In this paper, we study the effect of instructional priming on postural responses to virtual crowds using a headset-based virtual reality (VR) platform. Specifically, we instruct VR participants that one of the virtual agents in a simulated crowd represents the movement of a real person, and reinforce this instruction by having a single role player present in the experimental arena. Our results show that while VR participants who were primed did not move significantly more when three-dimensional movement was considered, they exhibit significantly more movement in the direction perpendicular to the crowd flow indicating possible collision avoidance maneuvers. These results indicate that manipulation of instructions to participants with the intent of impacting pre-exposure expectations may be used to increase engagement with virtual crowds.