The galvanic skin response (GSR) is the most effective and sensitive physiological parameter that responds to changes in human sympathetic excitability and is a common indicator of emotional response. The galvanic skin response is also known as electrodermal activity (EDA), or galvanic skin conductance (SC).
GSR arises from the voluntary activation of the sweat glands of the skin, while the so-called sweating of the hands and feet is caused by emotional stimuli: whenever we experience a change in mood, GSR data show a distinct pattern that can be statistically quantified by observation.
The electrical skin response was first observed in 1888, when the French neurologist Fere reported that different physical and emotional stimuli – visual, auditory, gustatory, olfactory, etc. – could cause different changes in skin resistance. Fere concluded that the correlation with sensory and emotional stimuli suggests that the electrical skin response is an indicator of neural excitation.
Using GSR, it is possible to test the true mental state in the state of unconscious behavior, i.e., without doing subjective control of the cognitive state. Since skin electrical conductivity is regulated by autonomic sympathetic activity alone drives physical, cognitive and emotional states as well as fully subconscious levels of cognition.
Therefore, one cannot consciously control skin conductivity. It is this situation that makes GSR the perfect marker of emotional arousal, which provides a true insight into the processes that can be influenced by events on a person’s psyche and physiology.
Now, based on the understanding of GSR, researchers at NYU Tandon School of Engineering are developing wearable devices that can monitor mental states by measuring skin electricity in real time, which will also be a key milestone in wearable technology.
As mentioned earlier, skin electricity is associated with emotion-related activity in the brain, and thanks to simpler and faster algorithms, the new technology can accurately decipher a subject’s brain signals in a matter of seconds. In contrast, the traditional method of measuring neurological responses through the skin takes several minutes and does not allow for immediate wearable aspects.
Thus, the device offers new opportunities for monitoring and improving mental health and cognitive engagement. It is important to know that there are no reliable biomarkers in the medical field that can be used to diagnose psychological disorders. Psychiatrists’ attempts to find shortcuts to discover negative thoughts have always been fruitless, which has stalled many psychiatric developments.
It not only makes the diagnosis of mental illness slow, difficult and subjective, it also prevents researchers from understanding the true nature and causes of various mental illnesses, and from researching better treatments.
The method has been tested on 26 healthy subjects, and the team is currently working on how to integrate the algorithm model into wearable devices, including eliminating the “noise” of information caused by factors such as intense exercise, as well as finding potential partners to design and build devices that carry the algorithm. In the future, wearable devices will increasingly take over the monitoring of our health, both physical and psychological.