A new study confirms that smiling really can make people (somewhat) happier.

"Conventional wisdom tells us that we can feel a little happier if we simply smile. Or that we can get ourselves in a more serious mood if we scowl," Nicholas Coles, lead researcher on the paper and a Ph.D. student in social psychology at University of Tennessee, Knoxville, said.

"But psychologists have actually disagreed about this idea for over 100 years."

That's because psychologists can’t form a consensus on whether facial expressions can lead people to feel the emotions related to those expressions.

These disagreements became more evidnt in 2016 when 17 teams of researchers failed to replicate a well-known experiment demonstrating the physical act of smiling can make people feel happier.

"Some studies have not found evidence that facial expressions can influence emotional feelings," Coles said. "But we can't focus on the results of any one study. Psychologists have been testing this idea since the early 1970s, so we wanted to look at all the evidence."

Using the meta-analysis statistical technique, Coles and his team combined data from 138 studies testing more than 11,000 participants from all around the world. The results of the meta-analysis shows facial expressions have a small impact on feelings.

For example, smiling makes people feel happier, scowling makes them feel angrier and frowning makes them feel sadder.

"We don't think that people can smile their way to happiness," Coles said. "But these findings are exciting because they provide a clue about how the mind and the body interact to shape our conscious experience of emotion. We still have a lot to learn about these facial feedback effects, but this meta-analysis put us a little closer to understanding how emotions work."

Researchers noted that the facial feedback hypothesis suggests an individual’s experience of emotion is influenced by feedback from their facial movements.

Using random effects meta-regression and robust variance estimates, researchers found that the overall effect of facial feedback was significantly small. The team also found that feedback effects are actually stronger in some circumstances compared to others.

Race goers enjoy the atmosphere during The Melbourne Cup at Flemington Racecourse. Kristian Dowling/Getty Images