Thus, while altruistic persons may under some circumstances be outcompeted by less altruistic persons at the individual level, according to group selection theory, the opposite may occur at the group level where groups consisting of the more altruistic persons may outcompete groups consisting of the less altruistic persons.
ðˈʌs, wˌaɪl ˌɔːltɹuːˈɪstɪk pˈɜːsənz mˈeɪ ˌʌndɚ sˌʌm sˈɜːkəmstˌænsᵻz biː aʊtkəmpˈiːɾɪd baɪ lˈɛs ˌɔːltɹuːˈɪstɪk pˈɜːsənz æt ðɪ ˌɪndᵻvˈɪdʒuːəl lˈɛvəl, ɐkˈoːɹdɪŋ tə ɡɹˈuːp sᵻlˈɛkʃən θˈiəɹi, ðɪ ˈɑːpəzˌɪt mˈeɪ əkˈɜːɹ æt ðə ɡɹˈuːp lˈɛvəl wˌɛɹ ɡɹˈuːps kənsˈɪstɪŋ ʌvðə mˈoːɹ ˌɔːltɹuːˈɪstɪk pˈɜːsənz mˈeɪ aʊtkəmpˈiːt ɡɹˈuːps kənsˈɪstɪŋ ʌvðə lˈɛs ˌɔːltɹuːˈɪstɪk pˈɜːsənz.