Background. Electrodermal activity (EDA) is a method to measure variations in the electrical conductivity of the skin, and it is often used to help assess emotions like anxiety, or stress. However, it is not yet commonly used in video games, although emotions are an essential aspect to consider when developing a game.

Objectives. By using EDA data and a questionnaire, the thesis aims to study the effect of darkness on the participant's skin conductance responses (SCR) and their potential correlation with negative emotions.

Methods. Using the Shimmer3 GSR+ sensor and the Tobii Pro Lab software to measure and record the EDA data and handle the game, a within-participants experiment with 17 participants was conducted. Each participant played one daytime scene and one nighttime scene from the same game. During the experiment, the participant's EDA data was recorded by the Tobii Pro Lab software when the participant played the game. When the games were finished, the participant answered a questionnaire. The questionnaire presented multiple questions regarding their game experience based on negative emotions.

Results. The EDA data point towards a rise in skin conductance responses (SCR) when playing the nighttime game compared to the daytime game. While the questionnaire data points towards a higher prominence of negative emotions during the nighttime game as well. Based on these results, playing the nighttime game made a majority of the participants experience a higher grade of reported negative emotions.

Conclusions. The results suggest that darkness affects both SCR and negative emotions. Meaning that humans have a tendency to react in an emotionally negative way, and have a higher degree of measurable responses in the skin, to a dark environment.