24 Design of Hesitation Gestures for Nonverbal Human-Robot Negotiation of Conflicts AJUNG MOON, McGill University, Canada MANEEZHAY HASHMI and H. F. MACHIEL VAN DER LOOS, University of British Columbia, Canada ELIZABETH A. CROFT, Monash University, Australia AUDE BILLARD, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland When the question of who should get access to a communal resource frst is uncertain, people often negotiate via nonverbal communication to resolve the confict. What should a robot be programmed to do when such conficts arise in Human-Robot Interaction? The answer to this question varies depending on the context of the situation. Learning from how humans use hesitation gestures to negotiate a solution in such con- fict situations, we present a human-inspired design of nonverbal hesitation gestures that can be used for Human-Robot Negotiation. We extracted characteristic features of such negotiative hesitations humans use, and subsequently designed a trajectory generator (Negotiative Hesitation Generator) that can re-create the features in robot responses to conficts. Our human-subjects experiment demonstrates the efcacy of the de- signed robot behaviour against non-negotiative stopping behaviour of a robot. With positive results from our human-robot interaction experiment, we provide a validated trajectory generator with which one can explore the dynamics of human-robot nonverbal negotiation of resource conficts. CCS Concepts: • Human-centered computing → Collaborative interaction; Additional Key Words and Phrases: Human-robot interaction, negotiation, hesitation, nonverbal communication ACM Reference format: Ajung Moon, Maneezhay Hashmi, H. F. Machiel Van der Loos, Elizabeth A. Croft, and Aude Billard. 2021. Design of Hesitation Gestures for Nonverbal Human-Robot Negotiation of Conficts. ACM Trans. Hum.-Robot Interact. 10, 3, Article 24 (July 2021), 25 pages. https://doi.org/10.1145/3418302 1 INTRODUCTION In many everyday activities, it is common for interacting individuals to experience conficts regard- ing priority to access shared resources. When the question of who should get access to the resource This work has been supported by Natural Sciences and Engineering Council, Canada, and the EU project AlterEgo under Grant Agreement No. 600010. Authors’ addresses: A. Moon, Dept. of Electrical and Computer Engineering, McConnell Engineering Building, 3480 Uni- versity Street, Room 541, Montreal, QC, Canada H3A 0E9; email: ajung.moon@mcgill.ca; M. Hashmi and H. F. M. Van der Loos, Dept. of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Science Lane, Vancouver BC, Canada V6T 1Z4; emails: maneezhay@gmail.com, vdl@mech.ubc.ca; E. A. Croft, Faculty of Engineering, Room 107, 14 Alliance Lane, Monash University, Clayton Victoria 3800 Australia; email: elizabeth.croft@monash.edu; A. Billard, Learn- ing Algorithms and Systems Laboratory, EPFL STI I2S LASA ME A3 393 (Bâtiment ME), Station n º9 CH-1015 Lausanne, Switzerland; email: aude.billard@epf.ch. This work is licensed under a Creative Commons Attribution International 4.0 License. © 2021 Copyright held by the owner/author(s). 2573-9522/2021/07-ART24 https://doi.org/10.1145/3418302 ACM Transactions on Human-Robot Interaction, Vol. 10, No. 3, Article 24. Publication date: July 2021.