It may also signal interactive and cooperative intentions, since someone who does not expect to interact further in the future gains nothing from such costly signaling.
ɪt mˈeɪ ˈɔːlsoʊ sˈɪɡnəl ˌɪntɚɹˈæktɪv ænd koʊˈɑːpɚɹətˌɪv ɪntˈɛnʃənz, sˈɪns sˈʌmwʌn hˌuː dʌznˌɑːt ɛkspˈɛkt tʊ ˌɪntɚɹˈækt fˈɜːðɚɹ ɪnðə fjˈuːtʃɚ ɡˈeɪnz nˈʌθɪŋ fɹʌm sˈʌtʃ kˈɔstli sˈɪɡnəlɪŋ.