Early humans swapped bite for brain 18:00 24 March 04 NewScientist.com news service Humans owe their big brains and sophisticated culture to a single genetic mutation that weakened our jaw muscles about 2.4 million years ago, a new study suggests. The slack muscles relaxed their hold on the human skull, giving the brain room to grow. Other primates remained stuck with mighty muscles that squeezed the skull in a vice-like grip. The finding is "pretty amazing", says Peter Currie, an expert on skeletal muscle development at the Victor Chang Cardiac Research Institute in Darlinghurst, Australia: "Changes in muscle anatomy are...
