" In subsequent studies, Warneken and Tomasello found that children were willing to help even when doing so involved hardship and interrupting their play.
Interestingly, they also found that rewarding the children was counterproductive. The children who were rewarded for helping were later less likely to help than those who had never been rewarded. Studies also show that infants as young as six months demonstrate clear preference for toys that enact helping behavior rather than hindering. "

― Thupten Jinpa , A Fearless Heart: How the Courage to Be Compassionate Can Transform Our Lives