Evaluating Player Stress and Motivation Through Biofeedback-Controlled Dynamic Difficulty Adjustment

This study researches the effects of a biofeedback-based Dynamic Difficulty Adjustment (DDA) system on player stress management in a survival-horror video game. For this purpose, a game titled Code: Terror was developed, in which players’ psychophysiological data—such as heart rate, stress level, and voice level—were collected in real time through a smartwatch. Based on these data, game parameters were dynamically adjusted. The adaptation process was guided by the “Relax-to-win” model, which aims to make the game easier as players remain calm, using their level of relaxation as a baseline. A total of 40 participants were recruited and divided into two reciprocal groups: one group experienced the game solely with the DDA system activated, while the other played first with the DDA system disabled and then with it enabled. Player experience was evaluated using the Intrinsic Motivation Inventory (IMI) and the Challenge Originating from Recent Gameplay Interaction Scale (CORGIS). Results showed that the dynamic biofeedback system significantly enhanced intrinsic motivation and perceived challenge, while also reducing physiological arousal, indicating its effectiveness in promoting emotional regulation—the inclusion of both gameplay conditions for participants allowed for the collection of more consistent and meaningful data. The results suggest that biofeedback-driven DDA systems have the potential to enrich player experience both emotionally and motivationally. Furthermore, the findings highlight the potential of such adaptive biofeedback mechanisms to serve as intelligent medical decision support tools for stress management, mental health monitoring, and personalized intervention strategies.