I showed him the announcement of the Tesla Model 3 because he was curious. And I just see a tiny arousal in the data. Then I showed him videos of the 1g acceleration of the model S. Same here, he had less arousal than I thought.
Yesterday I recorded his GSR with comedy videos and he laughed. Still, his variance was similar to the image case. I think I placed correctly the electrodes on his fingers, also because I made different attempts.
So far I never saw something like this, I know that some people have less variance than others, but I am worried by the values of my dad.
This is one case where there are high and low variance subjects: http://www.shimmersensing.com/assets/images/content/case-study-files/Emotional_Response_27July2015.pdf
I also have a reading of my mother, but she was tired so the low variance in her case could be justified.
There is quite a few things that can produce results like this. Unfortunately it is not always easy to identify which is the causal factor.
Firstly there is individual differences: Some people just are non-responders,
Secondly: If the starting level (tonic) is quite high then the response level (phasic) will look very low because of a ceiling effect,
Thirdly: The equipment and software could have the wrong filters causing the responses to not be seen correctly,
Forthly: The skin preparation and cleaning procedure you are using could be creating noise/bad connections.
I find the biggest responses come from a surprise/jump try that to see if you can get a response.
Good Luck
I agree with Marc! I worked in a lab for 2 years as a research technician, mostly running psychophysiology studies.
Definitely check your filters. We typically would just have participants wash their hands with water, since soap or alcohol can cause the skin to dry up, resulting in lower GSR. You can also try using isotonic gel on the sensors to get better conductance. If you are seeing normal skin conductance responses in others with the same filter settings and procedures, it's likely that he is just a non-responder which seems to be the case for about 10% of individuals, according to the literature.
Hope this helps, good luck!
I use no filters, just raw data. Consider I'm using a groove GSR sensor.
I'm not sure I understood "Secondly: If the starting level (tonic) is quite high then the response level (phasic) will look very low because of a ceiling effect".
"We typically would just have participants wash their hands with water, since soap or alcohol can cause the skin to dry up, resulting in lower GSR." I don't know if my parents washed their hands, we use the same products so I could expect the same effect even with me, and this didn't happen.
I think the only explanation I like the non-responder hypothesis, I never found the 10% amount. Do you have some sources where I can check the median and average age of the subjects that were labeled like that?
To answer the second point: The typical skin conductance level is between 0-30 uS (microsiemens) with a response being anywhere from 0.5-10 uS (depending on person and stimulus). If your parents starting level was 30uS then a response might be masked by the starting level as in it can't go any higher.
Scerbo et al. (1992) and Boucsein et al. (2012) are two papers that will get you started on some of the finer points of the GSR. Most psychophysiology textbooks have decent introductions as well.
Gabriele,
The chapter on the Electrodermal System in the Handbook of Psychophysiology (3rd edition) by Cacioppo, Tassinary, & Berntson cites that about 10% of the typically developing population are GSR nonresponders (p. 173). They reference review articles by Bernstein et al. (1982), Dawson & Nuechterlein (1984), Ohman (1981), and Iacono, Sicken, and Beiser (1993) for this information.
Hope this is helpful!
If the electrodes are placed in the fingers and there is not much response, you could also try adhesive electrodes placed on the thenar and hypothenar eminences ( the left and right lower part of your palm). Another explanation for no sign of arousal is that basically your dad is not interested in cars. Also about shimmer GSR, at least 3 years ago, Shimmer 2R used to have 4 different resistors that you could choose from their software. Only one corresponds to each individual. So before you show someone a certain stimuli to measure arousal you need to check which one of the Shimmer resistor corresponds to their skin type (a word that scientists love; calibration). Perhaps that link might help; http://ftmedia.eu/819-2/
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