What makes it possible for people to love, hate, help, or betray one another? How do we decode facial expressions? How do we understand and regulate our own emotional experiences? How do we separate the self from the other, make moral judgments, or decide how much money to save for retirement? What causes some people to turn to religious extremism, heroin, or politics? How does the brain fail those with social deficits such as autism? Questions like these sit at the junction of our social, emotional, and biological realities, and they drive the young but rapidly growing field of social neuroscience.
Until a few years ago, the idea that science could elucidate the neural foundations of social phenomena as complex as love, friendship, and trust “just basically seemed ludicrous,” says Janine Simmons, chief of the National Institute of Mental Health’s (NIMH's) program for affect, social behavior, and social cognition. Such “big questions” motivate many scientists to study neuroscience or psychology, she says — but soon they realize that the ability to address such questions is limited by technology. “It’s just recently that people have not been laughed at for taking on these more complex questions,” she says. Scientists seeking to understand the neural mechanisms underlying social cognition and emotion have drawn on a variety of methods, including studies of patients with neurological damage and single-cell recording of brain activity in nonhuman animals. These research tools have proven valuable, but it was the ready availability, starting about a decade ago, of functional neuroimaging technology that fueled an explosion in social neuroscience.