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What are heart rate and galvanic skin response and how do they work?

As summarised by acclaimed Portuguese neuroscientist Antonio Damasio, human beings are not “thinking machines that feel, rather we are feeling machines that think”: it is in fact the oldest, most instinctive and unconscious part of our brain, the so-called proto-reptilian and limbic systems, that primarily determines our reactions, behaviours and decisions in response to any stimulus.

This is why, in order to fully understand how people think and choose, even when shopping, it is crucial to investigate which mechanisms and unconscious reactions to a stimulus intervene in the decision-making process: measurements that are impossible to intercept with traditional market research, but only by exploiting the potential of neuromarketing and its tools, such as heart rate and galvanic skin response.

biofeedback heart rate galvanic skin response

What does the term biofeedback mean?

Generally referred to collectively as “biofeedback”, heart rate and galvanic skin response track and measure physiological and instinctive responses, the body’s biological feedback in reaction to a stimulus.

To do this, neuromarketing uses specific instruments that are useful particularly in the medical field, such as the electrocardiogram (ECG). The ECG records changes in heartbeat and the electrical activity linked to heart contractions, which are important indices in a neuroscientific test to study the degree of emotional and unconscious activation of an individual. The indices transmitted by the ECG include the Heart Rate (HR), which is the rate at which the heart contracts and is measured in bpm (beats per minute).

biofeedback heart rate galvanic skin response

How does the heart rate work?

Heart Rate indicates the number of times the heart contracts during a minute and, on the basis of this parameter, observes and measures changes in the individual’s physiological state: the heart rate is regulated by our autonomic nervous system, which is also responsible for processing emotions.

Positive emotions are usually responsible for an increase in heart rate, while negative or relaxing emotions lower it. Besides being highly indicative of an individual’s emotional activation in response to an input, the Heart Rate has another practical advantage: two electrodes placed on the chest or both wrists are all it takes to track the heartbeat, and there are even less invasive alternatives, such as infrared optical sensors.

What is the galvanic skin response and how does it work?

Another index included in the definition of biofeedback, the Galvanic Skin Response, often referred to as GSR for short, allows us to observe and measure electrical changes based on perspiration. This parameter is known as skin conductance, and it too is essential for observing our body’s emotional activation response to a stimulus. Intense perspiration is usually associated with strong emotions, stress and agitation.

Aside from more obvious reactions, our skin is always subject to small variations in perspiration: when a stimulus arouses our emotions, the skin’s conductance changes, indicating our interest in that stimulus. A completely automatic response, which we are often completely unaware of at rational level: perspiration too is regulated by the autonomic nervous system.
Again, the tool used to measure skin conductance is easy to carry and manage. It consists of two electrodes placed in contact with the skin, usually on the fingers or wrist, to measure skin conductance.

biofeedback heart rate galvanic skin response

Heart rate and GSR: when are they used by neuromarketing?

Although it is rare for a neuroscientific test to use biofeedback tools alone, they are rarely excluded from a neuroscientific analysis, precisely because, together with the instrumentation that directly investigates brain function (such as functional magnetic resonance imaging), they provide a complete picture of a person’s unconscious reactions.

Thanks to these parameters, neuromarketing is a useful additional solution in support of traditional analysis methods, which only investigate rational and conscious aspects, informing and demonstrating whether a given communication input, be it a TV commercial, social media campaign or product packaging, is really able to engage people, capturing their attention and motivating their purchasing choices.