caveman
Explanation
This comic is a short, punchy joke about the "unleash your inner caveman" trope popular in certain self-help and masculinity movements.
In the top panel, a motivational speaker-type figure shouts "Bros! It's time! Time to unleash your inner caveman!" to a crowd of enthusiastic men who respond with "YEAH!" and "WOOO!"
The bottom panel is the punchline, delivered as a dry narrator caption: "Later, the men engaged in a cooperative system of social reciprocity in order to make good use of scarce resources in a hunter-gatherer society."
The joke subverts the expectation that "unleashing your inner caveman" means acting aggressively, primitively, or hyper-masculinely. In reality, anthropological research shows that actual hunter-gatherer societies were highly cooperative, egalitarian, and dependent on social reciprocity and resource-sharing. The "inner caveman" isn't a chest-thumping brute -- it's a community-minded cooperator.
The humor works because it deflates the macho fantasy by replacing it with a boringly accurate anthropological description, written in the driest possible academic language. It's a pointed critique of the pop-culture misunderstanding of prehistoric human behavior.