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Comment by mudil | Hacker News Reader

Human brain is like a peacock tail: it's a product of the sexual selection. It's too huge of an organ. There seems to be only one way for evolution to produce an organ that is too huge and too out of proportion to the rest of the body (as well as compared to the same organ in other species). The mechanism for such an organ is always sexual selection. It were not sexually selected, it would not confer enough fitness in itself relative to its high maintenance costs (a quarter to a fifth of the energy and oxygen consumed by a human).

There is a reason movie stars, famous people, artists, etc are all sex symbols. Our brain wired to treat them this way. There is a reason we produce art and music in the first place: they are byproducts of sexual selection. It's a great topic to learn about!

Some references on this topic:

https://doi.org/10.1371/journal.pone.0000062

https://en.wikipedia.org/wiki/The_Red_Queen:_Sex_and_the_Evo...

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Couldn't our proclivity to kill one another also have a hand in it? In some societies the murder rate for males was up to 40%, surely that sort of pressure must select for, among other things, cunning?

Chimpanzees kill one another and they’re just extraordinarily strong, and haven’t evolved human level intelligence because of it. Being able to rip off someone’s arms is more useful than being clever of violence were purely the answer.

The Macedonians took over the Greeks, who were more “clever” than the Macedonians. The Mongols took over China, but the Chinese are more “clever”. Scythians didn’t even have writing.

So, I think you can kill a whole lot of people without being the most cunning.

I'm not convinced that's a complete argument.

Rather there's a fix point: The brain is adapt at increasing its size. That's what everything does: Growing. The brain is just especially good at it.

The advantage also manifests in the "schema of childlike characteristics" (Kindchenschema) which includes a big head. So it's evidently also important for affection on a different level: child care and protection.

There are pretty bold statements in your comment, that may be countered with a lack of constraints on the growth. Intelligence affords fitness in myriads of ways, of course.

> Human brain is like a peacock tail

I don't think so. Curious detail about that tail: The females don't have it.

You better believe that peacock tail is a sexually selected trait by females in males.

And that makes it like the human brain like... ?

It makes it an organ of sexual attraction. Just like the brain, an organ of sexual attraction.

:eagerly awaits all the sexy peacock halloween costumes:

This. Kept scrolling down, wondering when I was going to see this comment. Related to language, too. You don't need complex language in groups of social primates for survival. When you see it in nature, like in birds and whales, it's about finding a mate.

>When you see it in nature, like in birds and whales, it's about finding a mate.

Not exactly, at least for whales. The humpback whale song's function has not been fully understood. The initial hypothesis that it is a vocal display for females has not been supported, since females do not approach singing whales, and whales sing all over the place, not just at the breeding grounds. So the function of a humpback song might not be solely to find a mate, or might not be related to reproduction at all.

https://www.the-scientist.com/features/the-mystery-of-whale-...

Furthermore, you do need a complex communication system for complex social groups. For example, there are two bottlenose dolphin ecotypes:coastal and offshore. Coastal ecotype is a small fission-fusion society and we see a somewhat simple vocal repertoire. The offshore ecotype lives in big groups and they have very complex vocal repertoire. The bottom line is, at least for cetaceans, we still do not have enough data and understanding to realy argue about the complexity of their communication system one way or another. But it definitely goes beyond of just being "about finding a mate"

This is the best comment on this subject, yet somehow this comment is at the bottom of the page. This is an example of all the things I nowadays find frustrating with Hacker News. The best comments don't get upvoted any more.

I didn't downvote it, but there are a number of things that made me sigh, so this may partly clarify other people's sentiments if they happen to be similar:

-The tone of the comment is very matter-of-fact and peremptory, as if that explanation was obviously the only one and not just one among the dozens that have been put forward by the community so far, all having more solid support.

-The lack of proper sourcing. A plos one and an evopsych pop sci book do not count as proper sourcing.

-The expression "brains are wired". At least they didn't say "hardcoded", but still. It's as lousy as people calling DNA source code.

-The quasi-Freudian mindset some people demonstrate by seeking to placate sexual selection onto everything that arises through evolution.

-The very loose attempt to apply this argument to present-day cultural phenomena. I find it too easy.

-Basically anything involving evopsychy explanations for anything is very likely to be sigh-worthy.

Before some of you come out of the woodwork (yes, you) and jump at the argument with more plos one citations and retorts from whoever is the flavorful evopsych specialist of the month: yes, I am aware sexual selection is a thing, I partly work on it. Yes, I know evopsych shouldn't be dismissed off-hand. No, I am still not willing to have the discussion you're about to engage me with. To be honest I don't know many scientists who are, it just feels fruitless for us.

"Basically anything involving evopsychy explanations for anything is very likely to be sigh-worthy."

I think you misread the parent comment, as well as mine. Consider this:

"Human brain is like a peacock tail: it's a product of the sexual selection. It's too huge of an organ."

That doesn't reference evolutionary psychology, but rather, that describes Fisherian Runaway:

https://en.wikipedia.org/wiki/Fisherian_runaway

Fisher pre-dates evolutionary psychology/behavioralism by several decades. Fisher put his theory forward back in the 1930s.

I agree with you that most of the modern evpysch stuff is poorly thought out.

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