Galvanic Skin Response Pseudoscience
by Steven Novella via Science-Based Medicine
Selling snake oil is all about marketing, which means that a good snake oil product needs to have a great angle or a hook. Popular snake oil hooks include being “natural,” the product of ancient wisdom, or “holistic.”
Perhaps my favorite snake oil marketing ploy, however, is claiming the product represents the latest cutting-edge technology. This invariably leads to humorous sciencey technobabble.
There are also recurrent themes to this technobabble, which often involve “energy,” vibrations and frequencies, or scientific concepts poorly understood by the public, such as magnetism and (of course) quantum effects. Historically, even radioactivity was marketed as a cure-all
One category of technical pseudoscientific snake oil measures some physiological property of the body and then claims that this measurement can be used for diagnosis and determining optimal treatment. For example, machines might measure brain waves, heart rate variability, thermal energy or (the subject of today’s article) the galvanic skin response.
These are all noisy systems – they are highly variable and produce a lot of random results that can be used to give the impression that something meaningful is being measured. Systems that rely on these measurements to make highly specific determinations are no different than phrenology
or reading tea leaves, but they look scientific.
The galvanic skin response
I was recently asked to look into a product called Zyto technology. This is an electronic device that you place your palm on top of so that it can read your “galvanic skin response” (GSR) to specific stimuli. It then uses your responses to prescribe a specific treatment.
The GSR is actually an older term for what is now called electrodermal activity
(EDA), which is simply the electrical conductance of your skin (Harriet Hall has written about such devices before
). Skin conductance is primarily affected by sweat, as salty water is an excellent conductor. So essentially the machine is measuring how sweaty your palms are.
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