Did Humans Evolve Opposable Thumbs So We Could Punch Each Other?
Pow! Mike Nelson/Flickr CC By 2.0 It's thought that our hands are what make us human. Combined with our big brains, our fully opposable thumbs enabled our ancestors to make complex tools to conquer the world. But according to biologist David Carrier of Utah State University, that's not all they were good for. He thinks the human hand's uniqueness was shaped, in part, so we could punch each other in the face. Carrier introduced this off-beat hypothesis a few years ago, to much controversy. Now he and his colleagues have come out with a study that sort of supports but doesn't confirm the idea. In the study, published in the Journal of Experimental Biology, Carrier and his team used the disembodied arms of cadavers to show something that martial artists and street fighters already...