“Sorrow is better than fear. Fear is a journey, a terrible journey, but sorrow is, at least, an arriving.” So says Father Vincent in “Cry, the Beloved Country,” Alan Paton’s celebrated novel about South Africa. Share on Pinterest Which way to go? Not knowing the outcome can be tougher than the outcome itself. Now, research published in Nature Communications suggests that knowing that something bad is going to happen is better than not knowing whether it will happen or not. Findings show that a small possibility of receiving a painful electric shock causes people more stress than knowing for sure that a shock was on the way. Researchers from University College London (UCL), in the UK, enlisted 45 volunteers to play a computer game, which involved turning over rocks under which snakes might lurk. The aim was to guess whether or not there would be a snake. Turning over a rock with a snake underneath led to a small electric shock on the hand. As the participants became more familiar with the game, the chance of a particular rock harboring a snake changed, resulting in fluctuating levels of uncertainty.

Stress levels match levels of uncertainty An elaborate computer model measured participants’ uncertainty that a snake would be hiding under any specific rock. To measure stress, the researchers looked at pupil dilation, perspiration and reports by participants. The higher the levels of uncertainty, say the findings, the more stress people experienced. The most stressful moments were when subjects had a 50% chance of receiving a shock, while a 0% or 100% chance produced the least stress. People whose stress levels correlated closely with their uncertainty levels were better at guessing whether or not they would receive a shock, suggesting that stress may help us to judge how risky something is. Lead author Archy de Berker comments: “It turns out that it’s much worse not knowing you are going to get a shock than knowing you definitely will or won’t. We saw exactly the same effects in our physiological measures: people sweat more, and their pupils get bigger when they are more uncertain.” While many people will find the concept familiar, this is the first time for research to quantify the effect of uncertainty on stress. Coauthor Dr. Robb Rutledge notes that people who are applying for a job will normally be more relaxed if they know they either will or will not get the job. “The most stressful scenario,” he says, “is when you really don’t know. It’s the uncertainty that makes us anxious.”