Laughter is a form of communication understood by everyone, regardless of cultural and language divides. No matter if it's a silent giggle or a hearty guffaw, we all understand laughter as the universal expression of joy. And now scientists say this seemingly innate behavior may have been borne out of a need to differentiate friend from stranger.
In their recent study, scientists from the University of California, Los Angeles (UCLA) had volunteers listen to clips of laughter recorded between friends, and laughter recorded between strangers. Just from listening to people laughing, the volunteers could tell the relationship of the people they were listening to. Overall, the listeners got the relationship right 61 percent of the time, which is amazing considering the audio clips were only about a second long. As it turns out, when friends laugh together, the guffaws tended to convey more excitement and gusto than when strangers laughed with each other.
And it's not a fluke result either. When the team performed the same experiment in over 20 other societies around the globe, the results were the same. Laughter divulges more than just joy to watchful observers. "It seems that laughter likely played a role in early human social organization and cooperation, and is directly tied evolutionarily to similar vocal sounds in nonhuman primates," said Gregory Bryant, lead author of the study.