Category Archives: Brittany’s Blog

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Dynamic Difficulty Adjustment in Computer Games Through Real-Time Anxiety-Based Affective Feedback

Dynamic Difficulty Adjustment in Computer Games Through Real-Time Anxiety-Based Affective Feedback



Liu, C., Agrawal, P., Sarkar, N., & Chen, S. (2009). Dynamic difficulty adjustment in computer games through real-time anxiety-based affective feedback. Intl. Journal of Human–Computer Interaction25(6), 506-529. DOI: 10.1080/10447310902963944


In this paper, a dynamic difficulty adjustment (DDA) mechanism is used to adapt the difficulty of a game to a player’s affective state (anxiety), in real-time. The physiological signals used as indicators of anxiety were measurements of cardiovascular, electrodermal and EMG activity.  In addition, multiple features were derived from this set of signals.  A two-phase experiment was conducted to first formulate a player’s affective model and then use the model to apply an affective-based DDA mechanism to a game.  In the first phase, two computer games were created (Pong and anagram game), intentionally designed to provoke different levels of anxiety by varying important game parameters.  When playing each game, the participant was stopped at equally spaced time intervals to report their anxiety level. A training dataset was generated for each participant, comprised of normalized perceived anxiety levels and measures of the physiological features.  The dataset was Continue reading

Effective Affective User Interface Design in Games

Effective Affective


Johnson, D., & Wiles, J. (2003). Effective affective user interface design in games. Ergonomics46(13-14), 1332-1345. DOI: 10.1080/00140130310001610865


The authors propose ideas for integrating methods of game design into the affective design of non-leisure software applications.  The first author used Nielsen’s usability heuristics as guidelines for assessing a set of games to identify where and how the heuristics were violated, focusing on contraventions which impact flow.  The results expose contraventions which either facilitate or inhibit flow.  In terms of facilitating flow, games present minimal information to increase immersion, exhibit inconsistency in controls to lower cognition and encourage the occurrence of errors, to increase satisfaction during success.  In terms of inhibiting flow, errors are encountered when navigating game menus, the player is sometimes forced to wait leading to low flexibility and loss of control, there is often lack of online help and there exists cross-platform differences among games.

Next, a follow-up study was conducted to investigate the cross-platform differences among games.  The study involved comparing user interface design and user affective experience.  The games used were “Tony Hawk pro skater 2” (THPS2) and “Quake 3 Arena” (Q3A), both in the PC and console versions.  The user interface comparison revealed differences in the menu design of Q3A, where the console version had a menu that was confusing to navigate.  Cross-platform case studies consisting of interviews were performed to examine user’s affective experience when playing the two games, focusing on the differences between consoles.  All participants preferred playing Q3A on the PC, compared to its console version.  There were mixed opinions regarding playing preferences of THPS2. 

The authors identified contraventions of well-known usability guidelines, which impact positive affect in games.  They briefly investigated cross-platform differences in games, specifically related to affective experience and interface design.  The presented information may be useful to assist the affective design of non-leisure software applications.  Future work involves Continue reading

Usability recommendations in the design of mixed interactive systems – Bonus Blog


Charfi, S., Dubois, E., & Scapin, D. L. (2009, July). Usability recommendations in the design of mixed interactive systems. In Proceedings of the 1st ACM SIGCHI symposium on Engineering interactive computing systems (pp. 231-236). ACM. Doi: 10.1145/1570433.1570475.


Mixed Interactive Systems (MIS) consist of multiple interaction methods and technologies.   Shifting the focus of interaction design for MIS from technological device capabilities, to a user-centered approach will help address usability concerns these complex systems introduce.  A survey of existing MIS-relevant user studies was performed to comprise a list of topics describing typical characteristics of MIS’.  Next, design and usability recommendations from Tangible User Interface, Augmented Reality and Virtual Environment system development were summarized.  Then, the usability recommendations for MIS were extracted from the surveyed evaluations and described by recommendation characteristics.  The recommendations were classified based on the target focus of the recommendation.  Lastly, the seven categories of recommendations were used to structure a preliminary interaction model for a group creation task, supported by a museum application.


In creating the interaction model, the authors of the paper based their design decisions on existing recommendations published in literature.  Although this Continue reading

Biofeedback Game Design: Using Direct and Indirect Physiological Control to Enhance Game Interaction



Nacke, L. E., Kalyn, M., Lough, C., & Mandryk, R. L. (2011, May). Biofeedback game design: using direct and indirect physiological control to enhance game interaction. In Proceedings of the 2011 annual conference on Human factors in computing systems (pp. 103-112). ACM. Doi:10.1145/1978942.1978958


This paper focuses on augmenting existing game controls by incorporating physiological input from the player.  The direct physiological controls used were: leg muscle flexing, breathing rate, breath temperature sensor and eye gaze, and the indirect controls were: heart rate and galvanic skin response.  These physiological inputs were used to trigger and manipulate gameplay actions or effects.  A user evaluation was conducted to explore how players assess game controllers enhanced with physiological input.  For the evaluation, a Continue reading