Abstract
Artificial listeners are virtual agents that can listen attentively to a human speaker in a dialog. In this paper, we present two experiments where we investigate the perception of rule-based backchannel strategies for artificial listeners. In both, we collect subjective judgements of humans who observe a video of a speaker together with a corresponding animation of an artificial listener. In the first experiment, we evaluate six rule-based strategies that differ in the types of features (e.g. prosody, gaze) they consider. The ratings are given at the level of a speech turn and can be considered a measure for how human-like the generated listening behavior is perceived. In the second experiment, we systematically investigate the effect of the quantity, type and timing of backchannels within the discourse of the speaker. Additionally, we asked human observers to press a button whenever they thought a generated backchannel occurrence was inappropriate. Both experiments together give insights in the factors, both from an observation and generation point-of-view, that influence the perception of backchannel strategies for artificial listeners.
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Bavelas, J. B., Coates, L., & Johnson, T. (2000). Listeners as co-narrators. Journal of Personality and Social Psychology, 79(6), 941–952.
Bavelas, J. B., Coates, L., & Johnson, T. (2002). Listener responses as a collaborative process: The role of gaze. Journal of Communication, 52(3), 566–580.
Bertrand, R., Ferré, G., Blache, P., Espesser, R., & Rauzy, S. (2007). Backchannels revisited from a multimodal perspective. Proceedings of Auditory-Visual Speech Processing (pp. 1–5). Hilvarenbeek, The Netherlands.
Bevacqua, E., Pammi, S., Hyniewska, S.J., Schröder, M., & Pelachaud, C. (2010). Multimodal backchannels for embodied conversational agents. Proceedings of the International Conference on Interactive Virtual Agents (IVA) (pp. 194–200). Philadelphia.
Boersma, P., & Weenink, D. (2009). Praat: Doing phonetics by computer. Software. www.praat.org.
Brunner, L. J. (1979). Smiles can be back channels. Journal of Personality and Social Psychology, 37(5), 728–734.
Cathcart, N., Carletta, J., & Klein, E. (2003). A shallow model of backchannel continuers in spoken dialogue. Proceedings of the Conference of the European chapter of the Association for Computational Linguistics, vol. 1 (pp. 51–58). Budapest, Hungary.
de Kok, I., Ozkan, D., Heylen, D., & Morency, L.P. (2010). Learning and evaluating response prediction models using parallel listener consensus. Proceeding of International Conference on Multimodal Interfaces and the Workshop on Machine Learning for Multimodal Interaction (ICMI-MLMI) (p. A3). Beijing, China.
de Kok, I., Poppe, R., & Heylen, D. (2012) Iterative perceptual learning for social behavior synthesis. Technical Report TR-CTIT-12-01, Enschede.
Dittmann, A. T., & Llewellyn, L. G. (1967). The phonemic clause as a unit of speech decoding. Journal of Personality and Social Psychology, 6(3), 341–349.
Dittmann, A. T., & Llewellyn, L. G. (1968). Relationship between vocalizations and head nods as listener responses. Journal of Personality and Social Psychology, 9(1), 79–84.
Duncan, S, Jr. (1972). Some signals and rules for taking speaking turns in conversations. Journal of Personality and Social Psychology, 23(2), 283–292.
Duncan, S, Jr. (1974). On the structure of speaker-auditor interaction during speaking turns. Language in Society, 3(2), 161–180.
Granström, B., House, D., & Swerts, M. (2002). Multimodal feedback cues in human-machine interactions. Proceedings of the International Conference on Speech Prosody (pp. 11–14). Aix-en-Provence, France.
Gratch, J., Okhmatovskaia, A., Lamothe, F., Marsella, S., Morales, M., van der Werf, R.J., & Morency, L.P. (2006). Virtual rapport. Proceedings of the International Conference on Interactive Virtual Agents (IVA) (pp. 14–27). Marina del Rey, CA.
Gravano, A., & Hirschberg, J. (2009). Backchannel-inviting cues in task-oriented dialogue. Proceedings of Interspeech (pp. 1019–1022). Brighton, UK.
Heylen, D., Bevacqua, E., Pelachaud, C., Poggi, I., Gratch, J., & Schröder, M. (2011). Generating Listening Behaviour (Part 4). In: Emotion-oriented systems cognitive technologies, (pp. 321–347) Springer.
Huang, L., Morency, L.P., & Gratch, J. (2010). Learning backchannel prediction model from parasocial consensus sampling: A subjective evaluation. Proceedings of the International Conference on Interactive Virtual Agents (IVA) (pp. 159–172). Philadelphia, PA.
Huang, L., Morency, L.P., & Gratch, J. (2011). Virtual rapport 2.0. Proceedings of the International Conference on Interactive Virtual Agents (IVA) (pp. 68–79). Reykjavik, Iceland.
Jonsdottir, G.R., Gratch, J., Fast, E., & Thórisson, K.R. (2007). Fluid semantic back-channel feedback in dialogue: Challenges and progress. Proceedings of the International Conference on Interactive Virtual Agents (IVA) (pp. 154–160). Paris, France.
Kendon, A. (1967). Some functions of gaze direction in social interaction. Acta Psychologica, 26(1), 22–63.
Kitaoka, N., Takeuchi, M., Nishimura, R., & Nakagawa, S. (2005). Response timing detection using prosodic and linguistic information for human-friendly spoken dialog systems. Transactions of the Japanese Society for Artificial Intelligence, 20(3), 220–228.
Koiso, H., Horiuchi, Y., Tutiya, S., Ichikawa, A., & Den, Y. (1998). An analysis of turn-taking and backchannels based on prosodic and syntactic features in Japanese map task dialogs. Language and Speech, 41(3–4), 295–321.
Maatman, M., Gratch, J., & Marsella, S. (2005). Natural behavior of a listening agent. Proceedings of the International Conference on Interactive Virtual Agents (IVA) (pp. 25–36). Kos, Greece.
Morency, L. P., de Kok, I., & Gratch, J. (2010). A probabilistic multimodal approach for predicting listener backchannels. Autonomous Agents and Multi-Agent Systems, 20(1), 80–84.
Noguchi, H., & Den, Y. (1998). Prosody-based detection of the context of backchannel responses. Proceedings of the International Conference on Spoken Language Processing (ICSLP) (pp. 487–490). Sydney, Australia.
Okato, Y., Kato, K., Yamamoto, M., & Itahashi, S. (1996) Insertion of interjectory response based on prosodic information. Proceedings of the IEEE Workshop Interactive Voice Technology for Telecommunication Applications (pp. 85–88). Basking Ridge, NJ.
Poppe, R., ter Maat, M., & Heylen, D. (2012). Online behavior evaluation with the switching wizard of oz. Proceedings of the International Conference on Interactive Virtual Agents (IVA) (pp. 486–488). Santa Cruz, CA.
Poppe, R., Truong, K.P., & Heylen, D. (2011). Backchannels: Quantity, type and timing matters. Proceedings of the International Conference on Interactive Virtual Agents (IVA) (pp. 228–239). Reykjavik, Iceland.
Poppe, R., Truong, K.P., Reidsma, D., & Heylen, D. (2010). Backchannel strategies for artificial listeners. Proceedings of the International Conference on Interactive Virtual Agents (IVA) (pp. 146–158). Philadelphia, PA
Truong, K.P., Poppe, R., & Heylen, D. (2010). A rule-based backchannel prediction model using pitch and pause information. Proceedings of Interspeech (pp. 490–493). Makuhari, Japan.
Truong, K.P., Poppe, R., de Kok, I., & Heylen, D. (2011). A multimodal analysis of vocal and visual backchannels in spontaneous dialogs. Proceedings of Interspeech (pp. 2973–2976). Florence, Italy.
Valstar, M.F., McKeown, G., Cowie, R., & Pantic, M. (2010). The Semaine corpus of emotionally coloured character interactions. Proceedings of the International Conference on Multimedia & Expo (pp. 1079–1084). Singapore, Singapore.
Van Welbergen, H., Reidsma, D., Ruttkay, Z., & Zwiers, J. (2010). Elckerlyc: A BML realizer for continuous, multimodal interaction with a virtual human. Journal of Multimodal User Interfaces, 3(4), 271–284.
Ward, N., & Tsukahara, W. (2000). Prosodic features which cue back-channel responses in English and Japanese. Journal of Pragmatics, 32(8), 1177–1207.
Xudong, D. (2009). Listener response. In: The pragmatics of interaction (pp. 104–124). Amsterdam: John Benjamins Publishing.
Yngve, V.H. (1970). On getting a word in edgewise. In: Papers from the Sixth Regional Meeting of Chicago Linguistic Society, pp. 567–577. Chicago Linguistic Society.
Acknowledgments
The authors would like to thank Dennis Reidsma for his assistance in preparing the stimuli, and Iwan de Kok for interesting discussions.
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Poppe, R., Truong, K.P. & Heylen, D. Perceptual evaluation of backchannel strategies for artificial listeners. Auton Agent Multi-Agent Syst 27, 235–253 (2013). https://doi.org/10.1007/s10458-013-9219-z
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DOI: https://doi.org/10.1007/s10458-013-9219-z