Evolution of animal intelligence | Machines Like Us

Mano Singham has a interesting post up on a large scale review of animal intelligence studies.  

Animal intelligence is a fascinating topic and there have been many attempts at studying it.

Many of the individual studies look at one or other specific trait that we associate with intelligence in one species and the traits studied can differ from species to species, making general conclusions hard to arrive at. Ed Yong reports on a massive multinational study that looked across many species at one aspect of intelligence (self control) as demonstrated by two specific tasks. (You can read the paper on which his article is based here.)

via Evolution of animal intelligence | Machines Like Us.

What stuck out to me is this quote from the review.

They found a few surprises. For example, the animals’ scores correlated with the absolute but not relative sizes of their brains. In other words, it didn’t matter whether the animals’ brains were big for their size, but whether they were big, full-stop.

I’ve heard or read several times that intelligence was a factor of relative, not absolute brain size.  It’s starting to look like the data isn’t backing that up.  It reminds me how careful we have to be when accepting conventional wisdom, even scientific conventional wisdom, in areas where there’s not much conclusive evidence yet.

And of course, as Singham notes at the end of his post, there are lots of caveats and controversy with almost all of these studies, most likely starting with the way intelligence gets defined.

21 thoughts on “Evolution of animal intelligence | Machines Like Us

  1. Human Intelligence: the most clever of cognitive capacity in all the natural world for self-destructive and self-delusional decision making and goal seeking.


  2. Thanks ‘SAP’, always brings to mind corvids since learning how intelligent they are(it still amazes me). And given your recent post on alien intelligence this fairly leapt off the screen at me:

    ‘Crows could be the key to understanding alien intelligence’

    … that I found pretty interesting. I didn’t realize mammalian and avian brains were so vastly different. I also learned how to spell “leapt” – thanks!

    Liked by 1 person

    1. That is interesting. Thanks!

      Crows are probably the best counter-argument to intelligence being related to absolute brain size. The fact that they evolved intelligence also demonstrates that intelligence isn’t an evolutionary fluke. (Octopuses are another good example I think.) It seems like intelligence evolving in different evolutionary lines raises its probability substantially.

      Of course, it’s still possible that the level of intelligence humans have is a fluke. A number of factors came together for us: intelligence itself, social groups, physical dexterity, access to fire, etc. The other intelligent creatures, aside from other primates, only have subsets of these qualities. Crows, dolphins, and elephants have limited dexterity. Dolphins and octopuses have no access to fire. As far as I know, octopuses aren’t social creatures.

      It might be just the luck of the draw that we were the primates to develop symbolic thought and civilization spanning social groups before any of the others.

      Liked by 1 person

      1. Thanks again, I’ll have to do some reading on octopi(3 correct plural forms: octopuses, octopi, or octopodes per M-W 🙂 …

        Also, I meant to mention that Michael Graziano has some new stuff under ‘Papers and Reviews’ at:


        … a new paper, ‘Attributing awareness to oneself and to others’, Kelly et al 2014, and still In Press ‘Speculations on the evolution of awareness’ to be published in the Journal of Cognitive Neuroscience. The Abstract is available at:


        I finally ordered his ‘God Soul Mind Brain’ – still slogging my way through ‘Philosophy in the Flesh’ 🙂 it’s kind of a long-term project though.

        Liked by 1 person

        1. Thanks! I’ll check it out. After Tegmark and Ehrman, I took a break and am currently finishing James S A Corey’s space opera trilogy, ‘The Expanse’. Not quite sure what I’m going to read after that. I might finally swing back to ‘Blank Slate’, maybe.

          Liked by 1 person

      2. The octopus isn’t social, till you give it a dose of MDMA. Then it forgets its cloistered protective instincts, and moves to proximity of others of its ilk, out of captured curiosity and investigation, learning. If mankind has a warped function in the brain, or of various types, and which characterize its exceptional qualities, qua Man, who’s to say what mushrooms, fungi or chemically preserved nutrients (always a home brew) in the history of Ingestion and its consequences to evolution of the brain may ultimately prove convincing as to the etiology of praxis, creativity, adaptation, survival and thriving? Stoners, all.


        1. Wow BQ. You’re really looking back in the archives!

          “The octopus isn’t social, till you give it a dose of MDMA.”

          Would you happen to have any links on that change in octopus behavior? It implies they have some latent social circuitry in their nervous system. Which might be possible since they’re reported as being playful with humans. But I’m curious what in their evolutionary history might have led to it.


          1. Well, here may be the point of Punctuated Equilibrium, that the evolutionary imperative can be Jump Started under certain circumstances the survival mutations requisite to adaptation going forward, or expiration looking back. What if (speculation) the environment itself impels the PE, and its modus operandi is Ingestion…that times become crucial, desperate and liminal, thence a dietary change is determined, and likely an unpleasant one, being driven to scarcity, want and panting inertia?

            So, here’s my point: PE occurs only when extinction over time is proven inevitable for a species, as environmental viability collapses bit by bit around the organism, especially the local Group, being Social Animals we are talking about for the moment (albeit the First Principle would apply to all terrestrial organism (Gaia Theory?)). The localization of the Conscious Perception of extinction for the Group would set in motion a Communication on the available resources and viability of their exploitation in the short-term, the long-term appearing almost certainly terminal.

            What next? Well, PRESERVE FOOD SOURCES would be at the very top of priorities, along with GATHERING, being its precursor and benefactor.

            I’ll just end my little dalliance here on an historical note:

            How is it not coincident to my Theory that the Eleusian Mysteries celebrated by the Golden Age Greeks, who among themselves were as unlike as our many nations today, but shared a certain Mythos among them as a centralizing conceptual framework for their actions and aspirations?…HOW, I ask, is it not coincidence that their SHARED celebratory ‘drink’ together was a concoction of preserved grains, with honey and milk conjoined, and the additive Trick of Nature to contaminate these with elements, which working together, evoke evolutionary changes at the finest levels of Matter (DNA) and its consequent socialization as to thriving?

            Yep. Stoners, all.


          2. To this I’d also like to add the observation of Lemur’s in certain jungle terrain who, in their ‘spare’ time enjoy a little Frog Hunt, for the kind of frogs that human’s below (head hunters?…chuckle*) use to tip their arrows with mortal poisons, coincidently ‘hunting’ these same Lemurs. The observation that these Lemurs will hunt poison frogs, then take them to a nest or Safe Place to enjoy a little repast: Liking poison frogs, and getting as stoned as a Siberian Shaman on mushrooms gathered from Santa’s Summer Forest. Just saying:

            Stoners, all.

            Might I also add that, as a son raised among Dairy Farms that we all know better than to neglect feeding our Stock on fermented grains, leaves, herbs and what things we Gather from the Field. It’s good for the Digestion, where we harbor organism helpful to the full functioning of our nutritive health. And my point? Well…cows catch a buzz from fermented grains and grasses. They like it, better than they like mating…which is a fly-by-night excitement; whereas a good buzz after milking every day makes a cow happy enough to trot and dance and prance to the barn every morning and evening, if but the promise of a little Fermented repast is in the works.

            Then again, there’s the English version of America’s Tufted Titmouse…a bird which in England has acquired the taste for Milk, drawn from home delivery bottles sat on doorsteps long enough for ONE to figure-out how to get through the foil covering the Spout. But once learned, somehow affected the learning of other Titmouses in the region, certainly NOT by lessons learned by teaching, but by some alchemical transmutation of the DNA that instantly (spooky action at a distance) relayed to the Other half of the species’ a temporal equation, the exact Method of Survival for task at hand requisite in the moment, were these milk bottles the last, very last recourse of their adaptation and survival. Point being? Punctuated Equilibrium. Selah.*


          3. One can wonder, here, how Narrow may be the Gate through which the survival of the Species, ANY species, may depend; which when encountered, how few may enter there-through! Others trampling behind the one before, charging headlong at the Way Crossing of Extinction and Survival, one leading blindly over an Abyss in panic as the few escape into something new to come: Punctuated Equilibrium, whether some Lemmings, all betides till then/now and what comes next for them and all. Selah*


          4. And to Lumurs and Titmouse may be added Dolphins, who enjoy a little repast in catching Puffers, gumming them like rubber sports, but poisonous as vipers, passing the Puffers like a 70’s Rock Band passed a Dooby…each taking a munch, or a hit to pass the time. True Story.


          5. Radical Alterations of consciousness are the very ‘shift’ visionaries hope for, and will come, as they always have, from the Environment, where we move about and have our being.


  3. On the one hand, I’m not all that surprised. The idea that relative brain size has much to do with it has always seemed strange to me. If my brain were somehow transplanted into the body of an elephant, would I suddenly become stupid?

    On the other hand, humans (and also certain birds such as corvids) are smarter than you would predict from our brain sizes, so it’s not hard to see why the relative brain size idea was compelling.

    Unless I’m mistaken, larger animals tend to have more cells, not larger cells, generally. Intelligence is surely related to the complexity of the neural network implemented by the brain rather than volume, so if brain cells are approximately the same size there’s no reason why relative brain size should matter all that much.

    Thinking that the orthodox view had something to it, I assumed that in most non-human brains much of the brain is given over to processing nerve signals from all those cells. I assumed that large animals had more nerve endings than humans and so needed more brain power for processing this. This would explain why they have larger brains than humans but are not more intelligent, as it could be that the higher functions are represented by relatively small parts of the brain. On this hypothesis, we would expect brain size to loosely correlate to body size simply because of the demands of dealing with all those nerves. Deviations from the norm would therefore likely be explicable with reference to extra abilities on top of the norm, for example processing complex audio signals for echolocation in bats or higher mental function in humans.

    But even so we would still expect animals with larger brains to be more intelligent on average, simply because relative to the daily caloric intake of a large animal, the cost of running a sophisticated, intelligent brain is proportionately lower. An elephant wouldn’t even notice the caloric cost of running a human brain, whereas for a human it is quite costly indeed. It stands to reason that larger animals are more likely to evolve intelligent brains.

    So I guess humans and corvids are simply outliers. Small brains can be made more sophisticated by techniques such as increasing the surface area, thereby allowing more connections per neuron. Given sufficient selective pressure (e.g. sexual selection), I guess the caloric cost of our brains have been justified.

    Liked by 2 people

  4. The ‘brain’ of the elephant and man are as incommensurate as a square peg in a round hole, which makes your premise a non starter as being too obvious to argue otherwise. I stopped reading here.


    1. I’d bet when the truth be known, that the ‘brain’ has only as much in common with consciousness as its ability to recognize itself in Others, and from Experience over time lends every credence to the assertion that consciousness is a First Cause of learning and evolution over time for all surviving, thriving, and future-surviving species, on both the micro and macro levels, and whose chemistry is not distinct in time going back 500 million years from between one species’ “brain” and any other on the planet (in all fundamental respects to consciousness), at least in so far as mammals and certain cephalopods are concerned…chuckle* Other comparisons are across species are many and available to the historical record, methinks.


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