The Body: A Guide for Occupants

by Bill Bryson

his book Into the Gray Zone, Owen discusses the case of a patient named Amy who suffered a serious head injury in a fall and for years lay in a hospital bed. Using an fMRI scanner, and carefully watching the woman’s neural responses when researchers asked her a series of questions, they were able to determine that she was fully conscious. “She had heard every conversation, recognised every visitor, and listened intently to every decision being made on her behalf.” But she was unable to move a muscle—to open her eyes, scratch an itch, express any desire. Owen believes that something in the region of 15 to 20 percent of people thought to be in a permanent vegetative state are in fact fully aware. Even now the only certain way to tell if a brain is working is if its owner says it is. Perhaps nothing is more unexpected about our brains than that they are much smaller today than they were ten thousand or twelve thousand years ago, and by quite a lot. The average brain has shrunk from 1,500 cubic centimeters then to 1,350 cubic centimeters now. That’s equivalent to scooping out a portion of brain about the size of a tennis ball. That’s not at all easy to explain, because it happened all over the world at the same time, as if we agreed to reduce our brains by treaty. The common presumption is that our brains have simply become more efficient and able to pack more performance into a smaller space, rather like cell phones, which have grown more sophisticated as they have contracted...