Nicholas Wade in The New York Times:
What is the essence of human nature? Flawed, say many theologians. Vicious and addicted to warfare, wrote Hobbes. Selfish and in need of considerable improvement, think many parents. But biologists are beginning to form a generally sunnier view of humankind. Their conclusions are derived in part from testing very young children, and partly from comparing human children with those of chimpanzees, hoping that the differences will point to what is distinctively human. The somewhat surprising answer at which some biologists have arrived is that babies are innately sociable and helpful to others. Of course every animal must to some extent be selfish to survive. But the biologists also see in humans a natural willingness to help.
When infants 18 months old see an unrelated adult whose hands are full and who needs assistance opening a door or picking up a dropped clothespin, they will immediately help, Michael Tomasello writes in “Why We Cooperate,” a book published in October. Dr. Tomasello, a developmental psychologist, is co-director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. The helping behavior seems to be innate because it appears so early and before many parents start teaching children the rules of polite behavior.