5 ms·

Brain size correlates to cognitive ability quite well within a species. Outside of species, it gets much murkier on account of glial:neuron ratios among other c

by User23 3y ago

Brain size correlates to cognitive ability quite well within a species. Outside of species, it gets much murkier on account of glial:neuron ratios among other confounds. As for whale brains, well who knows. Evolution isn't an optimizing force as you appear to believe, rather it is the tyranny of the merely adequate. The oceans are full of remarkably stupid creatures that haven't changed in hundreds of millions of years on account of having a lot of teeth and swimming well has proved sufficient. And of course there's the interesting question of size efficiency. Vacuum tubes are considerably bigger than transistors, which in turn are considerably bigger than ICs. Perhaps raw size isn't really an interesting metric for cross-architectural brains either?

rramadass 3y ago
> Brain size correlates to cognitive ability quite well within a species. Not quite; it is much more nuanced and not settled - https://neuroscience.stanford.edu/news/ask-neuroscientist-does-bigger-brain-make-you-smarter https://neuroscience.stanford.edu/news/ask-neuroscientist-do...
- concordDance 3y ago
  0.3-0.4 is a decent correlation, though obviously there are other bigger factors.
  - rramadass 3y ago
    The very next para points to the problems associated with forming such a correlation; To be honest, I find these correlation a bit unsettling. Clearly, there is more to intelligence than brain size, or classic geniuses like Albert Einstein, who had an average-sized brain, would have been out of luck! It is important think about how we should actually define intelligence, and to keep in mind that the studies cited above only show a correlation between brain size and a person’s score on an intelligence quotient test. Although IQ is historically the most widely used intelligence measure, by no means does it account for all aspects of human intelligence, nor is it an entirely consistent readout of cognitive ability between individuals. Furthermore, a closer look at the results of the gene-association study reveal that most of the relationship the authors found between HMGA2 gene variations and cranial size could be accounted for by the fact that the gene is also correlated with human height. Correlational studies have only established a weak to moderate linear relationship between brain size an intelligence, which is enough fuel to ensure that the brain size and intelligence hypothesis doesn’t burn out, but does little to explain the true basis of human cognitive capacity. You might also want to look at the paper Decreases in Brain Size and Encephalization in Anatomically Modern Humans i have linked here - https://news.ycombinator.com/item?id=36833133 https://news.ycombinator.com/item?id=36833133
    - User23 3y ago
      The whole IQ is only one measure argument really misses the main lesson from psychometrics. It’s entirely well known that IQ test taking is a specific skill. However it’s also known that there is a g factor that predicts about 50% of performance on basically all tasks with a cognitive component. The other 50% is indeed skill specific. So someone with a slightly above average g factor could still be a world class composer or quarterback. Contrariwise someone with an extremely high g might be very good at many different tasks, but not world class at any. So when one talks about measuring intelligence in a general sense, one ought to be talking about g.
      - tptacek 3y ago
        On the importance or supposed profundity of the g factor, here's Cosma Shalizi: http://bactra.org/weblog/523.html http://bactra.org/weblog/523.html (If you like, skip to "Correlations explain g, not the other way around").
        User23 3y ago
        Interesting read. I’m not inclined to critique it much beyond observing that the author clearly set out with an objective in mind and argued well to that end. My brief response is that the fact that we can find similar patterns in noise doesn’t actually show that the discovery of patterns indicates the data is noise. And of course intelligence is a real and observable thing. Some people really are considerably smarter than others. They have better recall, learn faster, and are able to reach correct conclusions either more quickly or with less information than less intelligent persons. Reducing that difference to a single factor almost certainly is a simplification, but just as we can usefully talk about height without getting caught up on difference in leg, torso, and neck length, we can talk about intelligence similarly.
        tptacek 3y ago
        The article addresses this: for instance, if you were to create a "sound mind and body" score that included "hot or not" results, and the results of the Presidential fitness test, you would inevitably come up with a score that was even more predictive of life outcomes than IQ or g.

by User23 3y ago

rramadass 3y ago

> Brain size correlates to cognitive ability quite well within a species. Not quite; it is much more nuanced and not settled - https://neuroscience.stanford.edu/news/ask-neuroscientist-does-bigger-brain-make-you-smarter https://neuroscience.stanford.edu/news/ask-neuroscientist-do...

concordDance 3y ago
0.3-0.4 is a decent correlation, though obviously there are other bigger factors.
- rramadass 3y ago
  The very next para points to the problems associated with forming such a correlation; To be honest, I find these correlation a bit unsettling. Clearly, there is more to intelligence than brain size, or classic geniuses like Albert Einstein, who had an average-sized brain, would have been out of luck! It is important think about how we should actually define intelligence, and to keep in mind that the studies cited above only show a correlation between brain size and a person’s score on an intelligence quotient test. Although IQ is historically the most widely used intelligence measure, by no means does it account for all aspects of human intelligence, nor is it an entirely consistent readout of cognitive ability between individuals. Furthermore, a closer look at the results of the gene-association study reveal that most of the relationship the authors found between HMGA2 gene variations and cranial size could be accounted for by the fact that the gene is also correlated with human height. Correlational studies have only established a weak to moderate linear relationship between brain size an intelligence, which is enough fuel to ensure that the brain size and intelligence hypothesis doesn’t burn out, but does little to explain the true basis of human cognitive capacity. You might also want to look at the paper Decreases in Brain Size and Encephalization in Anatomically Modern Humans i have linked here - https://news.ycombinator.com/item?id=36833133 https://news.ycombinator.com/item?id=36833133
  - User23 3y ago
    The whole IQ is only one measure argument really misses the main lesson from psychometrics. It’s entirely well known that IQ test taking is a specific skill. However it’s also known that there is a g factor that predicts about 50% of performance on basically all tasks with a cognitive component. The other 50% is indeed skill specific. So someone with a slightly above average g factor could still be a world class composer or quarterback. Contrariwise someone with an extremely high g might be very good at many different tasks, but not world class at any. So when one talks about measuring intelligence in a general sense, one ought to be talking about g.
    - tptacek 3y ago
      On the importance or supposed profundity of the g factor, here's Cosma Shalizi: http://bactra.org/weblog/523.html http://bactra.org/weblog/523.html (If you like, skip to "Correlations explain g, not the other way around").
      - User23 3y ago
        Interesting read. I’m not inclined to critique it much beyond observing that the author clearly set out with an objective in mind and argued well to that end. My brief response is that the fact that we can find similar patterns in noise doesn’t actually show that the discovery of patterns indicates the data is noise. And of course intelligence is a real and observable thing. Some people really are considerably smarter than others. They have better recall, learn faster, and are able to reach correct conclusions either more quickly or with less information than less intelligent persons. Reducing that difference to a single factor almost certainly is a simplification, but just as we can usefully talk about height without getting caught up on difference in leg, torso, and neck length, we can talk about intelligence similarly.
        tptacek 3y ago
        The article addresses this: for instance, if you were to create a "sound mind and body" score that included "hot or not" results, and the results of the Presidential fitness test, you would inevitably come up with a score that was even more predictive of life outcomes than IQ or g.