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Scientists re-evaluating relative brain size and mammalian intelligence
- sitkack 6y agoGiven that our higher cognitive powers come from a millimeters thick section the size of an unwrapped golf ball, brain volume doesn't mean much, and brain volume vs body size means even less. Human assumptions about intelligence are debunked by facts.
- logicslave 6y agoI would argue its rather that the facts are too hard for society to handle. A neural network that predicts IQ from physiology/outwardly visible characteristics is certainly possible. Phenotypes exist and display specific behavioral and thought process traits. But to recognize it would be like staring into the sun
- AussieWog93 6y agoI've read some of your other comments and have the strong impression you're trying to make a comment tying IQ to race without actually saying the word outright. I'm not going to say that you're morally reprehensible, but I do recommend reading about the Flynn effect. The variance in IQ between modern whites and whites 100 years ago is significantly higher than any measurable difference between whites and blacks today. In addition to this, the IQ of blacks is rising at a faster rate than the IQ of whites, and seems to be approaching convergence. Looking at changes over time, it seems that average IQ in large population groups is mostly a function of culture rather than genetics.
- logicslave 6y agoIt's more so that I am in awe of the widespread brainwashing that I see in society. Head into a college library, maybe into the biology or genetics section, crack a book from twenty years ago thats not well known. Read dissertations, there are bodies of knowledge inside universities and medical professions that aren't exposed to the public.
- ggm 6y agoBodies of knowledge about what? I agree with your respondant: your answers obscurity tends to imply you're avoiding saying what you think.
- logicslave 6y agoI'm under the opinion that there is widespread brainwashing, and more than trying to prove my point, I just cant help but comment on it.
- ggm 6y agoBrainwashing about what? Be specific.
- deleted 6y ago[deleted]
- AussieWog93 6y agoIt's the same story in many fields, including non-controversial fields such as Biomedical Engineering (I only use this as an example because I studied it). It's less about uncomfortable topics being actively covered up by nefarious actors, and more about bad ideas dying out naturally. The main reason we don't study correlation between race and IQ is because it isn't useful and doesn't explain anything particularly interesting.
- logicslave 6y agoI will just leave it at this: For evolution to work, IQ has to be heritable, otherwise how did humans evolve intelligence? People who believe in evolution, but not in heritability of personality traits are living in a warped reality. I'm not that interested in proving my point, I'm just more shocked at how many people hold obviously false beliefs.
- AussieWog93 6y ago
- vixen99 6y agoThe Flynn effect appears to be over. I agree with you on culture and genetics. Thomas Sowell is worth reading on this. We should stop categorizing on the basis of 'race' and think about cultural groups and the dynamics of their characteristics. https://www.sciencealert.com/iq-scores-falling-in-worrying-reversal-20th-century-intelligence-boom-flynn-effect-intelligence https://www.sciencealert.com/iq-scores-falling-in-worrying-r...
- concordDance 6y agoI tried to look up graphs of the iq gap over time but such data is harder to find than it was five years ago. I did find that the convergence of math scores seems to have slowed down or stopped though: https://upload.wikimedia.org/wikipedia/commons/5/57/NAEP-longterm-Black-math-ss09-17.gif https://upload.wikimedia.org/wikipedia/commons/5/57/NAEP-lon... For the American "black"-"white" IQ gap itself (and I think it's very important to specify American, as conclusions about "blacks" in the USA are likely to be very misleading if applied to Botswanans for example) the I found a few seemingly contradictory studies, but it looks like the childhood gap is closing quickly (3+ IQ points per decade) while the adult gap is closing much more slowly (<1 IQ point per decade). Do you have any good sources on this?
- SkyBelow 6y ago>it seems that average IQ in large population groups is mostly a function of culture rather than genetics. Probably environment more than culture (unless you are counting environment in that). Just look at the effects nutrition during pregnancy has or the effects lead has on IQ.
- specialist 6y agoFurther, as I understand it, nurture are huge factors, if not the biggest. Poverty, abuse, pollution, zip code, etc. Noob me: Sure, some fraction of IQ is hereditary for individuals. But there's no correlation between hereditary (genetic) IQ and group sizes larger than families, and mosdef none at population levels. PS- Reprehensible is the nicest adjective I can think of for those retrograde beliefs.
- erhk 6y agoIQ is verifiably a tool to exclude people based on race. It used inane things like vocabulary to deign intelligence. It has no merit and is not worth discussing.
- CryptoPunk 6y agoThis is a completely unscientific claim. IQ is extremely well studied by credible scientists and found to be a very reliable indicator of general intellectual ability, as reflected in competence in a wide variety of intellectual tasks.
- sprafa 6y agoYou should read more about IQ and it’s failure to predict success. Like Nassim Taleb has said - IQ just shows you’re not dumb, not that you’re smart. Which you are a perfect example of, I’m sure.
- bloak 6y agoIQ is, by definition, how well you perform at solving a particular kind of puzzle. "Success" means fulfilling whichever criteria you have defined for a particular goal/objective. IQ results are of some use in predicting how well children will do at school, i.e. what exam results they will get after being taught. That's usually a "success criterion" for the school, though not necessarily for the children, who may have other goals in life, e.g. becoming a footballer.
- User23 6y agoPlayers that want to play football in the NFL have to take an IQ test[1] and score decently well. Using a rough conversion[2], NFL teams require a minimum IQ in the low 90s to play, because players below that threshold are incapable of learning the plays[3]. So even for persons who want to play competitive football, a certain level of intelligence is extremely important. I don't know much about soccer beyond pickup games, is it roughly as cognitively demanding as football at the highest levels? [1] https://jobdescriptionandresumeexamples.com/10-important-facts-about-nfl-wonderlic-test/ https://jobdescriptionandresumeexamples.com/10-important-fac... [2] https://wonderlictestpractice.com/how-does-the-wonderlic-correspond-to-the-iq-test/ https://wonderlictestpractice.com/how-does-the-wonderlic-cor... [3] https://clutchpoints.com/patriots-news-new-england-requires-minimum-wonderlic-iq-test-score/ https://clutchpoints.com/patriots-news-new-england-requires-...
- kingsuper20 6y agoWho knows? Maybe intelligence can be tied to handedness, gingerness (heaven forbid!), or body symmetry. A tricky thing to measure given difficulties in testing, lack of twin studies, and the like. Admittedly it would be interesting to take a million people, give them various sorts of cognitive tests, do a DNA sample, feed in biographical details, and let 'er rip on a big ol' computer. There might be outrage and a need to twiddle knobs on the AI or there might be nothing noteworthy. Some Chinese researcher will let us know soon enough.
- dang 6y agoIf you keep using HN for ideological flamewar we are going to have to ban you. We've asked you before to stop, and you've continued to do it. Please stop. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- CryptoPunk 6y agoBrain matter is metabolically very expensive to build, and I assume maintain, so it has to provide a significant evolutionary advantage per mm^3 to make it evolutionarily worth having larger brains.
- concordDance 6y agoIf brain volume doesn't mean much then why is it so big it causes death in childbirth in humans?
- op03 6y agoThere are people doing fine with half of it removed - https://www.inquirer.com/philly/news/local/20160214_20_years_after_surgery__a_full_life_with_half_a_brain.html https://www.inquirer.com/philly/news/local/20160214_20_years...
- f6v 6y agoThere’s a huge difference between “doing fine” in a modern society and in nature where she wouldn’t have survived. The article mentions her case is also rather atypical.
- hanselot 6y agoOpportunity cost is a hell of a thing. After the surgery, she grew introverted, and many of the friends who had supported her in third grade drifted away. Her family and doctors knew her ambitious goals of college and a career would be a struggle, but others were more negative, even cruel. A teacher at a technical high school said she doubted Santhouse would ever be able to do more than answer phones. Even the Johns Hopkins doctors said she'd never drive. Yet, "I was full steam ahead," Santhouse said, recounting how she got her driver's license at 17, excelled on the high school bowling team, and pushed herself through college and on to a graduate degree. "I wasn't going to let [the brain surgery] stop me." I don't think its fair to say that this would be considered a full life by many. But, given your view, perhaps you would volunteer to have this surgery done to prove this? Edit: I suppose you would probably be fine if you consumed the news (propaganda) and embraced leftism.
- fighterpilot 6y agoI believe the facts support a different conclusion: (1) There's been a dramatic increase in our brain size over the last million years, is just a coincidence that we've also gotten way smarter? (2) What about the high correlation between brain volume and IQ within humans? (3) What would the evolutionary purpose be of supporting such an expensive organ if its size is irrelevant?
- _0ffh 6y agoA possible answer would be that greater volume also implies greater surface area (modulo shape).
- TeMPOraL 6y agoAn OS only takes a small part of the computer's overall storage. Imagine you bought one of those high-capacity SSDs off AliExpress, and unbeknownst to you, what you got is a small flash drive in an SSD enclosure, cleverly preformatted to report it's 10x as big as it is. You install your OS on this drive, and happily do your work, but then you start realizing that some files are going missing, even though you're sure you've saved them... Something similar may be happening with the brain - perhaps the core compute runs on the surface layers, but that doesn't mean non-critical functionality isn't occupying the deeper parts, and a person with less of those parts may not realize they have decreased capacity.
- 52-6F-62 6y ago> Something similar may be happening with the brain - perhaps the core compute runs on the surface layers, but that doesn't mean non-critical functionality isn't occupying the deeper parts, and a person with less of those parts may not realize they have decreased capacity. That's at once fascinating and existentially horrifying to me. I need to know more...
- ben_w 6y agoIt definitely happens at some point — I saw it in my mother when her Alzheimer’s progressed to later stages. She only seemed to be aware of her condition in the initial stages. I have wondered if Alzheimer’s preferentially damages certain parts of the brain? And also if eventual death is unpredictable because it depends on when the damage interferes with autonomous bodily functions such as heartbeat, breathing, or gut peristalsis?
- darksaints 6y agoWhy would relative brain size matter? If your brain were 75 percent of your mass but only consists of 1000 neurons, why would that be predictive of high intelligence over a brain that is 1% of mass, but 10 billion neurons? It has always seemed more intuitive to me that absolute brain size would matter far more. Also...brain size might be a decent proxy, but there is a large amount of variation in nature for distribution of neurons. Your brain is a centralized cluster, but we have neurons all throughout our bodies too. With octopuses, neurons are far more heavily concentrated in the tentacles than mammals, and they certainly show extremely high intelligence.
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- bitwize 6y agoIf your brain were 75 percent of your mass but only contained 1000 neurons, then you would probably be the smartest sort of whatever tiny, simple organism you happen to be.
- garbagetime 6y agoMaybe. I feel like there are probably a lot of uses for neurons which don't have that much to do with cleverness
- bloak 6y agoThat sounds plausible to me. I don't have a definition of "cleverness"/"intelligence", but I could believe that in many species most of the neurons are working on processing sensory data or controlling muscles, which isn't the essence of (human) intelligence: you do call a juggler "clever", but a human who is blind and mostly paralysed isn't less "intelligent". I think it has been suggested that the "intelligence" of octopuses might be a side-effect of the huge amount of data processing that is required to control a body without a skeleton.
- hyperpallium2 6y agoI've assumed it's because a larger body, with more cells, needs more neurons to monitor and model it, but it's not compelling. The "law" is mere empirical correlation - e.g. you are smarter than a blue whale. The fantasy that the baby spiders with encephalization quotients (https://wikipedia.org/wiki/Encephalization_quotient https://wikipedia.org/wiki/Encephalization_quotient) off the charts (because their brains displace their digestive systems and partly fill their legs) are more intelligent than humans, appeals to me. I suspect raw intelligence doesn't require many neurons. But spiders aren't social. Parrots are.
- ncmncm 6y agoIt seems as if birds get a lot more intelligence from a given amount of brain than mammals manage. But it is curiously limited. For example, ravens easily understand stuff hanging on the end of a string, and pulling the string up in stages to get it. But they cannot understand pulling a string on a pulley down to bring the titbit up. ("Mind of the Raven: Investigations and Adventures with Wolf-Birds" by Bernd Heinrich)
- RcouF1uZ4gsC 6y agoI wonder if instead of looking at relative size, relative energy expenditure of the brain relative to the rest of the body might be more useful.
- JetAlone 6y agoThat might assume brains all have roughly the same energy efficiency... Personally, I don't mind these heuristics too much, but we should remain focused on a teleological approach to intelligence. Size absolute or relative, energy expenditure, etc... I think the best brain is the one capable of producing the best solutions to complex problems, with the least possible disadvantages.
- erhk 6y agoWe should also consider a carbon tax on the less efficient ones
- boygobbo 6y agoI find the 'expensive tissue hypothesis' (based on brain/gut ratio) quite persuasive. See https://en.wikipedia.org/wiki/Expensive_tissue_hypothesis https://en.wikipedia.org/wiki/Expensive_tissue_hypothesis
- nathias 6y agoBrain/body ratio is not a measure of intelligence but a sign of evolutionary process probably favoring intelligence.
- ggm 6y agoIf you believe in "connectionist" models it's not how big it's how rich the cross connects are.
- rvieira 6y agoFrom my layperson POV, I always assumed body/brain size ratio was simply a way of normalising the volumes to make comparisons between different species, and not an absolute proxy metric for "intelligence".
- sharperguy 6y agoMy complete non-scientists guess about brain size is that large brains are used for storing detailed visual information. So that animals that have to navigate and remember large territories, possible remembering the smallest details in wide open plains or tundras will have larger brains.
- LordGrey 6y agoThose of us with aphantasia[0] might disagree with that. [0] https://en.wikipedia.org/wiki/Aphantasia https://en.wikipedia.org/wiki/Aphantasia
- fsckboy 5y agoInteresting! moving further tangentially related, I wonder what the condition I have is called? I read the Assessment section of that aphantasia article https://en.wikipedia.org/wiki/Aphantasia#Assessment https://en.wikipedia.org/wiki/Aphantasia#Assessment [1] and recalled that my brain has another condition, the inability to self-assess on a numeric scale. There are lots of interesting tests online, personality assessment, etc. and I can't complete them. I get 1/4 of the way in and suddenly the scales seem completely arbitrary and I have no way of deciding where I fall. [1] just a meta footnote to say, aren't HN footnotes dumb, and isn't pasting the link right into the prose a less fussy way to make references?
- LordGrey 5y ago> I get 1/4 of the way in and suddenly the scales seem completely arbitrary and I have no way of deciding where I fall. That sounds a bit like Semantic Satiation, where words (usually when repeated) suddenly stop making sense. I have no actual information about that; your description simply reminded me of it. Discovering I had aphantasia so late in life -- I'm 56 -- just reinforced the knowledge that everyone is wired differently and therefore approaches Life from different directions. I knew that, intellectually, but it was still kind of a slap in the face. [2] [2] No reason for the footnote. I'm just trying to fit in around here. Maybe if I had multiple footnotes it would make more sense....
- redis_mlc 6y agoNot sure how to compare intelligence across species (one idea is length of focus time?), but it would be interesting to make a chart with crows, hornbills, people, and dolphins. The hornbill is the most aware animal that I've seen in zoos - they actively watch the visitors, even beyond their enclosures. This is the first time I've seen somebody domesticate them: https://www.quora.com/What-are-your-thoughts-on-the-hornbill https://www.quora.com/What-are-your-thoughts-on-the-hornbill
- h2odragon 6y agoHow about this: beyond a few structures and functions, "brain mass" is mostly unimportant. The brain is like a tumor, the encysted symbiotic parasite fungal infection that made plants walk and then made them vote. The only meaning "brain to body mass" has, is how "fat" the critters lives were while they stabilized into new shapes. I could probably wiff some more about domesticated animals and how placidity, or the ability to tolerate boredom, might be the biggest effect brains have... or most useful.
- 1970-01-01 6y agoLet me guess at the conclusion: Brains that are better at finding patterns that increase survival success are the actual driving force for brain sizes and therefore we should not say that big brain animals are also intelligent animals. Surprisingly, that was pretty much it.
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- wombatmobile 6y ago> The authors say that these complex patterns urge a re-evaluation of the deeply rooted paradigm that comparing brain size to body size for any species provides a measure of the species' intelligence. The "deeply rooted paradigm" is not what it seems. People aren't saying bigger brain size means X. They'd say something different next year, if that's what was necessary to fit their narrative. What they are really saying is that humans are more entitled to resources than other animals. It's always been that way, whether the metric is brain size, skin colour, religion, ethnicity, nationality, or football team allegiance. Humans find whatever facts are convenient to support their own team. When humans talk about "intelligence", what they really mean is entitlement to resources.
- gloriana 6y agoJust want to throw a pretty interesting observation I read about a few months ago in an Edge essay, but can't find a source on - probably because no one is willing to publish or speak freely on it. Would like to find more information. - There is a difference between average brain mass for human males and females - male brains are about 15% larger by mass than female brains, after correcting for mass difference of the male and female bodies Can we assume brain mass is equivalent to neuron count? Please find me a source!