The Science of decision-making and peer pressure.


Imagine you're with classmates when a friend from another school approaches. Your classmates start making fun of her. You know it's hurtful, but you want to fit in. You laugh along ... regretting it later.

Or suppose a friend wants you both to audition for a play, but you feel too shy. He pleads with you to do it, so you agree. Later, you're thrilled to see your name on the cast list.

Both of these scenarios are examples of how peers can influence a person's actions--both positively and negatively. As a teen, you can be especially sensitive to peer influence, better known as peer pressure. Science helps explain why.


When a person makes a decision, different parts of the brain spring into action. The brain's limbic system generates an emotional response, and the prefrontal cortex produces rational thinking.

In situations like the two above, "what we are doing is very quickly, and often unconsciously, calculating the rewards and costs of different actions," says psychologist Laurence Steinberg, a leading expert on adolescent peer influence. "When we do this calculation and come to the conclusion that the potential rewards of a particular action outweigh the potential costs, we act in that way."


This decision-making process occurs naturally in humans throughout our lives. But during our teen years, our brains have unique characteristics that impact this calculation.

One reason for the difference in teen decision-making involves a chemical called dopamine in the brain's reward center. Dopamine helps transmit signals in the brain that make people feel happy. The number of brain receptors interacting with dopamine is higher in adolescence than at any other time of life. This means that when a teen is exposed to a reward--such as a compliment--the reward center reacts more strongly than it would for an adult or a child.

In addition, being with friends increases adolescents' sensitivity to rewards. Thus, the presence of peers makes the already sensitive reward system even more sensitive to potential rewards. At the same time, says Steinberg, "when adolescents are criticized or rejected by friends, there is a bigger response in parts of the brain that control negative emotions."

Feeling rewards more strongly and responding more intensely to what peers may think means that there are biological reasons for why teens sometimes decide to do things with their friends that they would never do on their...

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