Received: 10 December 2019 Revised: 15 March 2020 Accepted: 23 April 2020 DOI: 10.1002/cav.1928 RESEARCH ARTICLE Immersive walking in a virtual crowd: The effects of the density, speed, and direction of a virtual crowd on human movement behavior Alexandros Koilias 1 Michael G. Nelson 2 Christos-Nikolaos Anagnostopoulos 1 Christos Mousas 2 1 Department of Cultural Technology and Communication, University of the Aegean, Mytilene, Greece 2 Department of Computer Graphics Technology, Purdue University, West Lafayette, Indiana, Correspondence Christos Mousas, Department of Computer Graphics Technology, Purdue University, West Lafayette, IN 47907. Email: cmousas@purdue.edu Abstract We investigated the movement behavior of participants walking within a vir- tual crowd in an immersive virtual environment. We investigated three different parameters that characterize a moving virtual crowd: density, speed, and direc- tion. An immersive road-crossing scenario that took place in a virtual metropoli- tan city was created. In this scenario, the participants were instructed to walk toward the opposite sidewalk. Three measurements (speed, deviation, and tra- jectory length) were used to evaluate the impact of the parameters assigned to the virtual crowd on the movement behavior of the participants. Significant results were found for both the main and interaction effects. The results suggested that the high density, low speed, and diagonal direction situations associated with the virtual crowd had the greatest impacts on the speed, deviation, and trajec- tory lengths of participants when they walked in a virtual environment and were surrounded by a moving virtual population. KEYWORDS human–crowd interaction, movement behavior, virtual crosswalk, virtual crowd, virtual reality 1 INTRODUCTION A number of real-world human–crowd interactions and experiences can be transferred to virtual ones. 1 For example, one might want to virtually travel to a metropolitan city and take a walk on a sidewalk to explore the surroundings. During this experience, the users of such an application might be surrounded by a virtual population. Similarly, users could learn how to evacuate a building while surrounded by a crowd when immersed in a virtual environment. Finally, in a digital film pro- duction, the actor might be asked to walk with a virtual crowd while performing a part of the script. In all the above exam- ples, it is quite likely that the users of such virtual reality experiences might be surrounded by virtual populations that are moving in the same or different directions and most likely doing so at different speeds and with varying levels of density. Although a significant amount of research has been conducted on the analysis, modeling, and simulation of crowds and crowd dynamics, 2-9 and a number of published articles have examined interactions with individual and groups of virtual characters, a limited number of studies have examined how humans walk along with virtual crowd populations surrounding them. 10,11 Therefore, there are no conclusive results regarding whether a moving virtual crowd population affects the movement behavior of humans or how such an effect would materialize. 12,13 Consequently, an understanding of how a moving virtual crowd might or might not affect the movement behavior of humans could be beneficial for Comp Anim Virtual Worlds. 2020;e1928. wileyonlinelibrary.com/journal/cav © 2020 John Wiley & Sons, Ltd. 1 of 14 https://doi.org/10.1002/cav.1928