Biometrics and Experimental Consumer Psychology

Ben Ambridge

Galvanic Skin Response (GSR) (also known as Skin Conductance or Electrodermal Activity) is a measure of intensity of emotional arousal: when you’re worked up, you perspire, increasing the conductivity of your skin, which is then picked by the GSR monitor.

GSR can detect responses you aren’t even aware of

An important advantage of GSR over simply asking people how they feel is that it can detect emotional responses that customers may themselves be unaware of, or even trying to hide.

For example, how many customers do you think are aware that the colour of the background on an auction site can affect how they bid (or would admit it if they did)?

Not many, right? Well, a 2013 GSR study by Rajesh Bagchi1 at Virginia Tech found that a red background leads to emotional arousal, and hence to more aggressive bidding, than a blue background.

Beware, though, if customers are negotiating with a seller – rather than competing with each other – this aggression leads to lower, rather than higher, offers.

Arousal is not just romantic or sexual

When people learn that GSR measures arousal, they immediately think of romantic or sexual arousal, which typically peaks right at the start of a new relationship, before plateauing off as the relationship becomes more established.

A 2012 GSR study conducted by Martin Reimann2 and colleagues at the University of California found that the game is true for brands. Customers get hot and (literally) sweaty when viewing a brand they’ve just fallen in love with, but show lower GSR responses for brands with which they’re in a long relationship.

Do your customers still go weak at the knees for your brand? GSR is one way to find out.

One way to spice things up for your customers is to introduce a new product, line or offer. But how far should it go? Should the new offer be only mildly surprising (like a trainers website that starts selling football boots), or extremely surprising (like a trainers website that starts selling high heels)?

The answer is, it depends on your customers’ arousal level. A 2014 study led by Theodore Noseworthy3 at York University in Canada found that when customers were in a high level of arousal (as measured by GSR) they preferred highly incongruous, surprising products.

At lower levels of arousal, this was too much, and customers preferred to be only moderately surprised.

GSR could be affected by concurrent body activities

Talking of surprise, one final GSR study – conducted by Sascha Topolinski4 and colleagues at the University of Wuerzburg, Germany – turned up a very surprising finding. Customers were shown adverts and then, a week later, given a GSR test.

Unsurprisingly, customers showed higher GSR arousal levels for products that had appeared in the adverts than similar products that had not; and this translated into higher “intention to purchase” ratings.

Surprisingly, though, the beneficial effect of adverts (as picked up by the GSR measure) was wiped out completely for people who had eaten popcorn or chewed gum while viewing them.

As this study shows, no matter how well you think you know your customers, well-conducted tests using GSR, and the other biometric measured covered in this blog series, can reveal surprising and valuable new insights.

And with many years of experience in biometric research, we at Endless Gain are both the pioneers and the masters of understanding and analysing human emotions while they interact with your eCommerce site.


[1] Bagchi, R., & Cheema, A. (2012). The effect of red background color on willingness-to-pay: The moderating role of selling mechanism. Journal of Consumer Research, 39(5), 947-960.

[2] Reimann, M., Castaño, R., Zaichkowsky, J., & Bechara, A. (2012). How we relate to brands: Psychological and neurophysiological insights into consumer–brand relationships. Journal of Consumer Psychology, 22(1), 128-142.

[3] Noseworthy, T. J., Di Muro, F., & Murray, K. B. (2014). The role of arousal in congruity-based product evaluation. Journal of Consumer Research, 41(4), 110.

[4] Topolinski, S., Lindner, S., & Freudenberg, A. (2014). Popcorn in the cinema: Oral interference sabotages advertising effects. Journal of Consumer Psychology, 24(2), 169-176.