Baby Ears: a recognition system for affective vocalizations

We collected more than 500 utterances from adults talking to their infants. We automatically classified 65% of the strongest utterances correctly as approval, attentional bids, or prohibition. We used several pitch and formant measures, and a multidimensional Gaussian mixture-model discriminator to perform this task. As previous studies have shown, changes in pitch are an important cue for affective messages; we found that timbre or cepstral coefficients are also important. The utterances of female speakers, in this test, were easier to classify than were those of male speakers. We hope this research will allow us to build machines that sense the “emotional state” of a user