No Two Human Brains Are Alike

The brains of human beings are different from those of every other species of animal, because all species’ brains have been tuned to their lifestyles through millions of years of evolution. A spider’s brain is geared to weaving webs and catching flies, a fish’s brain is tuned for a life in the water, and a human brain is geared to human affairs.

But what mental functions separate us most from other animals? What makes us human? Answering this question is a continuous quest of philosophy, comparative psychology, and neuroscience. Many ideas have been put forward, including consciousness, conscience, creativity, sense of self, the ability to remember where and when events in one’s life took place, a sense of fair play and morality, the ability to solve challenging problems, the ability to invent new strategies, the use of tools, and so forth. Most ideas of the distinction between animals and humans have been disputed by naturalists, ethologists, and neuroscientists, who see elephants mourning together, chimps teaching other chimps new skills that spread through the community, lions taking revenge on hyenas, birds having a good idea of what was going on in the minds of other birds, animals inventing ways to get food that is otherwise out of reach (e.g., crows dropping stones into a half-filled cylinder to raise food that is floating on the water surface to an accessible level). These human observers have also witnessed macaque monkeys making economic decisions in a laboratory setting that are concordant with the results obtained from the sophisticated mathematical equations found in textbooks of modern economic theory for rational decision making under various risk and reward situations.

Although arguments about what makes us