I’ve seen discussions of the jaw and lips and palate and teeth and such related to diet shifts over the last couple million years, and of course more recently speech, but didn’t consider that only humans cook food and maybe are in a hurry to eat, and therefore may need to be able to blow out or chew without burning or whatnot. Hmm.
I do think being in a hurry is a plausible selection mechanism. Maybe you are competing with your peers or need to get away from a dangerous location.
On the other hand, maybe that turns out not to be true. Humans generally eat slower than other predator mammals as far as I can tell (don’t know for sure). We presumably had tribal trust relationships where we were feeding each other out of unity, because we hunted, not competing to eat something we found dead. And cooking implies waiting and cooperation. If speed were a significant issue it would have outweighed cooking and we wouldn’t be where we are. And presumably fire makes it safer to hang out where we are, not less safe. Or if it’s less safe then we carry uncooked food to a safe refuge and cook it there (but again, that means speed isn’t the issue).
Nonetheless, even if competition with peers or need to flee the scene aren’t driving factors, it’s still true that we cook food and it sometimes accidentally can burn us. We all know what that’s like. And if you get injured badly by that, you can’t eat for a while, which is definitely a disadvantage that could be selected against. In a borderline starvation bottleneck, if an impatient person or unaware infant or child gets burned and can’t eat for three days, that may become the difference between life or death.
This also raises the issue of how adults can provide safety to children. Most animals wean early and the noob eats their own food. But maybe the need to be a bit sophisticated about how to cook the food or handle hot food delays that for humans. This may results in longer breastfeeding times or other social behaviour changes.
One thing that I never related to cooking but has been discussed in anthropology in other contexts is pre-chewing. Kissing as affection seems to stem from an adult (probably mom) to infant behaviour of the adult masticates the food and then transfers it to the kid mouth to mouth. This is a transition from breast feeding method that seems to be prevalent in non-technological societies. Instant baby food. This also allows a bit of predigestion. The food adults favour also has some of these qualities. A lot of fast food we like has a lower ingestion overhead that usual food (like a soft McD burger and fries that you can almost eat without chewing, just biting off). We unconsciously find such food more appealing.