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.

Artificial Intelligence (AI) is used in many games and quite often the Non-Player Character(NPC)s simulate humans. To make the human NPCs believable and feel alive they need to be as human-like as possible in their behaviour. Three features commonly used to make an NPC human-like are needs, like eating or sleeping, social relationships and personalities. The objective of this thesis was to create an AI with different personalities that the NPCs may have in the game Future Happiness Challenge (FHC) and compare these personalities as well as try to find out whether personalities enhance the game experience. Three different personalities are implemented; Selfish, Selfless and Balanced. These are used as FHC presents the option to play either selfish or selfless. It can be played as a team or as an individualist that does not care about the others. This thesis tries to answer the question whether a player prefers a selfless NPC to a selfish in a game where this option is available. These extremes are also compared to a balanced NPC. When implementing the AI and the personalities, a Behaviour Tree (BT) was used and the main features of this implementation is presented to give an example of how personalities can be implemented in a game like FHC. The results suggest that personalities enhance the game experience and an interesting correlation can be seen between the players preference of an NPC and their own personality when playing the game. Rather than always preferring a selfish or a selfless NPC, the players seem to prefer the NPC which has a personality closely related to their own within the game. / Artificiell intelligens (AI) används i många spel och det är vanligt att datorstyrda karaktärer (Non-Player Characters) föreställer människor. För att göra dessa karaktärer trovärdiga och ge känslan av att leva så behöver deras beteenden göras så mänskliga som möjligt. Tre egenskaper som ofta används för att göra karaktärerna mänskliga är behov, såsom att äta eller sova, sociala relationer och personligheter. Målet med det här arbetet var att skapa en AI med olika personligheter som karaktärerna kan ha i spelet Future Happiness Challenge (FHC) och jämföra dessa personligheter samt försöka ta reda på om personligheter ökar spelupplevelsen. Tre olika personligheter implementerades; självisk, osjälvisk och balanserad. Dessa valdes då FHC ger spelaren möjligheten att spela antingen själviskt eller osjälviskt. Det kan spelas som ett lag eller som en egoist som inte bryr sig om de andra. Denna rapport försöker svara på frågan om spelaren föredrar en osjälvisk karaktär över en självisk i ett spel där denna möjlighet finns. Dessa extrema personligheter jämförs också med en balanserad. Under utvecklingen av AIn och personligheterna användes tekniken Behaviour Tree (BT) och större delen av implementationen är presenterad i detta arbete för att ge ett exempel på hur personligheter kan implementeras i ett spel som FHC. Resultaten föreslår att personligheter ökar spelupplevelsen och ett intressant samband kan ses mellan spelarnas preferens av NPC och spelarnas personligheter i FHC. Istället för att alltid föredra en självisk eller osjälvisk NPC, verkar spelarna föredra den NPC som har en personlighet lik sin egen i spelet.

One of the most important features of a (computer) game that makes it memorable is an ability to bring a sense of engagement. This can be achieved in numerous ways, but the most major part is a challenge, often provided by in-game enemies and their ability to adapt towards the human player. However, adaptability is not very common in games. Throughout this thesis work, aspects of the game control systems that can be improved in order to be adaptable were studied. Based on the results gained from the study of the literature related to artificial intelligence in games, a classification of games was developed for grouping the games by the complexity of the control systems and their ability to adapt different aspects of enemies behavior including individual and group behavior. It appeared that only 33% of the games can not be considered adaptable. This classification was then used to analyze the popularity of games regarding their challenge complexity. Analysis revealed that simple, familiar behavior is more welcomed by players. However, highly adaptable games have got competitively high scores and excellent reviews from game critics and reviewers, proving that adaptability in games deserves further research.

Berättande för Virtual Reality undersöker hur okonventionellt berättande kan påverka en spelares upplevda förhållande till en non-player character i vad som annars är en minimalistisk Virtual Reality-simulation. Studien innefattar en kvalitativ undersökning som utfördes på åtta testpersoner som alla fick spela igenom tre sociala scenarier i Virtual Reality och sedan intervjuas för att utvinna data till undersökningen. För att stödja undersökningens upplägg baserades arbetet på en bred bakgrund relaterad till bland annat berättartekniker och Virtual Reality-utveckling. Resultaten av undersökningen uppmärksammar potentialen som Virtual Reality har för att stärka den emotionella kopplingen mellan en spelare och en non-player character. Det lägger också en grund för vidare experimentering inom berättande i mediet i framtiden.

The connection that players can feel toward their characters in pen-and-paper roleplaying games is a known phenomenon that has been previously studied and is recognized among roleplaying enthusiasts. Pen-and-paper roleplaying games are a complex form of games, with three distinct frames which are ludological, social, and diegetic (also called narrative). The frames are different aspects of the game as well as the base of different motivations for players, who value the frames in a varied degree. The goal of this thesis is to examine if in-game choices based on the diegetic frame in contrast to the ludological frame are correlated with the player/character connection. The method used for data collection is distribution of a quantitative questionnaire on the internet, spread to Swedish roleplayers through social media and associations tied to SVEROK. With their answers, the analysis identifies correlations between the player/character connection and the three frames of pen-and-paper roleplaying games, as well as other correlations noted in the data analysis. The literature revolves around the two core concepts; the player/character connection and the three frames of roleplaying games. The result shows that diegetic choices in contrast to ludological are weakly correlated with the player/character connection.

Brand loyalty in a gaming context takes many forms, including conscious selection of brand, intention of game continuation, positive word of mouth, recommendation, or even active recruitment. As games can be played multiple times, player loyalty is essential to fostering an on-going relationship between brand and consumer. This study focuses on the theory of self-congruity, the congruence between one’s self-concept and one’s perception of a brand’s personality, and its impact on brand loyalty in the gaming industry, a market that has grown exponentially in recent years. Through 31 in-depth interviews, the initial qualitative research explores self-congruity (actual, ideal, social, and ideal social) and its relationship to the gaming environment and how that impacts brand loyalty. The findings of the first study demonstrated: 1. congruity between the player and game character, rather than the game itself, 2. the deeply personal approach to character design, and 3. the feeling of immersion in the game’s narrative. Based on the initial study findings, the second study was developed to incorporate flow theory that describes the nature of feeling fully immersed within the game. A conceptual model was created to integrate self-congruity and flow theories and their impact on brand loyalty. The model was then tested through 512 respondents of a self-reported survey. Results supported prior researchers’ findings, such as the relationships between player-character identification and flow as well as flow and loyalty. Yet, we found that ideal congruity may be a stronger indicator of loyalty as mediated through flow, while actual congruity may in fact inhibit the relationship. The results of this research provide a theoretical contribution by adding self-congruity theory to the flow and loyalty body of knowledge in the gaming space. Furthermore, the self-congruity measurement model provides an alternative measurement method to the previous player-character identification model. From a managerial perspective, the study results support an approach to game design that encourages character design suited to players’ ideal selves rather than mimicking their actual, “real world” selves. / Business Administration/Marketing

The personality traits of NPC characters are key elements in the complex interactions within games. This study, based on the Big Five personality theory, aims to explore how the perceived personality of NPC characters influences player choices. In the initial phase of the experiment, we designed two original NPC characters based on theories such as the Big Five personality model and presented them to the participants through textual stories and visual images. Subsequently, they were given imagined game tasks that we designed, and they had to choose the NPC character they were more inclined towards in each task. Through analysis, we found connections between certain Big Five personality traits of NPC characters and different tasks. We also discovered discrepancies between the intended personality design of the characters and their actual perceived personalities, with variations observed in the exhibited differences of each personality. In conclusion, the perceived personality traits of NPC characters have various influences and connections to player choice behavior.

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Non-Player Character (NPC) behaviors in todays computer games are mostly generated from manually written scripts. The high cost of manually creating complex behaviors for each NPC to exhibit intelligence in response to every situation in the game results in NPCs with repetitive and artificial looking behaviors. The goal of this research is to enable NPCs in computer games to exhibit natural and human-like behaviors in non-combat situations. The quality of these behaviors affects the game experience especially in story-based games, which rely heavily on player-NPC interactions. Reinforcement Learning has been used in this research for BioWare Corp.s Neverwinter Nights to learn natural-looking behaviors for companion NPCs. The proposed method enables NPCs to rapidly learn reasonable behaviors and adapt to the changes in the game environment. This research also provides a learning architecture to divide the NPC behavior into sub-behaviors and sub-tasks called decision domains.

Digital games incorporate systems that allow players to customise and develop their controllable in-game representative (avatar) over the course of a game. Avatar customisation systems represent a point at which the goals and values of players interface with the intentions of the game developer forming a dynamic and complex relationship between system and user. With the proliferation of customisable avatars through digital games and the ongoing monetisation of customisation options through digital content delivery platforms it is important to understand the relationship between player and avatar in order to provide a better user experience and to develop an understanding of the cultural impact of the avatar. Previous research on avatar customisation has focused on the users of virtual worlds and massively multiplayer games, leaving single-player avatar experiences. These past studies have also typically focused on one particular aspect of avatar customisation and those that have looked at all factors involved in avatar customisation have done so with a very small sample. This research has aimed to address this gap in the literature by focusing primarily on avatar customisation features in single-player games, aiming to investigate the relationship between player and customisation systems from the perspective of the players of digital games. To fulfill the research aims and objectives, the qualitative approach of interpretative phenomenological analysis was adopted. Thirty participants were recruited using snowball and purposive sampling (the criteria being that participants had played games featuring customisable avatars) and accounts of their experiences were gathered through semi-structured interviews. Through this research, strategies of avatar customisation were explored in order to demonstrate how people use such systems. The shortcomings in game mechanics and user interfaces were highlighted so that future games can improve the avatar customisation experience.