One is that people will be more helpful when they know that their helping behavior will be communicated to people they will interact with later, publicly announced, discussed, or observed by someone else.
wˈʌn ɪz ðæt pˈiːpəl wɪl biː mˈoːɹ hˈɛlpfəl wɛn ðeɪ nˈoʊ ðæt ðɛɹ hˈɛlpɪŋ bᵻhˈeɪvjɚ wɪl biː kəmjˈuːnᵻkˌeɪɾᵻd tə pˈiːpəl ðeɪ wɪl ˌɪntɚɹˈækt wɪð lˈeɪɾɚ, pˈʌblɪkli ɐnˈaʊnst, dɪskˈʌst, ɔːɹ əbzˈɜːvd baɪ sˈʌmwʌn ˈɛls.