species of bird will survive?

Some subset of the birds that happened to be in the air at the time. None of those birds developed with the "evolutionary purpose" of surviving sudden outpourings of lava. Even more relevant, the color and structure of the plumage of the birds that survived had nothing to do with whether or not they survived the lava.

Those colors and plumage happened because the environment allowed the randomness of evolution to travel down all sorts of useless byways, because there was nothing around to stop it. Then, through nobody's virtue or intention, a bunch of them died off. Fast forward to today, and some people on various websites argue about the "evolutionary purpose" of this or that frilly crest on this or that bird. It's nonsense! It's pure folderol.

So these people talking about this or that environmental stimuli leading to the development of consciousness are talking out their bazoo. The rule is: evolution happens randomly to the degree an environment permits it.

So yes, a sedentary organism could develop sentience. It could be in the face of environmental pressures, or it could be just because it did, that's why, and there's nothing more to it.

Nobody likes this, because we don't like uncertainty, which is why you get a lot of authoritative-sounding talk like you'll see around. But the most irritating fact is that evolution seems like a system almost entirely designed to foil the kind of answers people like to give.

This isn't my thinking, by the way, I got all this from Stephen Jay Gould.

Expect argument on this!

P.S.: people should be cautious about using plants as an example of lack of sentience. It's not broadly known, but there is in fact a growing field called "plant neurobiology". It's highly controversial, but it's far from a settled argument, partly because certain plants have been shown to pass tests of sentience that it was previously assumed only animals could pass.

P.P.S: the other thing people who like to sound authoritative always leave out is sexual selection, a mechanism described by Darwin and almost entirely ignored in layman's arguments. Simply put, a hyperintelligent mollusk could evolve just because the female mollusks thought they were cute.

Answer 4

If we start from the assumption that the more an organ is used, the more it has to develop, it is easy to answer your question.

Sentience is the result of an high environmental pressure on the brain, that forced it to go beyond the simple model of instinctive reaction. The more an organism moves, the more it has to face a dynamic environment, and therefore also its brain has to be dynamic and able to "think out of the box".

As counterexample, just think of how many vegetables do you know which are sentient? Yes, there are plants which can react to external stimuli, but nothing even close to what we recognize as being sentient. In a sedentary set up a brain (and its massive energy demand) would simply be an evolutionary burden.

Answer 5

Intelligence is useful in deciding between choices. Taking away all options involving moving is a big limitation. But perhaps not fatal. You just need to give the creature a reason to make decisions based on complex input.

Prediction

Say the main food source is intermittent. The smart choice is to breed just before the source reappears. This only requires adjustable timing in reproduction and some meaningful sensory input to directly reward better predictors.

Or consider how much energy should be devoted to growth, storage or reproduction, there is some statistically optimal position for any set of conditions. The problem is how long does it take to find that sweet spot relative to the competition, what does it cost to be late, and how well can the spot be estimated from simple input.

In both cases on earth our immotiles like plants and shellfish do well by preprogrammed triggers, but here seasons are pretty predictable, to the point where it isn't worth paying for brains to try and beat the market. If the important events on your world were less predicable a more complex calculation would be useful. Maybe your creatures even need complicated communication so that non-local patterns can be used to predict local events.

Manipulation

Options expand very quickly with the competence of your manipulators. It is sometimes suggested a positive feedback between our manipulators and brains is a large part of the reason we are where we are. If they have a plausibly free manipulator and the senses to make use of it, it's not impossible they get a similar feedback.

Arms race

Say it lives by tricking some prey into its mouth. It needs to develop new tricks as fast as its prey figures them out. Both sides could benefit from better decision making.

Answer 6

Yes, possibly.

As has been pointed out, the development of sentience and intelligence does require some survival benefit (intelligence, at least, needs to be developed) and, generally, this requires the organism to have some kind of control over its environment, to make decisions and to be able to act upon them (which would normally require movement).

However, suppose that an organism had no real control over its environment, and that environment was increasingly volatile and unpredictable, but that the organism did have some control over its own biological functions: which direction to extend root systems; whether to grow height or foliage; when, and possibly even how, to reproduce; etcetera - essentially the ability to budget its energy and develop strategies to survive in an environment not as stable as most plants have.

Most plants have very simple responses that help them to grow and flourish: they sense heat and light; they use seasonal changes to drive their life cycles and these are all automatic, because automatic works in the majority of cases.

I think it quite feasible that an organism, though, on some other world with erratic seasons and weather, although being sedentary, might benefit considerably from the ability to make decisions on how best to utilise its resources, especially if the organism was carnivorous with a need to lure, trap and restrain prey.

Answer 7

It's an interesting idea. I think we have an extremely biased view on the whole subject of intelligence/consciousness, and even on our concept of what life is.

One possible path, using my biases as a basis, is that the genetic ancestors of said creator were mobile. At some point evolution favored the stationary.

Perhaps they live in an environment where movement is either:
too dangerous --those that move die
OR
the environment is so abundant in resources that moving around is pointless.

The plant/fungi route is also not too far fetched as recent research is showing us there is more going on there than we once thought.

Answer 8

In principle, sure. Lots of other people have suggested that it might have some evolutionary "reason" to become sentient - i.e., some advantage conferred by sentience that would allow it to do better than others. But! That's not the only way it could happen. Evolution doesn't move towards an optimized goal, it just throws away things that are harmful - it's possible that the reason your critters evolved sentience wasn't because it was useful to them, but because it wasn't harmful enough to make it worth getting rid of.

There's a phenomenon called pleiotropy: a single gene producing multiple apparently unrelated effects. For example, certain chickens have "frizzy" feathers, and the same gene causes them to have increased metabolism. Perhaps your critters evolved some useful trait that had sentience as a pleitropic side effect - a side effect that was at least not harmful enough to be worth sacrificing the useful trait in order to get rid of. It's unlikely that this would get you sentience right away - I doubt sentience is controlled by a single gene - but it could get the ball rolling.

There's also something called sexual selection, which is natural selection without the life-and-death part. The idea is that potential mates might focus on a particular trait that's unrelated to an individual's actual fitness, and use that to judge the quality of the mate. For example, this is likely the origin of the peacock's fancy tail. It's not unreasonable to expect it would be more common among species that were at least partially sentient, so that they had enough "society" to "decide" what was attractive. But if, early on, your critters "decided" intelligence was attractive, sexual selection might bootstrap them to full sentience.

One last idea (a little silly): in Vernor Vinge's "A Fire Upon the Deep", one particular species, the Riders, were sedentary - descended from something like a sea anemone. They didn't achieve much technology on their own, until in the distant past another species gave them machines that they could ride (hence the name) and use to do all the things most species use muscles for. There's no reason you couldn't have something similar - maybe a sedentary species that developed a glimmer of sentience, and then got helped along the way by someone smarter.

Answer 9

I attended a very interesting talk by Prof. Wolpert from Cambridge University once.

His talk started more or less with the following:

Why do we have a brain? It's a pretty fundamental question. Why have we, as a species, developed a brain, when there are so many organisms in our planet doing fine without it?

I argue that we have a brain for one reason, and one reason only: to produce adaptive and complex movements. And if you think about it, movement is the only way we have of affecting the world around us. Even if you think about communication, speech, sign language, writing, ..., they all require muscle contraction.

(He notes this isn't entirely true, and expands on it, but that's out of the scope of this answer)

He argues that perception and prediction bring no evolutionary advantages if not to improve movement. An example: there is no point in remembering places if it doesn't affect the way you move later in life.

Another point he mentions is that once you don't need movement, you may not even need a brain (see squirts eat their own brain when they fix themselves to rocks). -- although the scientific validity of this joke is questionable.

So if we believe in his hypothesis, which for me seemed pretty reasonable, then intelligence and motion are not a coincidence. Motion requires intelligence and there would be no point for a sedentary organism to develop intelligence.

Answer 10

Possibly a type of organism used as a ball in some form of sport could become sentient. This could make for an interesting sport as well.

Answer 11

Intelligent Design. Someone/something wanted to have things intelligent for any number of reasons and, with a good understanding of genetics, made some "things" to test a theory/give the creators something to interact with/create a curiosity item/build an early warning system for some danger/as pets/ as garden caretakers/as an outlet for their love, etc. The explorers may never find the creators just the intelligent sedentary life forms.

Answer 12

Considering evolution favors survival, but self awareness (the first part of intelligence) can also arise through other means, I think it is entirely possible. A bigger question is "Would we be aware it is alive?"

Theoretically a crystalline lifeform is possible, and it could develop intelligence. Being crystalline it does not need to move in ways that we can perceive to live, and so appears sessile to us. It eats thermal energy that it converts from its world's sun. It excretes the excess at night to the environment. It changes it's crystalline structure to affect its environment, using solar energy in ways we can't even imagine. It communicates using infrared light. It evolves over geological time spans.

We would have no idea it was alive, let alone sentient. With no awareness of it, and it likely having no awareness of us, there is no way for either of us to even say hello.

Now take this same lifeform billions of years later, and it has evolved faster thinking and the ability to "see" through it's surface. It has also learned to communicate using visible (to us) light, that is how it trains its pet insects. At this point, you have a sessile lifeform that is capable of communication with us, civilization as we understand it, even using other lifeforms as beasts of burden.
There you have your lifeform's history. Feel free to use any of that you like.

Answer 13

Best to look at ourselves as an example. Simplified, one of the main theories is that our brains grew to cope with the increased demand of social interaction. Remembering people's names, statuses, developing manners, social correctness, and basically surviving in a community and coming out top dog.

Some animals like baboons have a big red arse and the redder and more arsey it is the hotter that mate is, but humans are not quite the same - for us it's all about charm and social standing within a community, so we evolved to be able to manage that, the side effect being that our increased intelligence was useful for other things, and once you're on an evolutionary slope to improvement, you don't stop until it no longer benefits you. Keeping in mind that females will become more and more demanding of how funny, charming, popular etc. you will be we evolved into what we have today which is an incredibly nuanced system of finding a mate. You certainly can't just flash your bum anymore.

So yes, if they needed to become more intelligent, but more importantly, if they needed big brains for something else, even if it's remembering which mushrooms are safe to eat, there's a chance for evolution to push their intelligence in a sideways direction until they become sentient.

Answer 14

The main use of intelligence is prediction, for planning, for survival.

Motion is a relative concept.

In an environment where organism is sedentary but is surrounded by dynamic objects, interaction with which is required for the organism's survival, intelligence will develop.

The motion does not even have to be physical movement. As long as there is a change of signal with enough differentiation as to require prediction, planning, and dynamic choice-making - intelligence will become a factor of natural selection.

Answer 15

In our world, even the development of a nervous system seems to require mobility. The closest thing I can think of to a sedentary creature with a nervous system are shellfish. A clam's intellectual life is limited: Move up in the sand column. Move down. Filter water, clam up. But this is much more stimulating than the intellectual life of a carrot.

Moving up the evolutionary chain complex behaviour is more likely to arise in predators than in prey. As Speaker to Animals commented in one of the Ring World books, "How much intelligence does it take to sneak up on a leaf" This is a bit of an exaggeration, as smarts are needed to not be lunch. But generally predators have lower birth rates, higher survival rates, and longer lives than their prey. Coyotes are smarter than rabbits. Wolves are smarter than moose.

Another factor in this is the amount of time it takes to feed. Herbivores spend a large part of their day just munching. You have to pump a lot of leaves through a gut to get a reasonable number of calories.

Social behaviour seems to be a key feedback in developing more smarts. Pigeons are smarter than owls. (Training owls makes training cats look easy. Most of an owl's brain is hardwired image processing and hunting) Ravens (and corvids generally) are smarter than pigeons. But both pigeons and corvids exhibit social behaviours.

So to answer your question: To develop intelligence it needs to make multi-factor choices that are more difficult than can be handled by tropisms and instincts. Those choices have to affect the survival and reproductive success of the critter.

Answer 16

The answer to your question "Does intelligence require and/or beget movement" can be simply answered: "A form of intelligence requires/begets movement." We know this because humans are 'intelligent' and highly visually and movement-oriented. But to answer the more general "Do all forms of intelligence require or beget movement?" you'd have to do one of two things: either define intelligence strictly or get very broad in your thinking about how you get there.

It would be very easy, for instance, to define intelligence only in the human-like capacity. For a long time this has been a struggle in science: is x creature 'sentient'? How do you define that intelligence? Tool use? Language use? Ability to discern self (the so-called 'mirror test')? Ability to experiment? Ability to remember? For any given test there are some species that pass it and a lot that don't: chimps have a notion of self and crows pass down grudges between generations, some plants communicate by vibration and many animals use tools. Etc, etc.

It is also very easy to misunderstand evolution and how species get to where they are, recklessly ascribing words like, "Purpose" or "reason" to particular traits. There are twenty-three thousand genes in human genome. A water flea (a small water crustacean) has thirty-one thousand. There is a Japanese flower that has roughly fifty times what humans have in terms of genetic material. One thing that Dawkins points out in his 'Selfish Gene' book is that a lot of the time genes are carried not on the weight of their own evolutionary fitness, but that of the collective of genes in the organism in which they happen to exist. That is, a specific gene and the trait it expresses may have positive, negative, or neutral effect on the organism's health and in any of these cases have little to no effect on whether it survives: the weight of all those other genes and expressed traits is the overwhelmingly factor.

Combine this with the notion of inter-species gene flow, and we know that, in theory, the genes that create our as-yet-undefined intelligence could get to the target organism in any number of ways.

To properly phrase your question, you need to define what sort of 'intelligent' capability the species has, and you have to be pretty clear with this: saying something like, "Learn where things are in a space" means both rats and Roombas qualify. You need to phrase things in a manner that lets you distinguish between your intelligent species and ones who are 'non-intelligent'.

One way to do this is to consider what it applies it's intelligence towards. Humans have hyper-evolved visual cortexes: much of our 'intelligence' has to do with vision as a result. Eye-hand coordination is one aspect of this (and has to do with movement). Spatial recognition and awareness, object permanence, ability to recognize items, people, expressions all based on less-than-complete information all factors into this. Humans, in fact, probably 'fill in' most of the visual information they think they are getting (leading to 'the world is an illusion in our minds'). All of this is noteworthy because what it actually is is a pile of mechanical mechanisms we build on a particular sense that really only detect a narrow band of lightwaves.

You can imagine a similar set of hyper-evolved mechanisms that, say, detect subtle changes in PH. A 'digestive' intelligence that is able to factor out poisons and conserve rare nutrients. You can't cut out the concept of motion entirely, because things are still moving through a complex network of stomachs and intestines, as specially evolved as the rods, cones, neurons, synapses, glia and so on of a human visual cortex. But the organism itself may not be moving itself much, instead living in a river or ocean and simply processing everything as it came by - maybe even choosing how to excrete what it doesn't directly use to build up structures around it (golgoth sapians). Learning to count by filling stomachs instead of ticking fingers, etc. Communicating through the release of gases of different flavors. Cultivating farm animals by selectively maiming fish before depositing them in pens for later consumption. All of this is imaginable, and would lead to an intelligence of a highly different variety than humans.

So, to properly phrase the question, I'd encourage you to think first about how you want the sedentary species intelligence to express. Then, think about what biological processes that were hyper-evolved would lead to such an expression. And then work back from there, knowing that the genes which caused this expression could come from anywhere: from food it ate, air it breathed that contained pollen. The genes could have come from another species with proto- or full-blown intelligence whose genes were carried in spores and later captured and repurposed. The intelligence could be entirely accidental, having arisen by chance and been lucky enough to be in an organism that was very environmentally viable with or without intelligence. But embrace that evolution is a billion trillion balls bouncing around a sphere and sometimes some of them fall through the hoop of 'intelligence' or 'has opposable thumbs', and none of them ended up there for a 'reason'.