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Comment by surrealize | Hacker News Reader

There's a point-by-point reply from one of the authors, David Carrier, in the comments:

http://phenomena.nationalgeographic.com/2014/06/10/our-skull...

Frankly, I have nothing but respect for the authors of that paper after reading that comment. Even if they're wrong, which they admit they might be, at least they're working hard to evaluate their hypothesis, and their opponents are a bunch of journalists and internet commenters using terms like "their article is just 'bro science'." Despite the critics' lack of respect, the authors response is polite and informative.

There is a culture of no respect of negative results in science. Although they are as important as positive, for some reason even scientists are actively avoiding to, for example, test old results to confirm them right or wrong, and instead they feel like they must do something absolutely new. After that there comes many contradicting studies and nobody putting much effort in resolving them.

Carrier's hypothesis is interesting and well argued, but only time will tell if it stands up to further scrutiny. This is the scientific process. Yong, on the other hand, is just defending his own preconceptions. While I agree with him that the established theory of changing diet/changing dentition is very well supported, Carrier's theory doesn't necessarily contradict it. Both of these theories could have shaped the faces of our ancestors and, eventually, us.

I would love to see models testing how well the skulls of different human ancestors and humans themselves stand up to blunt blows, both head-on and oblique ones. It's possible that the skulls of modern humans, despite being more gracile, might perform surprisingly well thanks to the force-spreading properties of our parabolic dental arcades. i.e. If you hit a human in the side of the jaw you're hitting a self-buttressing arc of bone and teeth. If you hit the U-shaped jaw of an australopithecine on the side, you're hitting a straight wall.

Yong, on the other hand, is just defending his own preconceptions.

When I take into account that the author of the submitted article is science writer on evolution topics Brian Switek and not general science writer Ed Yong, I wonder what defending of preconceptions is going on in your comment.

AFTER EDIT: After I first posted this, I looked up how the first attested use of stone tools by early hominins compares in time with the hypothesized change in facial features discussed in the article, and I see there is some dispute about the very earliest regular use of stone tools, but that definitely precedes the emergence of Homo sapiens by far, and may go back to the time of some of the later australopithecines. Using stone tools as weapons (even just picking up and throwing rocks) was surely a game-changer in fights.

> Carrier's hypothesis is interesting and well argued, but only time will tell if it stands up to further scrutiny.

I have experience of martial arts, on and off, for fifteen years. A few months ago I was having a go on a punch bag, which weighed over 100 pounds. The elbow strikes I was swinging at it would make it rise about 4 to 5 feet in the air, almost above the fulcrum. I was afraid that I might rip the rope it was attached to.

If I were to elbow this hypothesis it would never stand up again, and unlike my fist it wouldn't break.

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