Monkey See, Monkey Do: Humans Aren't the Only Ones Picking up on Social Norms, Study Shows

The phrase, "when in Rome," usually holds true for humans. We adopt the behaviors of others when on their home turf. Now, researchers have discovered that monkeys apparently do the same, giving a whole new meaning to "monkey see, monkey do."

When humans visit a new place or culture, they tend to seek out local knowledge. These new findings could prove that this particular trait is evolutionary in nature. Surprisingly, though, the researchers didn't set out to study the way monkeys conform to those around them. Instead, the scientists wanted to study wild vervet monkeys in South Africa to test how strongly their infants are influenced by their mothers' habits.

In the initial study, the researchers provided two groups of wild monkeys with a box of corn dyed pink and another box of corn dyed blue. In one group, the blue corn was made to taste repulsive, and the monkeys learned to eat only the pink corn. In the other group, the opposite was true--the pink corn was the type that was repellent.

After a new generation of infants was born, the monkeys were offered both colors of food with neither of them tasting badly. However, the adult monkeys seemed to remember which color they preferred.  The researchers saw that the infants copied the rest of the group, only choosing the preferred color of corn.

The study, though, took on a whole new angle when male monkeys began to migrate between groups during the mating season. Researchers found that out of the 10 males that switched groups, all but one switched to eating the new color of corn almost immediately after being introduced to the local norms.

"The males' fickleness is certainly a striking discovery. At first sight, their willingness to conform to local norms may seem a rather mindless response--but after all, it's how we humans often behave when we visit different cultures," said Andrew Whiten, one of the researchers, in a news release. "It may make sense in nature, where the knowledge of the locals is often the best guide to what are the optimal behaviors in the environment, so copying them may actually make a lot of sense."

The findings are experimental proof that "cultural transmission" can occur in wild monkeys and primates. It also reveals how the same traits may have evolved in humans over time, and could explain our tendencies to adopt local social norms when visiting different places.

The findings are published in the journal Science.