Clay and de Waal (2013) found that young bonobos offer comfort to recipients of aggression (consolation) more often than adults, and that mother-reared individuals offer consolation more frequently than orphaned individuals, suggesting that rearing history plays an important role in emotional regulation and empathy for others.
You can read more about from De Waal’s post on The Dodo, or in their original paper:
Clay, Z. & de Waal, FBM. (2013). Bonobos respond to distress in others: Consolation across the age spectrum. PLoS ONE 8:1–13.