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This brings up a question for me. Does brain size always correlate to intelligence? I see a dolphin brain that looks very human and I think that it does, but th
by xeromal 4y ago
This brings up a question for me. Does brain size always correlate to intelligence? I see a dolphin brain that looks very human and I think that it does, but then I see how smart crows are and I'd honestly say that they're smarter than my dog in most ways.
- bpodgursky 4y agoWithin generally similar animals, brain size is correlated with intelligence. Across different branches of the tree, it's harder to compare. Bigger bird brains ~= smarter birds. Bigger dog brains ~= smarter dogs. But you can't directly compare dogs and birds in that way.
- kanzure 4y agoIt's the absolute number of cortical neurons, not the size of the brain. "Brains matter, bodies maybe not: the case for examining neuron numbers irrespective of body size" https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2011.05976.x https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-... "No relative expansion of the number of prefrontal neurons in primate and human evolution" https://www.pnas.org/doi/full/10.1073/pnas.1610178113 https://www.pnas.org/doi/full/10.1073/pnas.1610178113 "The human brain in numbers: A linearly scaled-up primate brain" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776484/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776484/ "The elephant brain in numbers" https://www.frontiersin.org/articles/10.3389/fnana.2014.00046/full https://www.frontiersin.org/articles/10.3389/fnana.2014.0004...
- bpodgursky 4y agoYeah, I don't think that's in contrast to what I said. Neural architectures are very similar between closely related species, and differ wildly between birds and whales.
- f6v 4y agoI’d rather ask about body/brain ratio and % energy consumed by a brain.
- hutzlibu 4y ago"Does brain size always correlate to intelligence?" Not really, otherwise whales and elephants would be way smarter, than us. Well, some people say, they are, but it does not show in our intelligence tests. And birds brains evolved differently than those of mammals, so maybe they are more efficient with their relative small brain? Because yeah, they are definitely smarter than dogs, who have a bigger brain.
- Zamicol 4y agoMaybe whales are "smarter" than us. How can we empirically test whale intelligence? Their technological abilities are obviously inferior, but I wouldn't be surprised if they were surprisingly intelligent in other ways. I'm trumpet dumb, that doesn't mean I'm not "overall smarter" or "niche smarter" than some people who play trumpet.
- prox 4y ago“For instance, on the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much—the wheel, New York, wars and so on—whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man—for precisely the same reasons.” - Douglas Adams
- xen2xen1 4y agoThis quote is always in the back of my head anytime brain size or intelligence is discussed, and is especially when dolphins are mentioned. And, he has a point.
- prox 4y agoAs I reflect on the quote more and more, I believe the dolphins have the right idea.
- hutzlibu 4y agoBut apparently the dolphins in hitchhikers guide to the galaxy did a bit more, than just having a good time in the water - because unlike the humans, they managed to find a way to leave the earth, when it was destroyed. (Book 4) And this is not further explained in the book, but it likely sounds like technology. And when you want to have and use technology, you have to do more than just splashing around..
- cjbgkagh 4y agoBirds have a higher neuron density. Each neuron is a mini Turing machine running on DNA instructions so they could also have better instinctual software.
- dcow 4y agoNot sure if that analogy holds exactly. Neurons don't “compute”, they simply emit a signal that depends on how “saturated” they currently are, right?
- deleted 4y ago[deleted]
- cjbgkagh 4y agoFeel free to research it. The ‘saturated’ analogy is overly simplistic and elides the incredible complexity of what’s actually going on.
- dcow 4y agoBut neurons certainly aren’t mini Turing machines, either? Happy to inform myself more if you can point me in the right direction.
- svnt 4y agoCells perform a staggering number of parallel computations. Neurons are cells, and perform these same calculations and more in addition to emitting spikes. Spikes, rather than being the major form of computation, appear instead to be a means of maintaining synchronization.
- dcow 4y agoI quite honestly did not think of it this way. But it makes some sense. I always thought cells perform, for lack of a better term, self-maintenance operations independently from their macro function (the receiving and emitting of spikes, in this case). I did not think of the internal operations of a cell being connected to the macro function in any sophisticated or meaningful way. I would love to inform myself better on this topic since it is not by area of expertise, and I have an admittedly cursory understanding.
- gonehome 4y agoIt’s an interesting question and the answer is also pretty interesting: https://obscuredinosaurfacts.com/post/2022/11/30/bird-brains.html https://obscuredinosaurfacts.com/post/2022/11/30/bird-brains... There are a few factors and that post gives a nice overview.
- xeromal 4y agoThanks! I've always been curious. Just opened this up.
- kick_in_the_dor 4y agoI haven't yet read the main article at that link, but its opening links to another long blogpost on whatbuywhy.com about the human brain and it's fascinating! Highly recommended: https://waitbutwhy.com/2017/04/neuralink.html https://waitbutwhy.com/2017/04/neuralink.html
- User23 4y agoDogs have been bred for docility not intelligence. Their wild cousins, wolves, are considerably more intelligent, they’re just prone to get bored and engage in undesirable behaviors. I’m told that it’s very easy to teach a tame wolf tricks, but they quickly lose interest in obviously pointless activities, especially as they mature.
- taneq 4y agoSo wolves have ADHD, right. :P
- svnt 4y agoIf you think about it, ADHD behaviors would likely be much more adaptive in the wild than non-ADHD. It is possible ADHD stems from genetic regression.
- tigerlily 4y agoWhat are you trying to say?
- svnt 4y agoIt is possible that the selective processes that led to ”modern” brains are essentially a process of self-domestication, and certain “diagnoses” are just reflections of diversity in that process. If society collapsed I think it would be more beneficial to be ADHD than not.
- emmelaich 4y agoI've seen studies relating hyperactivity to Neanderthal and older genes. They persist because not enough time has passed to mutate them out.
- taneq 4y agoNot them but just guessing... that most ADHD traits are only 'disordered' if you expect humans to be able to sit still, shut up, and focus exclusively on what you tell them to focus on for 8 hours a day?
- bmitc 4y agoDolphins and orcas specifically actually have higher density of folds in their brains than human brains in addition to being big. The book Deep Thinkers: Inside the Minds of Whales, Dolphins, and Porpoises is quite good.
- sieste 4y agoNot exactly an answer to your question, but a few studies report a weak positive correlation (around .3) between head size and IQ in humans. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=correlation+head+size+iq&btnG= https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=corr...
- svnt 4y agoBut several in your search, including the twin study, report no correlation, and others report correlation only within race and sex groups.
- clnq 4y agoIf there's a weak correlation in a population, finding no correlation in some subpopulations and a stronger correlation in others is expected. For example, a very weak correlation between GPA and job performance exists. In some disciplines, like law, the correlation is strong. In other fields, like extreme medicine, there is no correlation.
- astrange 4y agoAre there studies on GPAs of extreme medics? …Why? (And how much education did they have? The field includes people who have and haven't gone to medical school, I assume.)
- clnq 4y agoNo, this was meant to be an intuitive example of weak correlation. It could have been about a correlation between the redness of a fruit and its sweetness. For the entire population of fruit, it is weakly correlated. For some apples, it is strongly correlated. And for tomatoes, there is no correlation. Extreme medicine, which includes field, mountain, and battlefield medicine, is a specialization of general medicine. You can study it as a part of various programs. I studied it as a specialization in a general practitioner's MSc program in Central Europe. Depending on the region, it is probably possible to specialize in extreme medicine as a nurse or an EMT. There was a wide range of GPAs in that program because success was measured by a narrow range of criteria that did not include things usually considered "academic aptitude" - mainly the ability to follow resuscitation algorithms in simulations precisely. Some of the things we were scored by automatically were time to ECG, time to defibrillation, correct callouts to the team, intubation depth and time, and chest compression depth and rate. And failing to execute a particular algorithm meant immediate failure. Every other imperfection immediately meant a reduced score, and scoring was entirely metric-based in simulators, not open to human interpretation. Scoring just 45% of the possible grade on tests was considered excellent. You had to demonstrate very high competency to pass. Mediocre knowledge of algorithms or skills in resuscitation was unacceptable because that would severely worsen the outcomes of actual patients. If you either cared about your GPA or were primarily motivated by your GPA at school or university, it was clear that this would be a very difficult specialization for you. It was more for people who excelled in algorithm following, composure under stress, and perseverance; and those who wanted a high skill ceiling.
- taneq 4y agoBirds are smarter per unit of brain matter than mammals and it baffles me why more people aren't intrigued by this.
- catskul2 4y agoWhich people are not intrigued by this?
- perth 4y agoI’ve read there’s decent correlation on a few scientific journals on Google scholar. Namely, that while head size doesn’t guarantee intelligence, if you are predisposed to intelligence you can’t be as smart as someone else who is predisposed to intelligence but has a larger head. See: the spatial packing problem in human brains
- joe__f 4y agoDon't you want to look for something like brain/body mass ratio and see how that correlates with intelligence?
- coyotespike 4y agoYes to a first approximation this is a good heuristic! https://en.wikipedia.org/wiki/Brain%E2%80%93body_mass_ratio https://en.wikipedia.org/wiki/Brain%E2%80%93body_mass_ratio https://en.wikipedia.org/wiki/Encephalization_quotient https://en.wikipedia.org/wiki/Encephalization_quotient
- svnt 4y agoNo because the structure and function of the organ is at least as important as the size. Size (or rather some bound of neuron/glial count + complexity) is more in the necessary-but-not-sufficient category. Secondly the question is not well-posed enough to answer accurately. What is intelligence, in this case? The cytoarchitecture of brain parcels/regions varies significantly. If you have a giant cerebellum you are not going to seem very smart to us, but you may have a very large brain. At the other end, people have lived normal (if perhaps internally simpler) lives with tiny fractions of a typical neocortex. [0] 0 : https://www.sciencealert.com/a-man-who-lives-without-90-of-his-brain-is-challenging-our-understanding-of-consciousness https://www.sciencealert.com/a-man-who-lives-without-90-of-h...
- LarryMullins 4y agoLarger animals tend to have larger brains than smaller animals. If you divide the actual brain size of an animal by the size of brain an average animal that size would have, you get the "encephalization quotient". If you rank some common animals by encephalization quotient, most of the resulting order probably isn't surprising to many people: Human: 7.4 - 7.8 Dolphins: 5.3 Chimps: 2.2 - 2.5 Ravens: 2.49 Dog: 1.2 Cat: 1.0 Some of them are surprising: Mouse: 0.5 Rat: 0.4 Rats are certainly smarter than mice, so this analysis is obviously limited. Still, it seems to generally give expected results. https://en.wikipedia.org/wiki/Encephalization_quotient https://en.wikipedia.org/wiki/Encephalization_quotient
- svnt 4y agoVery familiar with EQ. If you read the wiki article you cited, most of it is references to people disputing the relevance of EQ. eg 0 Currently the best predictor for intelligence across all animals is [forebrain]neuron count.[[5]](https://en.m.wikipedia.org/wiki/Encephalization_quotient#cite_note-houzel2017-5 https://en.m.wikipedia.org/wiki/Encephalization_quotient#cit...) 1 In a meta-analysis, Deaner et al. (2007) tested ABS, cortex size, cortex-to-brain ratio, EQ, and corrected relative brain size (cRBS) against global cognitive capacities. They have found that, after normalization, only ABS and neocortex size showed significant correlation to cognitive abilities. 2 The notion that encephalization quotient corresponds to intelligence has been disputed by Roth and Dicke (2012). They consider the absolute [number of cortical neurons] and [neural connections]as better correlates of cognitive ability.[[16]](https://en.m.wikipedia.org/wiki/Encephalization_quotient#cite_note-16 https://en.m.wikipedia.org/wiki/Encephalization_quotient#cit...)
- cscurmudgeon 4y agoOne analogy is computers: bigger is not more powerful, structure matters more.
- polski-g 4y agoWithin a species, yes. There is a 0.41 correlation between brain size and intelligence in humans, for example.
- JamesBarney 4y agoBirds have evolved to have very space efficient neurons, due to their weight constraints.
- suzzer99 4y agoInterestingly, the biggest bird of all, the ostrich, might also be the dumbest. Or at least ostriches are in the conversation with pigeons and turkeys.
- mtlmtlmtlmtl 4y agoProbably this is because the ostrich doesn't need to be as intelligent. No flight, big clumsy beak etc. And they can avoid predation just by being huge and kicking really hard. City birds like crows and pigeons have puzzles they can play with like getting food out of garbage bins and so on. City birds tend to be more intelligent than countryside birds, even within the same species. I always felt like cats are actually smarter than dogs in a lot of ways. Dogs have a lot of their brain power dedicated to manipulating and communicating with humans, as well as trainability. But untrained dogs just seem kinda stupid and helpless to me whereas cats can learn to be almost completely independent with next to no training. Dogs are evolved from pack animals of course which explains a lot of this. I do love dogs though, just to be clear.
- Breadmaker 4y agohttp://www.xenology.info/Xeno/3.3.htm http://www.xenology.info/Xeno/3.3.htm some correlation atleast.
- terminal_d 4y agohttps://pumpkinperson.com/2019/01/04/what-is-the-correlation-between-iq-and-brain-size-and-how-causal-is-it/ https://pumpkinperson.com/2019/01/04/what-is-the-correlation... https://pumpkinperson.com/2019/08/15/increasing-u-s-head-size-1946-to-2012/ https://pumpkinperson.com/2019/08/15/increasing-u-s-head-siz... Last link has a formula to calculate cranial volume. Animal intelligence is vastly underplayed. Ants seem to be a very intelligent creature but they're little more than part of nature to us. We're similarly adapted to our environment, and those animals are adapted to our patterns and mentation by virtue of millennia of close contact / purposeful genetic pushes (eg, dogs)
- TheRealNGenius 4y ago[dead]
- buywarbonds 4y agoNo. A tiger is not 10x smarter than a house cat.
- feet 4y agoThat assumes the correlation would be linear
- stared 4y agoIt is the easiest way to add more brainpower within the same architecture. Think: adding more RAM or another GPU. Different architectures, like in tech, have different specs. More is not always better, as a bigger brain is costly, and the price is only sometimes justified - as with buying more GPUs.
- hinkley 4y agoDinosaurs had their chance and they lost, but I'm slightly terrified of the idea of a crow scaled up to the size of a chimpanzee, and I actually like corvids (though not as much as some). There are raptors roughly that size, so it's not impossible, unlike scaling an ant to the size of a crow, which would only give you a paperweight made out of chitin. They clearly have a different 'instructions per cycle' ratio from mammal brains.
- stoat_meniscus 4y agoRISC? Reduced instruction set corvidae
- Rury 4y agoBrain size has more to do with body size than anything. Most of your brain functions as a motor control and sensory processing center. To willfully move muscle in your body, requires brain power. This is why after a stroke, and a part of your brain dies, you can lose both the ability to move sections of your body, along with feeling anything in those sections. As so, larger animals have bigger bodies, and hence typically have bigger brains in order to handle/control their larger bodies.
- agumonkey 4y agoI'd be extremely interested, because good biological foundation for intelligence doesn't necessary leads to advanced thinking. Size + internal structure + context.