The tendency to reciprocate can even generalize, so people become more helpful toward others after being helped.
ðə tˈɛndənsi tə ɹᵻsˈɪpɹəkˌeɪt kæn ˈiːvən dʒˈɛnɚɹəlˌaɪz, sˌoʊ pˈiːpəl bɪkˌʌm mˈoːɹ hˈɛlpfəl təwˈɔːɹd ˈʌðɚz ˈæftɚ bˌiːɪŋ hˈɛlpt.