It is no surprise that people like when others are nice to them. A compliment, good grade, or positive work review can even cause people to perform better, as studies (and probably you) have found.

But why? Why is it that people who hear compliments strive to do better, rather than get complacent? Researchers at the National Institute for Physiological Sciences, Nagoya Institute of Technology, and the University of Tokyo, among other Japanese institutions, have found a scientific explanation. According to their study, compliments activate the same region of the brain, the striatum, as cash does, and both encourage people to perform better.

The study researchers trained 48 adults to perform a task that required them to tap items on a keyboard in a specific pattern. Then the adults were split into three groups. One group received personalized, individual compliments from one of the administrators of the study. Another group was forced to watch as other people received compliments. The third group was simply meant to evaluate how they did, as participants, on the test.

When the participants returned to the testing facility the next day, all of the participants were asked to perform the finger test once again. The group that received personalized compliments performed better on the test that day than either of the other groups. Researchers believe that the compliments made them perform better.

Norihiro Sadata, one of the study authors, said in a statement, "To the brain, receiving a compliment is as much a social reward as being rewarded money. We've been able to find scientific proof that a person performs better when they receive a social reward after completing an exercise. There seems to be scientific validity behind the message 'praise to encourage improvement'. Complimenting someone could become an easy and effective strategy to use in the classroom and during rehabilitation."

It is unclear whether the study results would hold true in other cultures. Regardless, it is never a bad idea to give a compliment if you want to motivate someone.

The study was published in PLoS One.