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Psychophysiology(biometrics) and games
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Psychophysiology(biometrics) and games



A lecture on Psychophysiological (Biometric) methods given to Hanze University students in 2011. If you want to see more on this topic please check out these slide shows: ...

A lecture on Psychophysiological (Biometric) methods given to Hanze University students in 2011. If you want to see more on this topic please check out these slide shows: http://www.slideshare.net/acagamic/next-generation-testing-biometric-analysis-of-player-experience and http://www.slideshare.net/keylimeinteractive/exploring-eye-tracking-for-games-user-research-a-case-study-of-lessons-learned



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Psychophysiology(biometrics) and games Psychophysiology(biometrics) and games Presentation Transcript

  • Psychophysiology & Games Ben Lewis-Evans
  • >Introduction  Kia Ora  What and why?  Biology  Emotion & Feelings  The Measures  Use in Games  Limitations  Demonstration
  • http://www.gamasutra.com/view/feature/6341/game_testing_and_research_the_.php
  • >What is Psychophysiology?  Examining the signals the body provides in an attempt to gain insight into what psychological processes are occurring  aka Whatcya Thinking? - Emotion - Mental Workload - Stress/Tension
  • >Why use it?  Questionnaires, focus groups, interviews, talk out loud, heuristic analysis, psychometric categories (“player types”) - All Qualitative, All Subjective  Gameplay data & Behavioural Observation - Objective, but lacking in the why
  • >Physiological Methods  Pros: - Objective, covert(ish), continuous, quantifiable, reliable(ish), replicable(ish), with good empirical power(sometimes) and can be collected automatically  Cons: - Expensive, intrusive, difficult to analyse, and time consuming (setup and analysis)http://www.slideshare.net/acagamic/next-generation-testing-biometric-analysis-of-player-experience
  • >Biology  Psychology = Mind?  Embodied Cognition - Psychology = Body  Communication, control, monitoring and maintenance: - The Nervous System
  • >The Central Nervous System  CNS for short  Skull and top of the Spine - Hidden away - Hard to access (for non-ninjas)  Measures: - fMRI - PET scans - EEG
  • >Peripheral nervous system (PNS)  Controls internal organs (involuntary muscles) and voluntary muscles  Two parts - Parasympathetic - Rest, sleep - Maintaining body state - Sympathetic - Action, excitement - Emergency reactions  Easier to access (no ninjas required)  Measures: - EMG, EDA, Cardiovascular
  • Berntson et al., 1994
  • >Emotion and Feelings  Arousal and Valence High Activation Scared - x x – Excited Unpleasant Pleasant Bored - x x – Relaxed Low Activation
  • >Emotions vs Feelings  Somatic Marker Hypothesis (Damasio, 1994) - Emotions - Body states (PNS and CNS) - Can be unnoticed and unconscious - Feelings - Subjective (conscious) impressions of Emotions
  • Psychophysiological Measures
  • >Electroencephalography (EEG)
  • >EEG  Brain activity (CNS)  Collects frequency information: - Alpha 8-14 Hz (calm, mental work) - Beta 14-30 Hz (focused, engaged mental work) - Delta 1-4 Hz (trance, sleep, fatigue) - Theta 4-8 Hz (emotions, sensations) - Gamma 30-50 Hz (Information processing – not often measured)
  • >EEG Game Research  Nacke 2010 – Wiimote vs Controller – General increase in brain activity (EEG) when using the Wiimote – In the delta band & mainly for hardcore players (Delta is relaxation/sleep/fatigue)
  • >EEG  Advantages - Access to the CNS  Disadvantages - Expensive - Time consuming - Invasive - Artefacts - Hard to interpret
  • >Electromyography (EMG)
  • >EMG  Measures movement/activation in muscles through the use of electrodes (PNS)  Primarily interested in facial muscles for Emotion (Valence) – other muscles for tension?
  • >Facial EMG  Three muscles of interest: - Corrugator supercilii (brow) – negative emotion - Zygomaticus major (cheeks) – positive emotion - Orbicularis oculi (eyes)– expression of enjoyment and “genuine pleasure”
  • >EMG Game Research  Nacke & Lindley 2008 – Flow and Immersion in a FPS - Effects of “boring” vs “flowing” gameplay in Half- Life 2 on EMG. - More positive affect (Valence) on the flow levels.
  • >Facial EMG  Advantages - More sensitive than image processing - Valence  Disadvantages - Intrusive - Unnatural reactions (monitoring effect) - Expensive - Artefacts - e.g. No talking
  • >Electrodermal activity (EDA or GSR or SC or SCR)
  • >EDA  Changes in Skin Conductance (PNS) As long as 1-5 seconds - Sweat gland activation  Emotion (Arousal)  Workload  Tonic & Phasic - Average vs Event
  • >EDA Game Research  Nacke & Lindley 2008 – Flow and Immersion in a FPS - Effects of “boring” vs “flowing” gameplay in Half- Life 2 on EDA. - More arousal effect on the flow levels.
  • >EDA Game Research  Dying is fun?  Ravaja et al (2008) - EDA increased for - Opponent Killed - Player Killed - EMG (Zygomatic and Orbicularis) - Increased for longer when player killed
  • >EDA  Advantages - Easier to collect - Just 2 electrodes - Non-intrusive - Inexpensive  Disadvantages - Noisy signal - Large individual differences - Slow decay and response lag - Specificity and artefacts
  • >Cardiovascular (HR, HRV, IBI, BP)
  • >Cardiovascular  Measurement of heart activity (PNS) - Heart Rate (HR) - Heart Rate Variability (HRV) - Inter Beat Interval (IBI) - Blood Pressure (BP)  Rhythms  Useful as workload and Emotion (Arousal) measures
  • >HR, IBI, HRV, BP  HR - Number of beats per unit of time - with Effort/Arousal (initial)  Inter Beat Interval - Time between beats - with Effort/Arousal (initial)  HRV - Variability in the IBI - with Effort/Arousal (initial)  BP - Pressure of the blood - with Effort/Arousal (initial)
  • >IBI/HR changes visible with the naked eye REST TASK
  • >HR, IBI, HRV, BP  Changes over time (~20 minutes) move away from reactive “fight or flight” and towards protective homeostasis - Meaning that HR decreases and HRV increases  HR(IBI) vs HRV - HR more sensitive to Emotion (Arousal) - HRV more sensitive to Mental Workload - 10 hz frequency band - Use both
  • >HR
  • >HRV
  • http://gamasutra.com/blogs/BenLewisEvans/20110124/6676/My_Heart_on_Halo.php
  • >Cardiovascular Game Research  Ravaja et al 2006 – Increase in self-reported arousal, cardiac interbeat activity, and zygomatic and orbicularis oculi EMG when moving from playing vs computer to vs a co- located stranger to vs a co-located friend
  • >Cardiovascular (HR, HRV, BP)  Advantages - Cheap and easy measurement (HR) - Captures emotion (arousal) and Workload (HRV)  Disadvantages - Intrusive (BP, HRV) - Specificity problems (affected by many things) - Complex analysis (HRV)
  • >Respiration
  • >Respiration  Part of the Cardiovascular system (PNS)  Sensitive to workload/effort  Rhythms again  Respiration impacts on other cardiovascular measures and on EDA
  • >Respiration  Advantages - Relatively cheap and easy to measure  Disadvantages - Not as sensitive as some other measures - Artefacts (No Talking)Often overlooked, but in general it should alwaysbe measured if you are measuring otherCardiovascular variables or EDA
  • >Eye tracking
  • >Eye Tracking  Measurement of Eye Movement - Can be done with EMG - Electrooculogram (EOG) - More commonly via an infrared light camera system - Measures - Where you are looking and for how long
  • Heat Map
  • Fixations
  • >Eye Tracking  Advantages - Captures gaze and duration - Relatively non-invasive - Good for User Interface  Disadvantages - Gaze does not equal attention - Moving scenes with Depth - Calibration! - Glasses
  • Biometric Games
  • “[adding biometric readings forplayers to see while playing was]the most enjoyable thing we havedone" - Valve
  • Summary
  • >Limitations - Psychophysiology  Fairclough (2009): - Inference - One-to-Many - Many-to-One - Specificity and generality - Different tasks, people and situations - Validity - Objective, yes, but to what?
  • >Some comment from the industry“We don’t use it...because the costs (both in equipment and time) hasalways seemed to outweigh the benefits. Often we are better serveddoing "standard" usability/playtests as we can do them quicker, faster,and cheaper. ”“Overall, I would say we find using biometrics to be incredibly useful,but it depends on the genre of the game and what our clients areinterested in knowing. ”“…we also dont use many of the biometrics due to the potentiallyinvasive nature of some of the measuring instruments. We strive toprovide a neutral, low stress environment for our tests”“…we can imagine the benefits of using biometrics an such in somecases, the imperatives of production usually mean that we wouldnthave time to use them in an efficient manner”
  • >So?  Not a silver bullet  Do not use in isolation - Combine with other measures (not talking)  Try to look at Tonic and Phasic reactions  Use Baselines!  Beware of artefacts!! (not the BoP kind..)
  • >So?  Great at arousal/workload and therefore engagement. - Not so good at valence (Pleasant vs Unpleasant)  Better at detecting things (emotions?) that players may not be aware of themselves - If players are not aware of it though, does it actually affect their enjoyment/behaviour? - Will it influence their purchasing?
  • >Want more?  Check out these presentations: - Nacke, Next Generation Testing – Biometric Analysis of Player Experience: http://www.slideshare.net/acagamic/next- generation-testing-biometric-analysis-of- player-experience - Rodriquez & Steiner, Exploring Eye Tracking for Games User Research: http://www.slideshare.net/keylimeinteracti ve/exploring-eye-tracking-for-games-user- research-a-case-study-of-lessons-learned
  • All images used in thispresentation belong to their respective copyright holders.If an image belongs to you and you wish it removed please notify me at b.lewis.evans@rug.nl