Intelligence is capped on the bottom but it is long-tailed at the top.
This seems wrong to me. From an evolutionary perspective, there shouldn’t be complex new structures that are only occasionally present.
There is a modal human brain. Most particular brains have a few small errors that make them slightly worse. Some have a small mutation that makes them slightly better. The long tail stretches downwards, into the people with severe learning disabilities.
However, It depends what you are measuring, and what scale you are using. Use a scale like Busy Beaver IQ and almost everyone is below average. Because you are streaching out differences at the top of the scale.
There is also a difference between biological intelligence and optimization power. A caveman with the genes for being unusually smart still won’t know much science. It is at least plausible that the median is less than the mean here, but again, it depends on the scale used.
OP’s claim is that intelligence is positively skewed. Counter-points are “most brains are slightly worse” (Donald Hobson) and “you oversample the high-intelligence people, so your claim is biased because of availability” (Ericf).
Both of these counter-points agree with, rather than disagree with, lsusr’s point. Most brains are slightly worse implies positive skew and to the extent that lsusr oversamples high-intelligence people, they are underestimating how positively skewed intelligence is yet still conclude it is positively skewed (caveat: as Donald Hobson says, the measurement approach can be really important here, but for the sake of argument let’s say lsusr is talking about latent intelligence, and our measures just need to catch up with the theory).
Ericf also makes another interesting point- “variation in low intelligence is less identifiable than variation in high intelligence,” 160 vs. 130 IQ people will act differently, but 40 vs. 70 IQ people won’t so much, or at least the IQ test is better at delineating on the high end than low end. I am no expert on the measurement of intelligence, but this point probably shouldn’t just be taken at face value- for example, individuals with Down’s syndrome consistently have IQs less than 70 and getting below 70 is rare, as expected since IQ is designed to be Gaussian. But the implication of that is that as rare (and therefore difficult to dig into) as low IQs are, high IQs are...equally rare (and therefore difficult to dig into).
I agree that OP’s claim should also be subjected to scrutiny -simply saying intelligence is positively skewed doesn’t make it so- but I also don’t find the present set of counter-points either that contradictory or that convincing either. Just my two cents.
I think you are right, and OP fell victim to the Availability heuristic.
4 SD above average is 160 IQ, which is a normal level of “very smart.” Everyone reading this probably personally knows someone around that level. And we can almost see the impact a star programmer, or an Einstein, makes on the world.
4 SD below average is a) not well measured because “nobody” cares once you go below 70 (2 SD); b) not going to be making an impact on society; and c) not going to present too differently than an IQ 70 person—you don’t know if it took the person stocking shelves 1 hour, 1 day, or 1 year of instruction to reach maximum shelf-stocking skill.
This seems wrong to me. From an evolutionary perspective, there shouldn’t be complex new structures that are only occasionally present.
There is a modal human brain. Most particular brains have a few small errors that make them slightly worse. Some have a small mutation that makes them slightly better. The long tail stretches downwards, into the people with severe learning disabilities.
However, It depends what you are measuring, and what scale you are using. Use a scale like Busy Beaver IQ and almost everyone is below average. Because you are streaching out differences at the top of the scale.
There is also a difference between biological intelligence and optimization power. A caveman with the genes for being unusually smart still won’t know much science. It is at least plausible that the median is less than the mean here, but again, it depends on the scale used.
OP’s claim is that intelligence is positively skewed. Counter-points are “most brains are slightly worse” (Donald Hobson) and “you oversample the high-intelligence people, so your claim is biased because of availability” (Ericf).
Both of these counter-points agree with, rather than disagree with, lsusr’s point. Most brains are slightly worse implies positive skew and to the extent that lsusr oversamples high-intelligence people, they are underestimating how positively skewed intelligence is yet still conclude it is positively skewed (caveat: as Donald Hobson says, the measurement approach can be really important here, but for the sake of argument let’s say lsusr is talking about latent intelligence, and our measures just need to catch up with the theory).
Ericf also makes another interesting point- “variation in low intelligence is less identifiable than variation in high intelligence,” 160 vs. 130 IQ people will act differently, but 40 vs. 70 IQ people won’t so much, or at least the IQ test is better at delineating on the high end than low end. I am no expert on the measurement of intelligence, but this point probably shouldn’t just be taken at face value- for example, individuals with Down’s syndrome consistently have IQs less than 70 and getting below 70 is rare, as expected since IQ is designed to be Gaussian. But the implication of that is that as rare (and therefore difficult to dig into) as low IQs are, high IQs are...equally rare (and therefore difficult to dig into).
I agree that OP’s claim should also be subjected to scrutiny -simply saying intelligence is positively skewed doesn’t make it so- but I also don’t find the present set of counter-points either that contradictory or that convincing either. Just my two cents.
I think you are right, and OP fell victim to the Availability heuristic. 4 SD above average is 160 IQ, which is a normal level of “very smart.” Everyone reading this probably personally knows someone around that level. And we can almost see the impact a star programmer, or an Einstein, makes on the world.
4 SD below average is a) not well measured because “nobody” cares once you go below 70 (2 SD); b) not going to be making an impact on society; and c) not going to present too differently than an IQ 70 person—you don’t know if it took the person stocking shelves 1 hour, 1 day, or 1 year of instruction to reach maximum shelf-stocking skill.