BALANCING ACT: THE EFFECT OF DYNAMIC DIFFICULTY ADJUSTMENT IN COMPETITIVE MULTIPLAYER VIDEO GAMES Alexander Baldwin B. Games & Interactive Entertainment, Honours (IT). Written under the supervision of Assoc. Prof. Daniel Johnson & Assoc. Prof. Peta Wyeth Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy School of Electrical Engineering and Computer Science Faculty of Science and Engineering Queensland University of Technology 2016 Keywords Challenge; Competitive; Dynamic difficulty adjustment; Game design; Intrinsic motivation; Multiplayer; Player balancing; Player experience; Self-determination theory; Video games Balancing Act: The Effect of Dynamic Difficulty Adjustment in Competitive Multiplayer Video Games i Abstract Unbalanced challenge is an issue in video games that can have negative effects on enjoyment and the player experience. Theories of optimal experience such as Flow and intrinsic motivation such as Self-Determination Theory agree that a match between user skill and task difficulty are important for improving the user’s experience. Research into singleplayer games has demonstrated methods such as Dynamic Difficulty Adjustment (DDA) that balance challenge in response to real-time player performance can have a positive effect on the player experience. However, such methods cannot be directly applied to the context of competitive multiplayer games due to the generation of challenge through player vs player conflict. This thesis has investigated the largely unexplored area of Multiplayer Dynamic Difficulty Adjustment (MDDA); game features that attempt to directly manipulate the performance of certain players to balance differently skilled players in a multiplayer match. Through a formal review of MDDA features in existing commercial competitive multiplayer games, a framework of MDDA “instances” was created to allow the classification of differing designs and implementations of MDDA. This was further validated using a combination of interviews and an online survey which gave insight into player values of MDDA as well as highlighting player awareness of MDDA as an area in need of further examination. Two experiments were conducted to test the effect of MDDA designed to assist low-performing players as well as the influence of awareness on performance and the player experience. These revealed MDDA to be effective at balancing performance but its presence not a guarantee of improved experience. However, awareness of MDDA was found to improve aspects of the player experience such as competence and flow and affect the performance of assisted low-performing players. Collectively, these studies have provided a much better understanding of MDDA and awareness with industry-relevant applications and contributions to better inform the design of MDDA for optimal experience. ii Balancing Act: The Effect of Dynamic Difficulty Adjustment in Competitive Multiplayer Video Games Table of Contents Keywords ............................................................................................................ i Abstract ............................................................................................................. ii Table of Contents ............................................................................................. iii List of Figures ................................................................................................ viii List of Tables ..................................................................................................... x List of Abbreviations ...................................................................................... xii List of Publications ........................................................................................ xiii Statement of Original Authorship ................................................................ xiv Acknowledgements ......................................................................................... xv Chapter 1: Introduction ................................................................................ 1 1.1 Background ..........................................................................................................1 1.2 Context .................................................................................................................3 1.3 Purposes................................................................................................................4 1.4 Significance and Scope.........................................................................................4 1.5 Thesis Outline .......................................................................................................6 2 Literature Review .................................................................................... 9 2.1 The State of Video Game Research ......................................................................9 2.2 Flow and Optimal Experience ............................................................................10 2.3 Challenge & Skill ...............................................................................................12 2.4 Singleplayer Challenge Balancing .....................................................................14 2.4.1 Static Challenge Balancing.................................................................................14 2.4.2 Dynamic Difficulty Adjustment .........................................................................15 2.5 Multiplayer Challenge Balancing .......................................................................17 2.5.1 Multiplayer Matchmaking ..................................................................................19 Balancing Act: The Effect of Dynamic Difficulty Adjustment in Competitive Multiplayer Video Games iii 2.5.2 Dynamic Difficulty Adjustment in Multiplayer Gameplay ............................... 20 2.6 Measuring the Player Experience ...................................................................... 24 2.6.1 Survey Method ................................................................................................... 24 2.6.2 Interview Method ............................................................................................... 26 2.6.3 Psychophysiological Measures .......................................................................... 28 2.7 Summary and Implications ................................................................................ 31 3 Research Design ..................................................................................... 33 3.1 Research Structure and Scope ............................................................................ 33 3.2 Research Stages ................................................................................................. 34 3.2.1 STAGE 1 - Defining and Creating a Multiplayer Dynamic Difficulty Adjustment (MDDA) Framework...................................................................... 35 3.2.2 STAGE 2 – Evaluating and Revising the MDDA Framework .......................... 35 3.2.3 STAGE 3 – Investigating the Effect of MDDA ................................................. 37 3.2.4 STAGE 4 – Investigating Optimal Awareness of MDDA ................................. 44 3.2.5 Research Stage Methodology Summary ............................................................ 48 3.3 Ethics and Limitations ....................................................................................... 49 4 STAGE 1 - Defining and Creating an MDDA Framework ............... 51 4.1 Introduction ........................................................................................................ 51 4.1.1 Defining Multiplayer Dynamic Difficulty Adjustment (MDDA) ...................... 51 4.2 Method ............................................................................................................... 52 4.2.1 Game Selection Method ..................................................................................... 52 4.2.2 MDDA Instance Analysis .................................................................................. 54 4.3 Results - Preliminary MDDA Framework (v1) ................................................. 58 4.3.1 Overview ............................................................................................................ 58 4.3.2 Framework Chart ............................................................................................... 58 4.3.3 Framework Definitions ...................................................................................... 59 4.3.4 Example MDDA Instances Described Using Framework ................................. 64 4.4 Discussion .......................................................................................................... 67 iv Balancing Act: The Effect of Dynamic Difficulty Adjustment in Competitive Multiplayer Video Games 4.5 Stage 1 Summary ................................................................................................67 5 STAGE 2 – Evaluating and Revising the MDDA Framework ......... 69 5.1 Introduction ........................................................................................................69 5.2 Method................................................................................................................70 5.2.1 Interview Method ...............................................................................................70 5.2.2 Survey Method ...................................................................................................73