Mating and Memory for Faces

Source: Joanna Malinowska/freestocks

How good is your memory for the people you meet? Some claim to never forget a face. On the other extreme are those who suffer from complete face-blindness, and never recognize anyone from one meeting to the next.

Josefa Pandeirada, a psychologist from the University of Aveiro in Portugal, wondered whether our memory for faces might depend on how we encounter them. Along with her colleagues in Portugal and the U.s. she ran an experiment to find out.

In the first part of the experiment, 70 student-aged women saw a series of male faces on a computer screen. Each face appeared alongside a description. For example, “has a good sense of humor”, “likes to eat tuna”, or “usually causes conflicts”. As you can see, some of these descriptions were positive, some neutral, and others negative.

The volunteers’ task was to rate on a 6-point scale each man’s desirability. Half of the volunteers judged the men’s desirability for a long-term romantic relationship. The remaining volunteers judged the men for a long-term working relationship: should he be hired to join their company? Afterwards, all the volunteers completed an unrelated task for three minutes.

At this point, the volunteers thought the experiment was over. But no! They were given one last task: to look at some faces and decide whether each one was new or if they had seen it before. When they recognized someone, the volunteers tried to recall whether they had previously judged that person to be desirable, undesirable, or neutral.

Would their memory for the faces be affected by the type of judgment they had made? Would men judged for a romantic relationship be more easily recalled than men judged for a working relationship?

The quick answer is "yes". Women in the "mating" group were more accurate than those in the "working" group at recognizing faces they had seen before. Women in the "mating" group were also better able to recall whether they had previously classified a man as desirable, undesirable, or neutral: they were correct about 47 percent of the time. Women in the "working" group, who had rated men for their desirability as a work colleague, correctly recalled their judgments only 35 percent of the time (we would expect women who guessed to have been correct 33 percent of the time).

Pandeirada and colleagues suspect that their results can be explained by evolutionary theory. That is, our memory skills likely evolved because they were useful to our ancestors in solving problems. But not all problems are equally important, and it’s likely that decisions about romantic partners are some of the most consequential that humans face.

Scientists working in other labs have also shown that our memory is better for indicators of contamination than cleanliness, and for living creatures than for inanimate objects. Both of these findings are consistent with Pandeirada’s evolutionary explanation because humans are motivated to avoid disease and predators.