Research on user experience of the video game difficulty based on flow theory and fNIRS

Difficulty balance in the game level design is particularly important for user experience (UX). This study uses cognitive control and flow theory as a starting point, and based on the functional near-infrared spectroscopy technology, this research obtained oxygenated hemoglobin concentration (Delta HbO(2)) signals from three brain areas in the prefrontal cortex (PFC), namely the dorsolateral prefrontal cortex (DLPFC), the ventral prefrontal cortex (VLPFC), and the frontal area (FPA). Combined with the subjective flow state scale to explore the reaction difference between the video game players (VGPs) and the non-video game players (NVGPs) during the entire period of playing video games and the moment of game difficulty changes. The results show that VGPs and NVGPs have significant differences between flow state and HbO(2) signals in different brain regions of the PFC. The players' flow state is affected by the game difficulty. The HbO(2) signals in the players' DLPFC and FPA have a linear dependence relation with the flow state. This research proves that VGPs and NVGPs have different UX with game difficulty changes from the cognitive perspective. The results provide a reference for the future game level design about game difficulty balance to achieve a better UX in the game.