Intrinsic motivation is when one does something because of personal interest in that particular thing.
ɪntɹˈɪnsɪk mˌoʊɾɪvˈeɪʃən ɪz wɛn wˈʌn dˈʌz sˈʌmθɪŋ bɪkˈʌz ʌv pˈɜːsənəl ˈɪntɹɛst ɪn ðæt pɚtˈɪkjʊlɚ θˈɪŋ.