What factors influence a teenager’s decision to have sex? Unhesitating, many parents would answer peer pressure, yet a new research collaboration between Utrecht University and the New York State Psychiatric Institute finds peer norms to be more complex than most parents would imagine. In their meta-analysis of adolescent sexuality, the researchers found teens’ sexual behavior was influenced by their perceptions of three distinct factors: how sexually active their peers are, how much their peers approve of having sex at their age, and how much they feel pressured by peers.

What Are Norms?

Sociologists describe norms as group-related beliefs about how to act in certain circumstances. Peer norms include descriptive norms, injunctive norms, and peer pressure. Descriptive norms refer to what you believe most of your peers are doing. After all, you might reason that if others are doing something especially if many others are doing something — it must be good. Injunctive norms refer to how much you believe your peers approve of a certain behavior; you're more likely to do something if you don't think it's wrong. Finally, peer pressure refers to explicit social coercion, such as: What, you've never had sex? What's wrong with you?

The international team of researchers examined 58 published and unpublished studies with data on 69,638 teens in 15 countries. The analysis found that adolescents tended to be more sexually active themselves if they perceived their peers as 1) more sexually active, 2) more approving of sex, and 3) exerting more pressure on them to have sex. “Adolescents who think that their peers engage in sex are more likely to engage in sex themselves,” said Dr. Daphne van de Bongardt, lead researcher of the analysis. “Peers' approval of having sex, or peer pressure to have sex, also matter, but seem to matter less."

Essentially, then, peer pressure was found to have the smallest effect on sexual behavior. However, the 10 studies directly examining this “varied considerably in the way in which peer pressure was measured,” noted van de Bongardt, adding there was a general lack of clarity throughout scientific literature as to what peer pressure entails and how it might best be measured. Looking into gender differences, the researchers also found boys and girls to be similarly influenced by peer norms when it came to sex.

However, one key area of difference exists: A girl’s perception of peers’ high risk sexual behavior more strongly influences her own risk-taking, whereas boys are less influenced in this way. Since taking a risk could result in a girl becoming pregnant or catching an infection, or worse, knowing how peers influence a teen in this particular way might help parents to correctly steer their daughter toward healthy, not harmful, behavior.

Source: Van de Bongardt D, Reitz E, Sandfort T, Deković M. A Meta-Analysis of the Relations Between Three Types of Peer Norms and Adolescent Sexual Behavior. Personality and Social Psychology Review. 2014.