I do not need to tell you that people help more when they are in good mood. We ask our parents to use their car, and we ask our boss for a raise, when we think they are in a positive mood rather than a negative one. Positive moods have been shown to increase many types of helping behavior, including contributing to charity, donating blood, and helping coworkers (Isen, 1999). It is also relatively easy to put people in a good mood. You might not be surprised to hear that people are more likely to help after they’ve done well on a test or just received a big bonus in their paycheck. But research has found that even more trivial things, such as finding a coin in a phone booth, listening to a comedy recording, having someone smile at you, or even smelling the pleasant scent of perfume is enough to put people in a good mood and to cause them to be helpful (Baron & Thomley, 1994; Gueguen & De Gail, 2003; Isen & Levin, 1972).
In another study, van Baaren, Holland, Kawakami, and van Knippenberg (2004) had students interact with an experimenter who either mimicked them by subtly copying their behaviors outside of their awareness or did not mimic them. The researchers found that people who had been mimicked were more likely to help, by picking up pens that had fallen on the floor and by donating to a charity. It is quite possible that this effect is due to the influence of positive moods on helping—we like people we see as similar to us and that puts us in a good mood, making us more likely to help. In sum, the influence of mood on helping is substantial (Carlson, Charlin, & Miller, 1988), so if you’re looking for help, ask on a nice day, subtly mimic the person’s behaviors, or prepare some good jokes.
But why does being in a good mood make us helpful? There are probably several reasons. For one, a positive mood indicates that the environment is not dangerous and therefore that we can safely help others. Second, we like other people more when we are in good moods, and that may lead us to help them. Finally, and perhaps most important, is the possibility the helping makes us feel good about ourselves, thereby maintaining our positive mood. In fact, people who are in good moods are particularly likely to help when the help that they are going to give seems likely to maintain their positive mood. But if they think that the helping is going spoil their good mood, even people in good moods are likely to refuse to help (Erber & Markunas, 2006).