Signaling and detecting uncertainty in audiovisual speech by children and adults

We describe two experiments on signaling and detecting uncertainty in audiovisual speech by adults and children. In the first study, utterances from adult speakers and child speakers (aged 7-8) were elicitated and annotated with a set of six audiovisual features. It was found that when adult speakers are uncertain about their answer they are more likely to produce filled pauses, delays, high intonation, eyebrow movements, smiles and funny faces. The basic picture for the child speakers is similar, in that the presence of an audiovisual cue in an answer correlates with uncertainty, but the differences are relatively small and only significant for the features delay, eyebrow and funny face. In the second study both adult and child judges watched answers from adult and child speakers selected from the first study to find out whether they were able to correctly estimate a speakers’ level of uncertainty. It was found that both child and adult judges give more accurate scores for answers from adult speakers than from child speakers and that child judges overall provide less accurate scores than adult judges.