Toward open-microphone engagement for multiparty interactions

There currently is considerable interest in developing new open-microphone engagement techniques for speech and multimodal interfaces that perform robustly in complex mobile and multiparty field environments. State-of-the-art audio-visual open-microphone engagement systems aim to eliminate the need for explicit user engagement by processing more implicit cues that a user is addressing the system, which results in lower cognitive load for the user. This is an especially important consideration for mobile and educational interfaces due to the higher load required by explicit system engagement. In the present research, longitudinal data were collected with six triads of high-school students who engaged in peer tutoring on math problems with the aid of a simulated computer assistant. Results revealed that amplitude was 3.25dB higher when users addressed a computer rather than human peer when no lexical marker of intended interlocutor was present, and 2.4dB higher for all data. These basic results were replicated for both matched and adjacent utterances to computer versus human partners. With respect to dialogue style, speakers did not direct a higher ratio of commands to the computer, although such dialogue differences have been assumed in prior work. Results of this research reveal that amplitude is a powerful cue marking a speaker's intended addressee, which should be leveraged to design more effective microphone engagement during computer-assisted multiparty interactions.