Physiological sensing has been a prominent fixture in games user research (GUR) since the late 1990s, when researchers started to explore its potential to enhance and understand experience within digital game play. Since these early days, is has been widely argued that "affective gaming"---in which gameplay is influenced by a player's emotional state---can enhance player experience by integrating physiological sensors into play. Reflecting in 2020 on these last 20 years of progress, we systematically review the field of affective gaming to answer whether or not it has met this promise. We create a framework (the affective game loop) to classify 162 publications (included from an initial search set of 52,834 results) within affective gaming, present findings on the current state of the field, and discuss how our findings, contextualized within the affective game loop, can guide the future of affective gaming.

"Let's Get Physiological, Physiological!": A Systematic Review of Affective Gaming

In this paper, we consider the use of wearable sensors for providing affect-based adaptation in Ambient Intelligence (AmI) systems. We begin with discussion of selected issues regarding the applications of affective computing techniques. We describe our experiments for affect change detection with a range of wearable devices, such as wristbands and the BITalino platform, and discuss an original software solution, which we developed for this purpose. Furthermore, as a test-bed application for our work, we selected computer games. We discuss the state-of-the-art in affect-based adaptation in games, described in terms of the so-called affective loop. We present our original proposal of a conceptual design framework for games, called the affective game design patterns. As a proof-of-concept realization of this approach, we discuss some original game prototypes, which we have developed, involving emotion-based control and adaptation. Finally, we comment on a software framework, that we have previously developed, for context-aware systems which uses human emotional contexts. This framework provides means for implementing adaptive systems using mobile devices with wearable sensors.

https://www.mdpi.com/1424-8220/19/11/2509/pdf

Analysis and use of the emotional context with wearable devices for games and intelligent assistants

To understand the impact of emotionally driven games on player experience, we developed a procedural horror game (Vanish) capable of run-time level, asset, and event generation. Vanish was augmented to interpret players’ physiological data as a simplified emotional state, mapping it to a set of adaptation rules that modify the player experience. To explore the effects of adaptation mechanisms on player experience, we conducted a mixed-methods study on three different versions of the game, two of which integrated varying biofeedback mechanisms. Players’ affective experiences were objectively measured by analysing physiological data. Additionally, subjective experience was recorded through the use of the Game Experience Questionnaire. Our study confirmed that biofeedback functionality had a statistically significant effect on the ratings of player experience dimensions: immersion, tension, positive affect, and negative affect. Furthermore, participants reported noticeable differences in player experience, favouring the added depth present in the biofeedback-enabled iterations of the game. In the future, these conclusions will help to develop more immersive and engaging player experiences.

Vanishing scares: biofeedback modulation of affective player experiences in a procedural horror game

Research has shown that dynamic difficulty adjustment (DDA) can benefit player experience in digital games. However, in some cases it can be difficult to assess when adjustments are necessary. In this paper, we propose an approach of emotion-based DDA that uses self-reported emotions to inform when an adaptation is necessary. In comparison to earlier DDA techniques based on affect, we use parameterized difficulty to define difficulty levels and select the suitable level based on players' frustration and boredom. We conducted a user study with 66 participants investigating performance and effects on player experience and perceived competence of this approach. The study further explored how self-reports of emotional state can be integrated in dialogs with non-player characters to provide less interruption. The results show that our emotion-based DDA approach works as intended and yields better player experience than constant or increasing difficulty approaches. While the dialog-based self-reports did not positively affect player experience, they yielded high accuracy. Together, these findings indicate our emotion-based approach works as intended and provides good player experience, thus representing a useful tool for game developers to easily implement reliable DDA.

Emotion-based Dynamic Difficulty Adjustment Using Parameterized Difficulty and Self-Reports of Emotion

Chapter 6 Biometrics in Gaming and Entertainment Technologies

Innovations in computer game interfaces continue to enhance the experience of players. Affective games — those that adapt or incorporate a player's emotional state — have shown promise in creating exciting and engaging user experiences. However, a dearth of systematic exploration into what types of game elements should adapt to affective state leaves game designers with little guidance on how to incorporate affect into their games. We created an affective game engine, using it to deploy a design probe into how adapting the player's abilities, the enemy's abilities, or variables in the environment affects player performance and experience. Our results suggest that affectively adapting games can increase player arousal. Furthermore, we suggest that reducing challenge by adapting non-player characters is a worse design choice than giving players the tools that they need (through enhancing player abilities or a supportive environment) to master greater challenges.

Faham Negini

Papers

Using affective state to adapt characters, NPCs, and the environment in a first-person shooter game