BEIJING, March 19 (Xinhuanet) -- Laughter is often said to be "the best medicine," and now a recent study reveals a hearty laugh may not only make you feel better, but also can make you more cooperative and altruistic toward strangers.

    Laughter is a universal human behavior previous studies have shown acts as a "social lubricant" and promotes group cohesiveness. In this new study, researchers tested whether this sense of closeness would promote altruistic behavior.

    Study participants watched either a funny or a serious video, and then played a game with strangers to see how laughter affected the balance between group interest and self-interest during the game-play.

    Each person was given a small sum of money (about 5 U.S. dollars) and told they could invest it in either a private fund or a group fund -- they would get back whatever they put in the private fund, while whatever was contributed to the group fund would be doubled and split evenly among group members, regardless of how much each person put in.

    The researchers found laughter made strangers more likely to invest in the group fund, and so increased their sense of altruism.

    "This study may have important implications for the way charities or organizations could increase the level of received donations," said Mark van Vugt of the University of Kent, lead author of the unpublished study.

    The study also suggested laughter increases endorphin levels, which are known to be part of the body's mood-lifting chemistry.

    Laughter may have had evolutionary importance by promoting group bonding, which could have enabled our early ancestors to work together to cope with a hostile environment, van Vugt said.

    (Agencies)