Capturing User Emotions in Interactive Stories - Comparing a Diegetic and a Non-diegetic Approach to Self-reporting Emotion.

Capturing the player's emotions in an interactive story can serve many purposes, such as to understand player response to a story or to alter the story's path. The concept of diegesis defines the boundary between the story world and the real world, and has been used to explore different ways of conceptualizing user interface (UI) elements in interactive media. This paper explores methods of capturing players' emotions during an interactive story and the concept of diegesis. Specifically, we posit that whether emotion capture exists in a diegetic versus a nondiegetic space can affect its accuracy when capturing player emotion. We developed two interactive stories with two emotion capture methods, one using a diegetic approach, and the other using a non-diegetic approach. We conducted a study with 64 participants to compare the two emotion capture approaches. Our results show that a diegetic approach leads to a better story experience, but that a non-diegetic approach leads to the player's emotion being captured more accurately. We discuss the implications of the study results for integrating emotion capture in the design of interactive stories.