Those "Practice random acts of kindness" bumper stickers may be preaching more wisdom than we realized.
While performing small, kind gestures every day helps others, a new study by Yale and UCLA researchers suggests it may also diffuse our own stress, improving our mental health.
"The take-home message is that when we are stressed and we help others, we can also end up helping ourselves," study author Emily Ansell, assistant professor of psychiatry at Yale University School of Medicine, told CBS News.
Lab-based studies have shown that giving to others can help people cope with stress and boost their positive emotions, said Ansell, but she and colleagues wanted to investigate whether the same holds true in the real world. They asked 77 adults, ranging in age from 18 to 44, to use a study-provided smartphone to report their daily feelings and experiences over a two-week period.
Every night, the participants received an automated phone reminder that prompted them to complete a daily assessment: to report any stressful life events they experienced that day at work or school or in their personal lives at home, including any financial problems or health issues. The total number of events was the measure of their daily stress level, said Ansell.
They were also asked to report whether they had engaged in various helpful behaviors, simple acts such as opening a door for someone else, helping a child with schoolwork, loaning money or an item of value to someone else (clothes, a car, or a tool, for example), or asking another person if they needed help that day.
The participants also completed a daily survey that measured their emotion, and they were asked to rate their mental health each day, rating it from 0 for poor to 100 for excellent.
Helping behaviors seemed to buffer the negative effects of stress on a person's well-being, the authors found. Those who reported performing more acts of kindness showed no dips in positive emotion or mental health. And they had lower increases in negative emotion in response to high daily stress.
"People overall did one or two acts of kindness per day, but what was most important was when they did more than one or two per day, we saw a benefit to their well-being," Ansell said.
People who reported lower-than-usual helping behaviors also reported lower positive emotion and higher negative emotion in response to high daily stress.
It was surprising how strong and uniform the effects were across daily experiences, said Ansell, whose research is published in Clinical Psychological Science, a journal of the Association for Psychological Science.
Ansell plans additional research involving more ethnically and culturally diverse populations.
Another avenue for future study, she said, is to determine whether actively encouraging people to engage in more acts of kindness and helpfulness can improve mood and mental health.
"It may be particularly relevant for people dealing with a lot of stress who are at risk for depression relapse," she said.
Ansell said the findings are especially appropriate for this time of year, the season of giving.
"A lot of the time, we find that our daily stress goes up over the holiday season. We have a lot going on. There can be a lot of different social gatherings and things like that. So when you're out and about having a stressful day, think about doing one of these helpful things: help someone out at the store, hold a door or elevator," said Ansell. "It might help you feel a little better in terms of your own mood or stress this holiday season."