Physiological Response Measurements
Galvanic Skin Response. Galvanic skin response (GSR), also referred to as skin conductance response (SCR) or electrodermal activity (EDA), is the property that momentarily makes our skin a better conductor of electricity when we are physiologically aroused. ZIYUN Grove GSR Sensor,Galvanic Skin Response Sensor,Detects conductance of Skin,Finger Straps for electrodes,Used for Detecting Strong Emotions,Skin Current Sensor,Sleep Quality Monitor. Get it as soon as Tue, Jun 11. FREE Shipping on orders over $25 shipped by Amazon.
Jennifer Romano Bergstrom, ... Mike McGill, in Eye Tracking in User Experience Design, 2014
Skin Conductance
Skin conductance, (a.k.a. EDA or galvanic skin response, GSR) is frequently used as a psychophysiological method, because it is easy to use and largely non-intrusive for the participant. EDA and GSR largely assess activity of the “fight-or-flight response,” which is controlled by the sympathetic nervous system. The fight-or-flight response is activated in response to emotionally charged stimuli. The extent to which this response is activated can be measured by the secretion of sweat; more sweat is released during a strong emotional response compared to a weak one. The hands have a high density of sweat glands that are sensitive to changes to external stimuli (e.g., temperature) as well as internal stimuli (e.g., emotions changes). EDA data can be collected from the finger (Figure 4.13), wrist, or palm.
EDA is associated with stress, excitement, engagement, frustration, and anger and correlates with self-report measures of arousal (Lang et al., 1993). Attention-grabbing stimuli and attention-demanding tasks increase the frequency and magnitude of GSRs.
EDA is often used in decision making and emotion research. A recent study assessed EDA during interactions with an online poker game, where numerous and fast decisions were necessary (Palomäki et al., 2013). Poker hand strength was associated with EDA response, and thus, EDA was useful in indicating the anticipated utility of poker game decisions.
Figure 4.14 displays EDA data from a participant who interacted with a tablet application. When she experienced difficulties using the app, her arousal increased. Her verbalizations of frustration (first, that the keyboard covered part of the screen and then later, when she got an error message) were consistent with the points of EDA arousal. EDA allowed us to learn the precise points of frustration and in an objective manner. In this case, the arousal was consistent with the verbalizations, but in other cases, such as when participants do not verbalize frustrations, EDA can be extremely useful in understanding the user experience.
How Does Skin Conductance Measure Emotion?
EDA is composed of tonic and phasic activity. Tonic changes in arousal occur slowly and are measured over a long period of time. Tonic level of emotional arousal can be measured, for example, at the onset and offset of an advertisement and are in essence a “baseline” level of arousal. Phasic activity, however, is composed of rapid secretions of sweat in response to a discrete stimulus. While change in tonic levels of arousal are measured over time, phasic activity occurs quickly in response to stimuli that are startling, surprising, funny, or disgusting.
Researchers are interested in measuring both the tonic and phasic activity in their participants, but accurate measurement can be problematic. While EDA data are useful, dynamic analysis of tonic and phasic activity is complex and requires trained experts (Lajante et al., 2012).
A general problem in consumer neuroscience is that clearly specified threshold values are often left out of reports. Researchers often ignore the fact that activity overlaps, but it is inevitable because the rise time of a skin conductance response (SCR) is shorter than the recovery time, and this information may be important when analyzing results.
When researchers are interested in how emotional arousal changes over time, they often use methods that compare only the tonic levels of skin conductance (SC). These methods are questionable because they ignore the phasic activity and only tell half the story. In other situations, when researchers want to measure phasic activity, they may use a method that compares just the mean change score before and during stimulus onset. Unfortunately this method is considered arbitrary and not entirely correct.
Using the sum of amplitudes of the SCR is the most common method in consumer neuroscience, but it too is still not entirely accurate. For the analysis of SCR data to be fully correct, it needs to incorporate information about the amplitude and duration of an SCR. One such correct method (discussed in Lajante et al., 2012), calculates the integrated SCR (ISCR). Calculating the ISCR will more accurately describe an SCR in your users and will help you to make comparisons between user groups. Many UX researchers will sacrifice best practices and proper analytic techniques in favor of easier, yet incorrect analyses. This is bad practice and should be avoided.
Those more interested in how to properly assess and interpret EDA data are encouraged to examine the research of Lajante et al. (2012).
As with other physiological response measures, EDA (GSR) show the intensity of arousal, but not the valence. Therefore it is important to couple SCR measurements with other explicit measures so we can know if users have a positive or negative experience. Similar to the facial emotion recognition, EDA has strong potential for measuring the user experience, but more research is certainly needed. UX researchers should continue to use the method and share their work so we can continue to learn from each other and move the technique forward in the field.
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galvanic skin response
n. Evidence of emotional arousal obtained by attaching electrodes to any part of the skin and recording momentary changes in perspiration and other functions of the autonomic nervous system.
galvanic skin response
n (Psychology) a change in the electrical resistance of the skin occurring in moments of strong emotion; measurements of this change are used in lie detector tests. Abbreviation: GSR
Noun | 1. | galvanic skin response - a change in the electrical properties of the skin in response to stress or anxiety; can be measured either by recording the electrical resistance of the skin or by recording weak currents generated by the body electrical skin response, electrodermal response, Fere phenomenon, GSR, psychogalvanic response, Tarchanoff phenomenon response, reaction - a bodily process occurring due to the effect of some antecedent stimulus or agent; 'a bad reaction to the medicine'; 'his responses have slowed with age' lie detector - a polygraph that records bodily changes sometimes associated with lying |
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