Recently, Psychology Today published a feature on the Baining people in Papua New Zealand that has been designated the "dullest culture on earth." In their culture, play is forbidden, with adults sometimes holding children's hands to fire to discourage their normal state. For the Baining, play is seen as the domain of animals, while work is seen as innately human. But, according to a study in the American Journal of Play, researchers theorize that the evolutionary reason behind humans' persistence of play well into adulthood is to help them find mates.

The researchers from Penn State said that many, if not all, species have ways to reveal their biological fitness to mates. For example, they said, peacocks have plumage, just as humans in Western culture have expensive cars. Garry Chick, professor and head of the Department of Recreation, Park, and Tourism Management said that playing can be seen through the same vein. In the distant past, when women met a man who was playful, they saw him as non-aggressive – and therefore less likely to harm them or their children. Men, on the other hand, might see playfulness in woman as signs of her youth and fertility.

The study authors furnished a survey that measured qualities that people preferred in a mate to 164 male and 89 female undergraduates, 18 to 26 years old. The survey initially listed 13 qualities, like kindness, intelligence, and religiousness. They also added three qualities associated with play: playfulness, sense of humor, and being fun-loving.

Of the 16 qualities, men ranked sense of humor as the quality they found most attractive in a significant other. For women, kindness was ranked first, but ranked sense of humor, and being fun-loving, and playfulness as second, third, and fourth respectively. Men ranked being fun-loving and playfulness as third and fifth respectively.

Study authors noted that people's preferences may not necessarily line up with the qualities that their mates exhibit. They also said that their results were colored by the fact that the majority of survey respondents came from a Western culture. In addition, it must be stated that the views of college undergraduates may not be representative of the entire population.

The full study, from the American Journal of Play, can be found here.