Immunology

There is no such thing as objectivity when it comes to your friends: According to a new study, people evaluate their friends' behavior more positively than do strangers, regardless of actual performance on a series of tasks. Researchers say that we should then think twice before allowing people who know each other to be in positions to judge each other - from job interviews to legal settings.

"In judging people we already know, we are more or less unable to ignore our previously established images of those people," says Daniel Leising of Technische Universit-t Dresden. The new study, published today in Personality and Social Psychology Bulletin, examines how real people evaluate the behavior of themselves, their friends, and strangers. Psychologists know that people hold a number of biases when evaluating others, but most studies to date on this issue have used written descriptions of the behavior of hypothetical persons. "This is one of the few studies that investigated judgments of people's actual behavior," Leising says.

Leising and colleagues recruited pairs of friends for the study, asking them first to describe each others' personalities and then several days later, videotaped them participating in standardized, challenging situations in the lab. The tasks ranged from answering general knowledge questions, such as "How high is Mount Everest?," to a role-playing exercise in which participants had to call a "neighbor" (played by an actor) and demand that she turn down the volume on her stereo, to telling a joke of his or her own choice. The participants, their friends, and strangers then evaluated the videotapes, each about 90 seconds long.

"This way, we could compare different views on the exact same behaviors with one another," Leising explains. "If different people watch the exact same videotapes but interpret them differently, then the different interpretations may not be rooted in what they just saw, but must be explained in terms of something else."

The research team found that they could predict how participants would judge their friends' behavior based on what they thought of them in advance, even before watching their videotaped behavior. "By statistically controlling for strangers' ratings of the same behavior, we could show that there are two kinds of systematic bias in such behavior judgments," Leising says.

First, we judge the behavior of people we know in ways that are consistent with our general attitude toward them, so we attribute positive qualities to the behavior of people we like. Also, we judge people we know to match our specific impressions of them: For example, if we think of someone as being generally talkative, we will judge that person to be more talkative in specific situations beyond what a stranger would see in the very same behavior.