Learn how to interpret the galvanic skin response measures provided by Tobii Pro Lab.
GSR can add valuable insights to your eye tracking experiment about the emotional arousal state of a participant during various situations. Pro Lab offers a set of GSR metrics that are frequently used to quantify skin conductance responses (SCRs) and arousal levels during an experiment. The type of research question and experimental design will determine which GSR metrics are more appropriate to answer your research question.
Pro Lab provides two SCR-related metrics: ER-SCR amplitude and SCR count. An SCR is a temporary increase of the GSR signal amplitude that gives information about what specific moments caused an emotional response within the participant. When an SCR happens between 1 and 5 seconds after an event, the SCR is then classified as an event-related SCR (ER-SCR) and the amplitude of the SCR gives an indication of the intensity of the emotional response towards the event. Examples of where SCR-related metrics are useful to get insights about the emotional reactions are:
Pro Lab also provides a metric related to the general emotional arousal state of a participant: GSR average. When environmental conditions are kept constant, the slow fluctuations in the GSR signal (tens of seconds to minutes) reflect changes in the emotional arousal level of a participant. The researcher can use the GSR average metric to determine if a participant is getting stressed, frustrated or relaxed during the course of the test session. Examples of where the GSR average metric is useful to get insights about general emotional arousal levels are:
Besides the three metrics described thus far, the Data Export function of Pro Lab offers access to raw or filtered GSR data as well as information about the onset and peak time of all the SCRs in the data. The researcher can use this information to calculate additional metrics based on individual needs. Examples of additional metrics include, a list of all SCRs and their main parameters, and data standardization calculations or ratio of non-specific SCR per participant (NS-SCR).
Finally, due to the GSR signal characteristics, there are a few points that a researcher must consider to ensure the GSR results are statistically valid to answer their research question. These include: