I mean runaway sexual selection is basically H1, which I updated to being less plausible. See my answer here. (You could comment there why you think my update might be wrong or so.)
I think that first some amount of intelligence in our ancestors evolved as necessary for survival as species—therefore explaining the “coincidence” of intelligence being useful for it—but then it was brought up to our current level as a runaway process. Because nothing other than a runaway process would be enough.
The thing is, ancestral hominids do not need this level of intelligence for survival purpose. Pack hunting, minor tool making, stamina regeneration, and being ridiculously good at throwing things is enough to completely dominate the ancestral environment. But our intelligence didn’t stop at this level, so something else has to be pushing it forward.
And sexual selection is the most obvious candidate. We already have examples of animals with ridiculously overdeveloped traits, due to it, up to the point where they actively harmful to the survival of an individual. We know that humans have extremely complicated mating rituals. At this point, the pieces just fall together.
I agree that sexual selection is a thing—that it’s the reason for e.g. women sometimes having unnecessarily large breasts.
But I think it gets straightened out over long timescales—and faster the more expensive the trait is. And intelligence seems ridiculously expensive in terms of metabolic energy our brain uses (or childbirth motality).
A main piece that updated me was reading anecdotes in Scott Alexander’s Book review of “The Secret of our success” where I now think that humans did need their intelligence for survival. (E.g. 30 year old hunter gatherers perform better at hunting etc than hunter gatherers in their early 20s, even though the latter are more physically fit.)
30 year old hunter gatherers perform better at hunting etc than hunter gatherers in their early 20s, even though the latter are more physically fit.
I’m not sure how it’s relevant. Older hunters are not more intelligent, they are more experienced. Moreover, your personal hunting success doesn’t necessary translates into your reproductive success—all the tribe will be enjoying the gains of your hunt and our ancestors had a strong egalitarian instinct. And even though higher intelligence improves the yields of your labor, it doesn’t mean that it creates strong enough selection pressure to outweighs other factors.
But I think it gets straightened out over long timescales—and faster the more expensive the trait is.
It doesn’t have to happen for a species who is already dominating their environment. As for them it can be the most dominant factor determining inclusive genetic fitness.
And if the trait, the runaway sexual selection is propagating, is itself helpful in competition with other species, which is obviously true for intelligence, there is just no reason for such straightening over a long timescale.
I thought if humans were vastly more intelligent than they needed to be they would already learn all the relevant knowledge quickly enough so they reach their peak in the 20s.
And if the trait, the runaway sexual selection is propagating, is itself helpful in competition with other species, which is obviously true for intelligence, there is just no reason for such straightening over a long timescale.
I mean for an expensive trait like intelligence I’d say the benefits need to at least almost be worth the costs, and then I feel like rather attributing the selection for intelligence to “because it was useful” rather than “because it was a runaway selection”.
I thought if humans were vastly more intelligent than they needed to be they would already learn all the relevant knowledge quickly enough so they reach their peak in the 20s.
There is a difference between being more intelligent than you need for pure survival and being so intelligent that you can reach the objective ceiling of a craft at early age.
I mean for an expensive trait like intelligence I’d say the benefits need to at least almost be worth the costs, and then I feel like rather attributing the selection for intelligence to “because it was useful” rather than “because it was a runaway selection”.
The benefit is in increased inclusive genetic fitness. A singular metric that encorparates both success in competition with other species and with other members of your species due to sexual selection. If the species is already dominating the environment then the pressure from the first component compared to the second decreases.
That’s why I’m attributing the level of human intelligence in large part to runaway sexual selection. Without it, as soon as interspecies competition became the most important for reproductive success, natural selection would not push for even grater intelligence in humans, even though it could improve our ability to dominate the environment even more.
If the species is already dominating the environment then the pressure from the first component compared to the second decreases.
I agree with this. However I don’t think humans had nearly sufficient slack for most of history. I don’t think they dominated the environment up until 20000years [1]ago or so, and I think most improvements in intelligence come from earlier.
That’s why I’m attributing the level of human intelligence in large part to runaway sexual selection. Without it, as soon as interspecies competition became the most important for reproductive success, natural selection would not push for even grater intelligence in humans, even though it could improve our ability to dominate the environment even more.
I’m definitely not saying that group selection lead to intelligence in humans (only that group selection would’ve removed it over long timescales if it wasn’t useful). However I think that there were (through basically all of human history) significant individual fitness benefits from being smarter that did not come from outwitting each other, e.g. being better able to master hunting techniques and thereby gaining higher status in the tribe.
thanks. Can you say more about why?
I mean runaway sexual selection is basically H1, which I updated to being less plausible. See my answer here. (You could comment there why you think my update might be wrong or so.)
I think that first some amount of intelligence in our ancestors evolved as necessary for survival as species—therefore explaining the “coincidence” of intelligence being useful for it—but then it was brought up to our current level as a runaway process. Because nothing other than a runaway process would be enough.
The thing is, ancestral hominids do not need this level of intelligence for survival purpose. Pack hunting, minor tool making, stamina regeneration, and being ridiculously good at throwing things is enough to completely dominate the ancestral environment. But our intelligence didn’t stop at this level, so something else has to be pushing it forward.
And sexual selection is the most obvious candidate. We already have examples of animals with ridiculously overdeveloped traits, due to it, up to the point where they actively harmful to the survival of an individual. We know that humans have extremely complicated mating rituals. At this point, the pieces just fall together.
Thanks!
I agree that sexual selection is a thing—that it’s the reason for e.g. women sometimes having unnecessarily large breasts.
But I think it gets straightened out over long timescales—and faster the more expensive the trait is. And intelligence seems ridiculously expensive in terms of metabolic energy our brain uses (or childbirth motality).
A main piece that updated me was reading anecdotes in Scott Alexander’s Book review of “The Secret of our success” where I now think that humans did need their intelligence for survival. (E.g. 30 year old hunter gatherers perform better at hunting etc than hunter gatherers in their early 20s, even though the latter are more physically fit.)
I’m not sure how it’s relevant. Older hunters are not more intelligent, they are more experienced. Moreover, your personal hunting success doesn’t necessary translates into your reproductive success—all the tribe will be enjoying the gains of your hunt and our ancestors had a strong egalitarian instinct. And even though higher intelligence improves the yields of your labor, it doesn’t mean that it creates strong enough selection pressure to outweighs other factors.
It doesn’t have to happen for a species who is already dominating their environment. As for them it can be the most dominant factor determining inclusive genetic fitness.
And if the trait, the runaway sexual selection is propagating, is itself helpful in competition with other species, which is obviously true for intelligence, there is just no reason for such straightening over a long timescale.
I thought if humans were vastly more intelligent than they needed to be they would already learn all the relevant knowledge quickly enough so they reach their peak in the 20s.
I mean for an expensive trait like intelligence I’d say the benefits need to at least almost be worth the costs, and then I feel like rather attributing the selection for intelligence to “because it was useful” rather than “because it was a runaway selection”.
There is a difference between being more intelligent than you need for pure survival and being so intelligent that you can reach the objective ceiling of a craft at early age.
The benefit is in increased inclusive genetic fitness. A singular metric that encorparates both success in competition with other species and with other members of your species due to sexual selection. If the species is already dominating the environment then the pressure from the first component compared to the second decreases.
That’s why I’m attributing the level of human intelligence in large part to runaway sexual selection. Without it, as soon as interspecies competition became the most important for reproductive success, natural selection would not push for even grater intelligence in humans, even though it could improve our ability to dominate the environment even more.
I agree with this. However I don’t think humans had nearly sufficient slack for most of history. I don’t think they dominated the environment up until 20000years [1]ago or so, and I think most improvements in intelligence come from earlier.
I’m definitely not saying that group selection lead to intelligence in humans (only that group selection would’ve removed it over long timescales if it wasn’t useful). However I think that there were (through basically all of human history) significant individual fitness benefits from being smarter that did not come from outwitting each other, e.g. being better able to master hunting techniques and thereby gaining higher status in the tribe.
Or could also be 100k years, idk