The Inner Lives of NPC’s – BSc thesis
Title: The Inner Lives of NPC’s
Title in Swedish: NPC:ers inre liv – En kvalitativ studie om NPC:ers upplevda trovärdighet i narrativt drivna spel
Authors: Hannes Lemberg, Tova Wesström
Institution: Stocholm University (SU), Department of Computer and Systems Sciences (DSV), Sweden
Date and language: Spring term 2024, Swedish
Type: Thesis at BSc level degree project 15 HP (sv: Självständigt arbete på grundnivå [kandidatexamen])
Key words: NPC, Believability, Player experience, Story driven games, Interaction
Advisor: Mirjam Palosaari Eladhari
Abstract
The Non-Player Character (NPC) is an autonomous agent and character in a video game that the player can not control herself, but instead is controlled by the computer. Today, artificial intelligence is a widespread tool to develop and control autonomous agents. However, the NPCs are unique since their primary function is not necessarily to be as smart or as sufficient as possible. Instead, the main goal of the NPC is to enhance the player’s experience and can therefore play a key role in creating immersive experiences. Believability and immersion are often described as being closely related to one another and for the majority of story driven games, the goal is to offer an immersive experience for the player. Therefore, believable NPCs could be a significant part for game developers when building immersive experiences and more appealing games. However, the amount of scientific research into what actually makes an NPC believable is limited, and building emotionally intelligent agents, while also being reactive and autonomous, is not an easy feat. Some of the previous research suggests that it’s the portrayal of thoughts and emotions that makes the NPCs believable ̶ they appear to have an inner life.
The purpose of this study is to contribute to a greater understanding of how players experience believability regarding NPC’s in story driven games, with a focus on how the NPCs’ expression of inner thoughts and emotions contributes to increased believability. The findings of the study aim to provide a deeper insight into the relatively narrow research area of believable NPC’s, but the work can also give game developers an enhanced understanding of how they can develop their agents to offer as immersive an experience as possible.
Through semi-structured interviews and thematic analysis, the ten participants in this case study were shown pre-recorded material from three different story driven games, where the NPC design varied between the examples. The thematic analysis showed that there are certain characteristics of NPCs that seem to be of greater importance for perceived believability. The themes selected were “Expression,” “Behavior,” and “Player Influence.” The results showed that believability is a multifaceted issue where players’ own expectations, experiences, and opinions come into play, and therefore, it is not possible to define a clear template to guarantee believability. However, it also emerged that there are some general aspects that affect the degree of believability of NPC’s, where emotional expression and context are two of the most crucial factors. A broad emotional expression that can be expressed in many different ways is important for believability, and the context of the NPC lays the foundation for the player’s expectation of how it should behave. Moreover, several of the aspects that constitute a believable NPC seem to be related to, and to some extent interact with, each other.