In the study, researchers looked at 681 adolescents, 11-14 years old, in two U.S. cities. They tracked them for four different time points, starting in 2008 through 2011. The participants responded to 10 statements such as "I feel useless at times" or "I am satisfied with myself" to assess self-esteem. Prosocial behavior was measured by self-reports, looking at various aspects of kindness and generosity, such as "I help people I don't know, even if it's not easy for me" or "I go out of my way to cheer up my friends" or "I really enjoy doing small favors for my family." "A unique feature of this study is that it explores helping behaviors toward multiple different targets," Padilla-Walker said. "Not all helping is created equal, and we're finding that prosocial behavior toward strangers is protective in a variety of ways that is unique from other types of helping. Another important finding is that the link between prosocial behavior and self-esteem is over a one-year time period and present across all three age lags in our study. Though not an overly large effect, this suggests a stable link between helping and feeling better about oneself across the early adolescent years." - www.sciencedaily.com