When you think of peer pressure, what do you think of? Most people think of teenagers being swayed to smoke, drink, do drugs, or have sex by the crowd as one particularly pushy friend says something like, "Everybody's doing it." But a study published in Current Biology has found that toddlers are also swayed by peer pressure, choosing to do something if the crowd is doing it.

Daniel Haun, from the Max Planck Institute for Evolutionary Anthropology in Germany, Yvonne Rekers, from the Max Planck Institute for Psycholinguistics in the Netherlands, and Michael Tomasello, from the University of Portsmouth in the United Kingdom, studied the behavior of toddlers as young as 2 years old, chimpanzees and orangutans.

All three of the species were required to learn how to perform a simple task: how to put a ball into a box. All three groups watched members of their own species perform the task. They either watched three individuals put the ball in the box one time each, or they watched one individual put the ball in the box three times. After observing, the toddler, chimpanzee and orangutans were asked to copy what they had just watched.

The researchers found that toddlers were more likely to recreate closely what they had seen if they had watched three people, rather than just one. They would not only put the ball in the box, but put the ball in the exact same box that they had just seen the group choose. Chimpanzees followed the group at even higher rates than the toddlers did. Interestingly, orangutans were an outlier, behaving the same whether the behavior had been modeled by three people or just one.

Haun theorizes that this behavior makes sense from an evolutionary perspective. Following the group could help humans and animals learn new behaviors and avoid dangers.

Next researchers want to see if toddlers will copy the actions of a group even if they know that it is wrong, like teenagers and older children sometimes do. The evolutionary benefit of those behaviors have yet to be determined.