By Catherine A. Sanderson, Amherst College
Our need to form close bonds with other people is fundamental and is the single best predictor of our happiness and even influence how long we live. Friendships, family relationships—all play a substantial role in our psychological and physical well-being. However, most research in psychology has focused on romantic relationships, especially interpersonal attraction. Let’s see what research shows.

Proximity Breeds Attraction
The first research on close relationships focused on interpersonal attraction. It studied, basically, the factors which leads someone to develop positive feelings towards another person.
They found one of the most important predictors of attraction to be, what psychologists describe as, proximity. Simply put, it refers to how much one gets to spend time with someone. This, by itself, breeds attraction. A person is more likely to become friends with someone if they have regular contact with them, such as in their dorm, or apartment building, or neighborhood.
Curiously, this contact doesn’t have to be extensive; students who sit next to each other in a class are more likely to become friends, even when the seating is random, one assigned by the instructor.
One of the earliest studies to test the role of proximity found that college students were more likely to become friends with those who lived close by—in their hall, in their dorm—than those who lived farther away. And yet, it’s not just that we get to know people better. Simply regularly seeing someone makes them more familiar, and in turn, seem more attractive.
The Power of Greater Exposure
In a creative study to test the power of greater exposure, researchers asked four different women—who were similar in age and appearance—to attend various large college lecture classes. Some of the women attended a particular class five times, others 10 times, and still others 15 times. Researchers then asked students in each of the classes to rate the visitor’s attractiveness. The more classes a woman visited, the more attractive she was rated by the students in that class.
This mere-exposure effect explains why songs we hear regularly on the radio, or even advertising jingles, start to grow on us over time. It also explains why people rate mirror-image photos of themselves as more attractive than regular photos, whereas their friends and dating partners prefer the regular photos. We most often see ourselves in the mirror, so it’s our mirror image that is more familiar to us.
This article comes directly from content in the video series Introduction to Psychology. Watch it now, on Wondrium.
Matching Hypothesis
Another key factor in influencing interpersonal attraction is similarity. This is the so-called matching hypothesis. We like people who are similar to ourselves in all sorts of ways: people who share our attitudes, values, and interests; people who are similar to us in age, religious beliefs, socioeconomic status, race, even length of ear lobes. We also tend to seek out and find romantic partners who are at roughly our own level of physical attractiveness.
Why is similarity such a powerful force? Having things in common may make it easier to get along with someone. If we both enjoy the same types of activities, or music, or food, it’s probably easier to find things to do together. Similarity may also reduce conflict about politics, religion, or money.
Opposites Attract?
This finding about the benefits of similarity may be a bit surprising since we so often hear about ‘opposites attract’. But the research doesn’t really bear this out. Opposites may attract briefly, as people who are really different can seem exciting. But this novelty wears off fast.
Instead, research consistently finds that people who are similar in terms of their personality traits are more likely to become friends. They are also more likely to become romantically involved.

And it’s not just similarity in personality traits that matters. One study, published in 2017, examined the Facebook accounts of more than 45,000 people. People with similar patterns of ‘likes’ of products, famous people, books, and so on, were more likely to be friends with one another. There was an even stronger association between liking similar things seen between romantic partners.
Physical Attraction and Innate Preferences
Of course, physical attractiveness plays a major role in determining whether we find someone appealing. But what’s more interesting is what we find attractive.
To begin with, there are particular facial features that are seen across cultures as, generally, appealing. Both men and women prefer facial features that indicate youth—big eyes, a small nose, prominent cheekbones. Even babies prefer to look at faces that adults consider attractive rather than at unattractive faces. This shows that it’s not simply that we learn what is attractive from our culture, but that such preferences are innate.
We also prefer faces that are more symmetrical, perhaps because symmetry is a cue to health. Although we might expect that unusual or unique faces would grab our attention, they don’t, at least not in a good way.
Attractiveness Influences Our Evaluation of People
One fascinating study published in 1990 showed people faces that were composites, made up by combining between 2 and 32 different faces. The more faces that were averaged together, the more attractive its rating. Why? One possibility is that average faces are more similar to those we see regularly, another sign of the value of familiarity and mere exposure.
To conclude, it is often observed that, physical attractiveness influences our evaluations of people in all sorts of other situations, beyond romantic partners. Physically attractive people tend to have higher starting salaries and bigger raises. They are less likely to be found guilty of committing a crime, and if they are found guilty, they receive lower bail and smaller fines. Professors who are more attractive get better teaching evaluations from their students. Attractive waiters receive bigger tips.
Common Questions about Romantic Relationships and Interpersonal Attraction
One of the most important predictors of attraction is, what psychologists describe as, proximity. Simply put, it refers to how much one gets to spend time with someone.
Even babies prefer to look at faces that adults consider attractive rather than at unattractive faces. This shows that it’s not simply that we learn what is attractive from our culture, but that such preferences are innate.
We prefer faces that are more symmetrical, perhaps because symmetry is a cue to health. Although we might expect that unusual or unique faces would grab our attention, they don’t, at least not in a good way.