Space & Innovation

Will it Hurt? Uncertainty Is Worst of All, Says Study

Not knowing if a decision will provoke pain is more stressful than correctly anticipating the outcome, even when that outcome is very painful.

Not knowing if a decision will provoke pain is more stressful than correctly anticipating the outcome, even when that outcome hurts like hell, according to a study released Tuesday.

Moreover, experiments with volunteers receiving electric shocks showed, the greater the stress the better subjects were at reading available clues to figure out the right response.

"People whose stress tracks uncertainty more accurately are better at predicting when they're going to get a shock," Archy de Berker, a scientist at the Institute of Neurology at University College London and lead author of the study, told AFP.

Tears Under The Microscope: Photos

Published in Nature Communications, the research suggests that stress - which corresponds to the activation of specific chemicals in the brain - can help us navigate risk in some situations.

Scientists have long understood that uncertainty, in itself, can cause anxiety.

Classic experiments with rats subjected to arbitrary electric shocks showed that stress levels dropped when the animals were able to anticipate or control the timing of the jolts.

The same applies to people.

But previous research mostly compared our reactions to total unpredictability or total control, and didn't examine different degrees and kinds of uncertainty we experience in everyday life.

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Facing a crucial job interview, for example, most folks will be more relaxed if they feel sure of the outcome, one way or the other.

"The most stressful scenario is when you really don't know - it's the uncertainty that makes us anxious," said co-author Robb Rutledge, a researcher at the Max Planck Centre for Computational Psychiatry and Ageing Research at University College London.

To better explore this middle ground, de Berker and colleagues devised a clever set of experiments in which 45 subjects, looking at images of two rocks on a computer screen, were repeatedly asked whether a snake lay hidden under one of them.

If there were a snake, the subjects - even if they guessed correctly - would receive a painful electric shock on the back of the hand, roughly equivalent to a wasp's sting, de Berker said.

They were asked the question several hundred times over the course of the experiment.

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Using complicated mathematical models, the scientists created patterns that gave the volunteers some clues.

These patterns, in fact, reflected distinct types of uncertainty, some random and others more-or-less predictable based on accumulated experience.

"Our experiment allows us to draw conclusions about the effect of uncertainty on stress," de Berker said.

"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."

The researchers tracked stress levels by measuring changes in pupil diameter, a proxy for the release of noradrenaline in the brain, and through questionnaires.

Surprisingly, they found that getting a shock you correctly guessed is coming is about as stressful as NOT getting a shock when you DID expect one.

"It seems as if the shock and the uncertainty have roughly equal roles to play in the stress people experienced," de Berker added.

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The fact that subjects with higher anxiety levels performed better in the snake/no-snake guessing game suggests that stress - over the course of human evolution - may have given humans an edge in the struggle to survive.

"The appropriate stress responses might be useful for learning about uncertain, dangerous things in the environment," co-author Sven Bestmann, also of University College London, noted in a press statement.

The study can be consulted at

To appreciate art is to have an emotional response to a new experience. For Dutch photographer Maurice Mikkers and his project,

Imaginarium of Tears

, in some ways, his art is emotion. For his work, Mikkers captured tears and photographed them as they appeared under a microscope. With each one, he also cataloged the story behind it, in other words what led his project's participants to tear up. This slide, for example, shows a tear resulting from sadness. Tears may seem like an unusual art subject until you see the results of Mikkers' work. "Tears are unique. They are beautiful, and they are art," Mikkers

told a TEDx audience at an event in Amsterdam last year


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So why tears? While working on a photo for another project in his

Micrograph Stories

series, a study in what everyday substances look like under a microscope, Mikkers bumped into a table and a tear formed as a result of the pain, the same tear in this slide. What Mikkers saw was "like a little planet," and the crystalline complexity of that one drop fueled more tears and more photos.

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As Mikkers explains, he advanced his project by collecting his own tears and then transitioning to experimenting with friends, inviting them over and giving them options to choose how they teared up. They could choose cutting onions, eating hot peppers, looking into a fan or crying as a result of an emotional response. A micropipet captured each tear, and then that tear was placed a small slide, allowing time for it to crystallize and form the patterns seen here. Here is a tear collected from a subject who had been cutting white onions.

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People tear up for different reasons in a number of different contexts. In fact, there are three different kinds of tears. The first type are called basal tears. Basal tears are the moisture that should always be present in our eyes, keeping them lubricated and protecting them from irritants. This photo shows an example of a basal tear, taken from a subject who looked at a fan for a few minutes.

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After basal tears come reflex tears, which as the name implies are a reaction to an outside stimulus. Anyone who has ever had sand in their eyes, chopped white onions or consumed a hot pepper, as was the case with the subject who provided the tear for this photo, knows what it's like to have teary eyes as a result of the irritation.

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Emotional tears are the final type. If someone feels happiness, sadness, fear, pain or pleasure, the teary response might be reflexive, as anyone who has fought to hold back tears can attest, but it is the result of an internal stimulus. As Mikkers notes, all tears contain the same basic compounds, water, lipids, glucose, sodium and more. Emotional tears have a few added ingredients, however, specifically prolactin, adrenocorticotropic and leucine enkephalin, which is an endorphin and natural painkiller. This photo captures a tear of happiness.

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Try as anyone might to find one, there is no relationship between the type of tear and the crystalline pattern that results in each image. This photo captures a tear of frustration.

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Whether we know it or not, we all produce an average of 10 ounces of tears per day and 30 gallons a year,

according to TED Ed's Alex Gendler


A 2011 study (PDF)

on crying episodes found that women cry an average of 1.3 times per month, while men generally cry about 1.3 times per month. The tears themselves are fleeting, as are the emotions of the subjects who produced though, but the patterns that emerge under Mikkers' microscope leaves a lasting impression. Combining the art with the stories that come with each tear, each photo carries its own gravity, just like a little planet. This tear was captured from a subject who had to say goodbye.

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