An uncertain electric shock can be more stressful than inevitable pain

29 March 2016

Knowing there is a small chance of getting a painful electric shock can lead to an increased level of stress than if you are certain you will be shocked, according to a study by University College London (UCL).

The study, which was funded by the Medical Research Council and published in Nature Communications, found that when subjects had a 50 per cent chance of receiving a shock, they were more stressed than when there was a 100 per cent certainty that they would definitely have an electric shock.

Results from this study indicated that stress may inform judgements of risk as people were also more calm when there was no chance they would receive a small shock.

There were 45 volunteers involved in the experiment, which saw them playing a computer game to turn over rocks that may or may not have snakes underneath them. They had to guess if the snakes would be there and if one was found, the contributor received a small, painful shock.

Over time they learned which ones did and didn't have snakes underneath and the odds changed throughout the experiment, greatly influencing the levels of the volunteers uncertainty.

Archy de Berker, lead author of the study from the UCL Institute of Neurology, said: "We saw exactly the same effects in our physiological measures - people sweat more and their pupils get bigger when they are more uncertain."

Posted by Jeanette Royston


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