A study published online on April 12 in the Cell Press journal Current Biology offers some news for parents: even toddlers（初学走路的孩子） have a tendency to follow the crowd. That sensitivity isn't unique to humans either; chimpanzees also appear more likely to pick up habits if "everyone else is doing it." That conclusion comes from evidence that 2-year-olds and chimpanzees are more likely to copy actions when they see them repeated by three of their peers than if they see the same action done by one peer three times.

"I think few people would have expected to find that 2-year-olds are already influenced by the majority," said Daniel Haun of the Max Planck Institutes for Evolutionary¹ Anthropology² and Psycholinguistics. "Parents and teachers should be aware of these dynamics³ in children's peer interactions."

The findings tell us that humans and chimpanzees have shared strategies for social learning, the researchers say. Orangutans（猩猩） on the other hand don't seem to feel the same majority sway.

Prior studies revealed that children are sensitive to peer pressure already at preschool age. The researchers wanted to know whether the majority influences social learning at an even earlier age and in other primate⁴ species as well.

Haun's team built a box with three holes, each a different color. The box delivered a treat only when a ball was dropped into one of those three, colored holes. Toddlers, chimpanzees, and orangutans unfamiliar⁵ with the box were then allowed to watch as four of their same-species peers interacted with the box. The majority of those peer demonstrators had been trained to favor one color over the others.

When the 2-year-old and chimpanzee observers got their turn, they tended to favor the hole favored by their friends. That's in contrast to orangutans, which chose amongst the holes at random⁶.

While the findings might leave some parents in dismay, majority rule probably does have its advantages, evolutionarily speaking. "The tendency to acquire the behaviors of the majority has been posited⁷ as key to the transmission of relatively⁸ safe, reliable, and productive behavioral strategies," Haun says.