Arousal Level Determination in Video Game Playing Using Galvanic Skin Response A dissertation submitted in partial fulfillment of the requirement for the award of the degree of Master of Engineering in Electronic Instrumentation and Control Submitted By: Navjot Singh Roll No.: 801151014 Under the Guidance of: Dr. Ravinder Agarwal Professor Department of Electrical and Instrumentation Engineering Department of Electrical and Instrumentation Engineering Thapar University, Patiala Patiala – 147004, Punjab, India July 2013 i | P a ge ii | P a ge Acknowledgement First of all, I thank God for providing me such an opportunity and support. The present work was carried out under the supervision of, Dr. Ravinder Agarwal, Professor, Electrical and Instrumentation Engineering Department, Thapar University, Patiala. His advice, support and kind encouragement on thesis and professional issues have effectively guided me to right path. I take this opportunity to convey my sincere thanks and deep sense of gratitude to him, for his invaluable guidance, suggestions, inspiration and constant encouragement throughout the period of this thesis work. My sincere thanks to Dr. Smarajit Ghosh, Head of Electrical and Instrumentation Engineering Department, for his kind support and directing me in field of research based on his extensive knowledge. Timely help and support by Mr Nirbhowjap Singh, Assistant Professor, Electrical and Instrumentation Engineering Department, is gratefully acknowledged. All staff members of Electrical and Instrumentation Engineering Department for providing me hardware‘s as needed for completion of thesis. I want to express my appreciation to each and every person who directly or indirectly helped me to complete my thesis. Finally, I would like to express my gratitude to my family for their moral support, encouragement and blessings without which this work would not have been completed. Navjot Singh iii | P a ge Abstract Potentials for making computer games more engaging are put forward with reliable improvements in technologies for emotional recognition of human beings. Galvanic skin response is a nonintrusive easily captured physiological signal which is an indicator of autonomic nerve response as a parameter of the sweat gland function. It is oftenly used to evaluate the affective state of user’s stress and arousal level. In this paper galvanic skin response was studied for two different tasks of playing a videogame namely, playing games of his own choice and other not of his choice with varied difficulty levels. Frequencies produced corresponding to galvanic skin response variation, against variations in difficulty levels encountered during video game playing found varying in a wide range of 29 Hz to 120 Hz depending on the expertise and comfort level of player. We used GSR measurement module by Biokit India and the frequency was observed using digital oscilloscope, Tektronix MSO 2014 which is enabled with the feature of saving signal in USB flash drive. PASW was used as statistical methods to analyse the signals which showed a 10 % rise in galvanic skin response as the difficulty level is increased in terms of obstacles and time. Important thing was observed that frequency of arousals increased with number of obstacles, while magnitude of arousals increased with type of difficulty involved in crossing obstacles. iv | P a ge Table of Contents Acknowledgement ...................................................................................................................... i Abstract ..................................................................................................................................... iv List of Figures .......................................................................................................................... vii List of tables ........................................................................................................................... viii Chapter 1 .................................................................................................................................... 1 Introduction ................................................................................................................................ 1 1.1 PC Games ......................................................................................................................... 1 1.2 Emotions........................................................................................................................... 2 1.3 Emotion Detection Using Physiological Signals ............................................................. 3 1.3.1 Skin Conductivity ..................................................................................................... 3 1.3.2 Electrocardiogram ..................................................................................................... 4 1.3.3 Electromyogram ........................................................................................................ 5 1.3.4 Respiration ................................................................................................................ 5 1.4 Emotions and Video Games ............................................................................................. 7 1.5 Organization of Thesis ..................................................................................................... 9 Chapter 2 .................................................................................................................................. 10 Literature Review..................................................................................................................... 10 Chapter 3 .................................................................................................................................. 16 Galvanic Skin Response .......................................................................................................... 16 3.1 History ............................................................................................................................ 16 3.2 The Skin: Structure and electrodermal function ............................................................ 16 3.3 Sweat Glands .................................................................................................................. 18 3.4 Galvanic Skin Response measurements ......................................................................... 20 3.5 Recording sites and electrodes for GSR measurements ................................................. 21 3.6 Applications of GSR ...................................................................................................... 24 Chapter 4 .................................................................................................................................. 26 Equipment and Methodology ................................................................................................... 26 4.1 Experimental Protocol .................................................................................................... 26 4.2 Game Choice .................................................................................................................. 27 v | P a ge 4.3 Electrodes ....................................................................................................................... 29 4.4 Equipment ...................................................................................................................... 30 4.5 PASW (formerly SPSS Statistics) .................................................................................. 32 4.6 Parameters Calculated .................................................................................................... 34 4.7 Precautions ..................................................................................................................... 37 Chapter 5 .................................................................................................................................. 38 Results and Discussion ........................................................................................................... 38 5.1 Individual Statistics ........................................................................................................ 38 5.2 Mode............................................................................................................................... 44 5.3 Mean ............................................................................................................................... 45 5.4 Standard Deviation ......................................................................................................... 46 5.5 Analysis .......................................................................................................................... 47 5.6 Conclusion ...................................................................................................................... 53 5.7 Future Scope ................................................................................................................... 54 References ................................................................................................................................ 55 vi | P a ge List of Figures Figure1: PC Game Components ................................................................................................ 1 Figure 2: Examples of Basic Emotions ...................................................................................... 2 Figure 3: Position and Representative Waveforms of the GSR Sensors ................................... 4 Figure 4: Position of Electrodes and Waveform of E.C.G Sensor ............................................. 4 Figure 5: Position and Waveform of EMG Sensor for Stress Measurement ............................. 5 Figure 6: Position and Typical Waveform of Respiration Sensor ............................................. 6 Figure 7: Various Sources of Physiological Signals .................................................................. 7 Figure 8: Various Audio-visual Channels to Capture Emotions ............................................... 8 Figure 9: Skin Structure ........................................................................................................... 17 Figure 10: Sweat Gland ........................................................................................................... 19 Figure 11: Shows the Various Suggested Locations for Electrode Placement ........................ 22 Figure 12: Simple Electrode for GSR Measurement ............................................................... 24 Figure 13: Signal Acquired ...................................................................................................... 26 Figure 14: Wild Wild Taxi Game ............................................................................................ 27 Figure 15: Hill Climb Race ...................................................................................................... 28 Figure 16: Screen Shot of Assassin Jane Doe .......................................................................... 28 Figure 17: Conductive Rubber Electrodes ............................................................................... 29 Figure 18: Block diagram of GSR measurement apparatus..................................................... 30 Figure 19: Block Diagram of Experimental Set Up................................................................. 31 Figure 20: R to F Converter ..................................................................................................... 31 Figure 21: Data View of PASW .............................................................................................. 32 Figure 22: Variable View of PASW ........................................................................................ 33 Figure 23: Output File of PASW ............................................................................................. 33 Figure 24: Chart of Observations of Subject 1 ........................................................................ 39 Figure 25: Chart of Response of Subject 2 .............................................................................. 40 Figure 26: Chart of Response of Subject 3 .............................................................................. 41 Figure 27: Response of Subject 4 ............................................................................................ 42 Figure 28: Chart Showing Response of Subject 5 ................................................................... 44 Figure 29: Plot of Mode of Experiment ................................................................................... 45 Figure 30: Chart of Mean of Experiment ................................................................................. 46 Figure 31: Plot of Standard Deviation of Experiment ............................................................. 47 vii | P a ge List of tables Table 1: Statistics of Subject 1................................................................................................. 38 Table 2: Statistics of Subject2.................................................................................................. 39 Table 3:Statistics of Subject 3.................................................................................................. 41 Table 4: Statistics of Subject 4................................................................................................. 42 Table 5:Statistics of Subject 5.................................................................................................. 43 Table 6 : Mode Table of Experiment ....................................................................................... 44 Table 7: Mean of Experiment .................................................................................................. 45 Table 8: Standard Deviation of Whole Experiment ................................................................. 46 Table 9 : Values of Own Game and Level 1 ............................................................................ 48 Table 10: T-test values of level 1 and own game .................................................................... 48 Table 11: Values of Own Game and Level 2 ........................................................................... 49 Table 12 : T-test Values for Own Game and Level 2 .............................................................. 49 Table 13: Values of Own Game and Level 3 ........................................................................... 50 Table 14: T-test Values of Own Game and Level 3 ................................................................ 50 Table 15: Values of Level 1 and Level 2 ................................................................................. 51 Table 16: T-test Values of Level 1and Level 2 ........................................................................ 51 Table 17:Values of Level 1 and Level 3 .................................................................................. 52 Table 18: T-test values of Level 1 and Level 3 ....................................................................... 52 Table 19: Values of Level 2 and Level 3 ................................................................................. 53 Table 20: T-test value of Level 2 and Level 3 ......................................................................... 53 viii | P a ge Chapter 1 Introduction This Chapter introduces basics of emotion sensing in computer gaming using physiological changes detected using various bio-medical sensors. With the growing competition in the market, for a videogame to be popular it should attract as many players as possible. The main aim of the video game developers should be designing games in a way such that it provides players with real time like changes and adapt according to the emotions of the player. Designing should be such a way that it provides the same user experience to all the audience irrespective of player expertise and motivation. 1.1 PC Games A video game is an electronic game that involves human communication with a user interface to generate visual feedback on a video device. PC games traditionally known as computer games are video games played on a general purpose computer rather than a dedicated video game console or arcade machine. They are characterized by the lack of any centralized controlling authority and greater capacity in input processing and output. The input device used to manipulate PC games according to user are known as game controller they vary from system to system mainly they include keyboard, mouse, joysticks etc., As shown in Figure 1. Game designers are focusing on adaptable games to make them interesting throughout their usage. Usually they realize the concept of adaptability by linearly increasing the level of difficulty when one proceeds from lower levels to higher levels which ignores the expertise level of player and mood of player while playing, by which game loses its appeal after a certain period and become obsolete [1]. Figure 1: PC Game Components 1 | P a ge State-of-the-art methodology to make PC games adaptable is to include the emotions of the player and changing the game play according to it rather than predetermined way. Previous researches in videogames indicated that emotionally adaptive games augment the players gaming experience by adapting their mechanisms to the emotional state of the player [2].This shows that for a videogames to achieve some extent of success in today’s market it should be emotionally adaptive by which it can appeal to maximum number of players. Preferably videogames should be adept of dynamically changing their design in light of the player’s ongoing interactions with the videogame. So making the gaming know-how fit the individual user. However creating adaptive gameplay is not something to be taken lightly. It is required to consider the motivation of the users: why they want to play, their experience and skills: how able are they to play, and detection: how to identify when change is necessary [1]. 1.2 Emotions Emotion is an individual, sensible experience that is portrayed primarily by psychophysiological expressions, biological reactions and mental states [3]. Emotion is often associated and considered jointly influential with mood, temperament, personality, disposition and motivation. The composition of emotion is closely interconnected to arousal of the nervous system with various situations and strengths of arousal relating, deceptively, to particular emotions. Although those acting largely on emotion may seem as if they are not thinking, thought is an important aspect of emotion, particularly the interpretation of events. Basic emotions are anger, fear, arousal, sorrow, happy etc. Figure 2 shows some examples of emotions. Figure 2: Examples of Basic Emotions 2 | P a ge