Evolutionary tension between larger brains and smaller pelvises in humans

That picked my interest so I dug deeper. The author cites p.252 of Brockman's "What is your dangerous idea?", which is an essay by Prof. Timothy Taylor called "The Human Brain is a Cultural Artifact". Sadly, even though its topic is indeed human brains and pelvises, the essay says nothing of the sort. So Prof. Davies made up the claim, or misattributed the citation and didn't check it.

Because we have big heads relative to pelvis size.

Also mentioned is a conjecture that this means there isn't any extra room for preprogrammed behaviors, so all our intelligence is of the flexible type, which is why we are smart.

It also seems to be an interesting evolutionary adaptation that small male dogs seem to be disproportionally well-endowed to supposedly more easy and naturally mate up-the-size instead of down-the-size as the former leads to easier birth than a significantly mismatched latter would.

If you touch a baby's head you will see that the skull is not fully solid yet. They're also more fragile than other species. e.g: Horses are born and quickly start running.

This is because a baby with a fully developed head could not pass the birth canal.