A Control-Theoretic Approach to Adaptive Physiological Games

We present an adaptive biofeedback game that aims to maintain the player's arousal level by monitoring physiological signals. We use concepts from control theory to model the interaction between human physiology and game difficulty during game play. We validate the approach on a car-racing game with real-time adaptive game mechanics. Specifically, we use car speed, road visibility, and steering jitter as three mechanisms to manipulate game difficulty. We propose quantitative measures to characterize the effectiveness of these game adaptations in manipulating the player's arousal. For this purpose, we use electro dermal activity (EDA) as a physiological correlate of arousal. Experimental trials with 20 subjects in both open-loop (no feedback) and closed-loop (negative feedback) conditions show statistically significant differences among the three game mechanics in terms of their effectiveness. Specifically, manipulating car speed provides higher arousal levels than changing road visibility or vehicle steering. Finally, we discuss the theoretical and practical implications of our approach.