Recognizing the intention of others is important in all social interactions, especially in the service domain. Enabling a bartending robot to serve customers is particularly challenging as the system has to recognize the social signals produced by customers and respond appropriately. Detecting whether a customer would like to order is essential for the service encounter to succeed. This detection is particularly challenging in a noisy environment with multiple customers. Thus, a bartending robot has to be able to distinguish between customers intending to order, chatting with friends or just passing by. In order to study which signals customers use to initiate a service interaction in a bar, we recorded real-life customer-staff interactions in several German bars. These recordings were used to generate initial hypotheses about the signals customers produce when bidding for the attention of bar staff. Two experiments using snapshots and short video sequences then tested the validity of these hypothesized candidate signals. The results revealed that bar staff responded to a set of two non-verbal signals: first, customers position themselves directly at the bar counter and, secondly, they look at a member of staff. Both signals were necessary and, when occurring together, sufficient. The participants also showed a strong agreement about when these cues occurred in the videos. Finally, a signal detection analysis revealed that ignoring a potential order is deemed worse than erroneously inviting customers to order. We conclude that (a) these two easily recognizable actions are sufficient for recognizing the intention of customers to initiate a service interaction, but other actions such as gestures and speech were not necessary, and (b) the use of reaction time experiments using natural materials is feasible and provides ecologically valid results.
Keywords: human robot interaction, social signal processing, intention recognition, social robotics, social signaling, action recognition
Citation: Loth S, Huth K and De Ruiter JP (2013) Automatic detection of service initiation signals used in bars. Front. Psychol. 4:557. doi: 10.3389/fpsyg.2013.00557
Received: 01 June 2013; Accepted: 06 August 2013;
Published online: 30 August 2013.
Edited by:Serge Thill, University of Skövde, Sweden
Reviewed by:Anna M. Borghi, University of Bologna and Institute of Cognitive Sciences and Technologies, Italy
Copyright © 2013 Loth, Huth and De Ruiter. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Sebastian Loth, Faculty for Linguistics and Literary Studies, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany e-mail: firstname.lastname@example.org