HUMANS ARE UNLIKELY to win the animal kingdoms prize for fastest, strongest or largest, but we are world champions at understanding one another. This interpersonal prowess is fueled, at least in part, by empathy: our tendency to care about and share other peoples emotional experiences. Empathy is a cornerstone of human behavior and has long been considered innate. A forthcoming study, however, challenges this assumption by demonstrating that empathy levels have been declining over the past 30 years.

The research, led by Sara H. Konrath of the University of Michigan at Ann Arbor and published online in August in Personality and Social Psychology Review, found that college students self-reported empathy has declined since 1980, with an especially steep drop in the past 10 years. To make matters worse, during this same period students self-reported narcissism has reached new heights, according to research by Jean M. Twenge, a psychologist at San Diego State University.

An individuals empathy can be assessed in many ways, but one of the most popular is simply asking people what they think of themselves. The Interpersonal Reactivity Index, a well-known questionnaire, taps empathy by asking whether responders agree to statements such as I often have tender, concerned feelings for people less fortunate than me and I try to look at everybodys side of a disagreement before I make a decision. People vary a great deal in how empathic they consider themselves. Moreover, research confirms that the people who say they are empathic actually demonstrate empathy in discernible ways, ranging from mimicking others postures to helping people in need (for example, offering to take notes for a sick fellow student).

Since the creation of the Interpersonal Reactivity Index in 1979, tens of thousands of students have filled out this questionnaire while participating in studies examining everything from neural responses to others pain to levels of social conservatism. Konrath and her colleagues took advantage of this wealth of data by collating self-reported empathy scores of nearly 14,000 students. She then used a technique known as cross-temporal meta-analysis to measure whether scores have changed over the years. The results were startling: almost 75 percent of students today rate themselves as less empathic than the average student 30 years ago.

Whats to Blame?
This information seems to conflict with studies suggesting that empathy is a trait people are born with. For example, in a 2007 study Yale University developmental psychologists found that six-month-old infants demonstrate an affinity for empathic behavior, preferring simple dolls they have seen helping others over visually similar bullies. And investigators at the Max Planck Institute for Evolutionary Anthropology in Leipzig have shown that even when given no incentive, toddlers help experimenters and share rewards with others. Empathic behavior is not confined to humans or even to primates. In a recent study mice reacted more strongly to painful stimuli when they saw another mouse suffering, suggesting that they share the pain of their cage mates.

But the new finding that empathy is on the decline indicates that even when a trait is hardwired, social context can exert a profound effect, changing even our most basic emotional responses. Precisely what is sapping young people of their natural impulse to feel for others remains mysterious, however, because scientists cannot design a study to evaluate changes that occurred in the past. As Twenge puts it, you cant randomly assign people to a generation.

There are theories, however. Konrath cites the increase in social isolation, which has coincided with the drop in empathy. In the past 30 years Americans have become more likely to live alone and less likely to join groupsranging from PTAs to political parties to casual sports teams. Several studies hint that this type of isolation can take a toll on peoples attitudes toward others. Steve Duck of the University of Iowa has found that socially isolated, as compared with integrated, individuals evaluate others less generously after interacting with them, and Kenneth J. Rotenberg of Keele University in England has shown that lonely people are more likely to take advantage of others trust to cheat them in laboratory games.

The types of information we consume have also shifted in recent decades; specifically, Americans have abandoned reading in droves. The number of adults who read literature for pleasure sank below 50 percent for the first time ever in the past 10 years, with the decrease occurring most sharply among college-age adults. And reading may be linked to empathy. In a study published earlier this year psychologist Raymond A. Mar of York University in Toronto and others demonstrated that the number of stories preschoolers read predicts their ability to understand the emotions of others. Mar has also shown that adults who read less fiction report themselves to be less empathic.

Whereas the sources of empathic decline are impossible to pinpoint, the work of Konrath and Twenge demonstrates that the American personality is shifting in an ominous direction. Still, we are not doomed to become a society of self-obsessed loners. Konrath points out that if life choices can drive empathy down, then making different choices could nurture it. The fact that empathy is declining means that theres more fluidity to it than previously thought, she says. It means that empathy can change. It can go up.