[scoofy]

>they'd simplify their brain

This is not how evolution works! They are not in control of their breeding. Evolution is not some intelligent agent with goals. It is like a river, responding to to the path of least resistance in reproduction.

Intelligence and/or brain size not a dominant evolutionary factor unless they are specifically bread for intelligence and/or brain size. Domesticated animal's dominant evolutionary qualities have nothing to do with the animal preferences for mating, thus brain size in fairly arbitrary, and we should suspect it to be some sort of drift, rather than rationally getting smaller.

[algebraically]

This is a good point but it does seem like people consistently select for less intelligence because less intelligent animals are more tame and easier to control.

[scoofy]

You don't have evidence for that. You presume that less intelligent animals are easier to control, but that's not at all necessarily true. The smaller brain -> less intelligence isn't even something we know.

[algebraically]

I definitely have evidence that wolves are smarter than dogs. [1][2] You're welcome to nitpick but it's obvious that wolves are smarter than dogs.

1: https://www.youtube.com/watch?v=soe-mONHGMc

2: https://www.studyfinds.org/wolves-smarter-dogs-logic/

[KittenInABox]

That doesn't mean that humans are dumber now, though, nor does it mean that dogs were bred to be dumb, nor does it mean that dumb animals are easier to control. Humans with intellectual disability can in fact be extremely hard to control in my understanding!

[algebraically]

That wasn't the claim. The claim was about the effects of domestication on cognition and at least for dogs it is very obvious they are less intelligent than their non-domesticated counterparts. Same is true for rabbits. So, at the very least, in at least 2 cases it is clear that domestication has lead to a decline in cognitive abilities. It doesn't take much to infer the same is true for people, domestication has reduced selective pressures on cognitive abilities.

If you know of cases and studies where the opposite is true then I'd like to see the research.

[hypertele-Xii]

I think you're conflating biological evolution with evolution as a whole. Technology and culture also evolve. Just differently. Evolution is a much wider aspect of existence than mammalian genetic evolution, or even sexual evolution. I absolutely can simplify my brain consciously, by choosing to remember useful, compact things and by choosing to forget useless, complex ones. And then pass that knowledge through our cultural transfer mechanisms.

[scoofy]

The subject here is biological evolution.