This research challenges the classically accepted view that reduction of tooth size in hominins is linked with having a larger brain. The reasoning is that larger brains allowed hominins to start making stone tools and that the use of these tools reduced the need to have such large chewing teeth. But recent studies by other authors found that hominins had larger brains before chewing teeth became smaller, and they made and used stone tools when brains were still quite small, which challenges this relationship.
The new study evaluates this issue by measuring and comparing the rates at which teeth and brains have evolved along the different branches of the human evolutionary tree.
“The findings of the study indicate that simple causal relationships between the evolution of brain size, tool use and tooth size are unlikely to hold true when considering the complex scenarios of hominin evolution and the extended time periods during which evolutionary change has occurred,” said Aida Gómez-Robles, lead author of the paper and a postdoctoral scientist at GW’s CASHP. Paper. (paywall) – Aida Gómez-Robles, Jeroen B. Smaers, Ralph L. Holloway, P. David Polly, and Bernard A. Wood. Brain enlargement and dental reduction were not linked in hominin evolution. PNAS, 2017 DOI: 10.1073/pnas.1608798114More.
Another simple explanation shot to Hull.
Part of the problem, as noted earlier, is that once we have a lot of information, the story begins to read like a history, not a theory. Doubtless, some big-brained people realized that they could spare their teeth by using stone tools. But that wouldn’t make their teeth smaller. Some small-toothed people might likewise survive if they realized that they could use stone tools. But the relationship between size and survival is complex…
If I were writing a Clan of the Cave Bear potboiler, I would have the question turn on whether big teeth were considered attractive or even safe… remember, we are probably already at the point where such considerations would hlp determine parenthood … 😉
See also: Study: Human brain not exceptional? Every so often something exquisitely stupid turns up, something worth celebrating…
Large human brain size easily explained? Sometimes, we devote space to a really dumb idea about how human beings came to be the way we are.
The search for our earliest ancestors: signals in the noise
Human origins: The war of trivial explanations
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