(Original broadcast date: May 26, 2017). Helping others feels good, but why do some go farther than others? This hour, TED speakers explore ideas about altruism — what motivates us to be altruistic, what limits us and do we ever go too far. TED speakers include psychologist Abigail Marsh, clinical psychologist Cheryl Steed, philosopher Peter Singer, and writer Larissa MacFarquhar.