Abstracts Category : Other

GLaDOS: Integrating Emotion-Based Behaviours into Non-Player Characters in Computer Role-Playing Games

by Geneva Smith

Non-Player Character (NPC) believability is a game aspect that can be exploited to increase a game's replayability, but little research has been conducted on the topic. One method for enhancing a NPC's believability is to integrate human-like behaviours into their design, so that they react to players in a realistic and interesting way. A large part of human behaviour can be explained by their emotions; therefore it was selected as the inspiration for the GLaDOS system.Two psychological theories of emotion, Lazarus's cognitive appraisal and Plutchik's psycho-evolutionary synthesis, guided the design of the GLaDOS system, although several components are not unique to these theories. An implementation of the design was created as a "mod" for the popular CRPG "The Elder Scrolls V: Skyrim" to test its feasibility within the context of a commercial game. This task required an additional psychological model, PAD space, to map appraisal values to emotion codes and intensities. Feasibility testing was done via a user study to determine if the GLaDOS system increases player engagement when compared to the original game. While the objective analysis found that there were no significant differences between the two versions, subjective participant responses expressed a strong affinity for the GLaDOS system. Since player engagement is inherently subjective, it is encouraging to see positive responses from participants. This indicates that the GLaDOS system, and NPC believability in general, is one aspect of video games that has the potential to increase a game's replayability and should be investigated further. Thesis Master of Applied Science (MASc) Realistic video game characters are a desirable game component to increase a game's value. Even if the game's ending does not change, realistic character behaviours encourage players to replay a game multiple times to see what happens along the way. This is closer to tabletop games where players know the game's outcome, but still play because no two sessions are alike. Despite its advantages, few developments have been made towards realistic game characters. An easily recognizable factor of human decision-making and behaviour is emotion and integrating emotion into character design is one way to improve their realism. The GLaDOS system is a proof-of-concept product that incorporates psychological models of emotion into its design. To test its impact on player engagement, the system was implemented as an extension for the popular computer game "The Elder Scrolls V: Skyrim". Preliminary test results are promising and show that further development could prove fruitful.Advisors/Committee Members: Carette, Jacques, Computing and Software.