A Head Movement Propensity Model for Animating Gaze Shifts and Blinks of Virtual Characters Christopher Peters a , Adam Qureshi b a Coventry University, Coventry, CV1 2TL, West Midlands, UK b The Serious Games Institute, Coventry University Technology Park, Coventry, CV1 2TL, West Midlands, UK Abstract An automatic model is presented for animating gaze shifts of virtual char- acters towards target locations in a virtual environment. Two connected com- ponents are described: an eye-head controller and a blinking controller. The gaze control model is based on results from neuroscience, and dictates the con- tributions of the eyes and head to a gaze shift according to an individual’s head movement propensity; that is, their tendency to recruit their head when making gaze motions under different conditions. The blink controller simulates gaze- evoked blinking, a specific category of behaviours that accompany gaze shifts. The probability of occurrence of such blinks, and their amplitude, is related to the gaze shift. These factors may allow for more believable gaze behaviour, providing variety in animation. The model is of particular significance to seri- ous game environments, where the quality of a character’s gaze behaviour may affect engagement, immersion and learning outcomes. Keywords: Gaze; blinking; virtual characters; serious games 1. Introduction Virtual characters form an integral part of applications featuring virtual en- vironments, from computer entertainment titles to serious games. The purpose of such characters may merely be to contribute to the overall believability of scenes, by being visible as crowds of spectators in the background, or may be more active and prominent, by engaging in close-up interaction with the user, for example during pedagogical situations, as is the case with Embodied Con- versational Agents (see, for example, Greta [6]). Given the wide repertoire of behaviours that a virtual character must be capable of engaging in, one of the most fundamental is the ability to attend to the user and environment in an appropriate manner by orienting the head and eyes to fix the line of sight. As noted in [12], many animals, including horses and rabbits, have eyes in the lateral areas of their heads, removing the need for them to substantially reorient their heads in order to change their line of sight. In contrast, human eyes are set into the front of the skull: given the Email addresses: Christopher.Peters@coventry.ac.uk (Christopher Peters), AQureshi@cad.coventry.ac.uk (Adam Qureshi) Preprint submitted to Computers and Graphics: Serious Games