People are quicker to jump to the worst conclusion when they are stressed, a new study suggests.
that when people are under stress, they reach undesirable conclusions based on weaker evidence than when relaxed.
In experiments, participants who were anticipating a stressful event increased their attention toward negative stimuli in a computerised task.
‘Many of the most significant choices you will make, from financial decisions to medical and professional ones, will happen while you feel stressed,’ said study author Professor Tali Sharot at UCL.
‘Often these decisions require you to first gather information and weigh the evidence.
‘For example, you may consult multiple physicians before deciding on a best course of medical treatment.
We wanted to find out, does feeling stressed change how you process and use the information you gather?
For the study, 91 volunteers were recruited to play a categorisation game, in which they could gather as much evidence as they wanted to decide whether they were in a desirable environment (associated with rewards) or an undesirable environment (associated with losses).
The categorisation game, called factory task, displays an animated sequence of TVs and smartphone passing along a conveyor belt.
The participants’ aim was to accurately determine whether they were in a phone factory (a factory that produces phones most of the time), or a TV factory (one that mostly produces TVs).
For each round, each participant was ‘invested’ in one factory. On trials where they happened to be in that ‘desirable’ factory they gained points, while on trials in which they were in the other ‘undesirable’ factory they lost points.
The participants were incentivised for accuracy, in the form of a cash payment of an undisclosed amount.
On trials in which the participants were in a desirable environment (desirable factory) they would observe mostly items that they knew will gain them a reward.
On trials in which the participants were in a UNdesirable environment (UNdesirable factory) they would observe mostly items that they knew will cause them to lose money.
They never knew for sure whether they were in a desirable or undesirable environment because it is difficult to tell.
So for example, if you were a participants in the experiments, you would be told: ‘Every time you visit a telephone factory (desirable environment) you will receive a reward, and every time you visit a TV factory (undesirable environment) you will lose a reward.’
Phone factories produce mostly phones and TV factories produce mostly TVs, but sometimes a TV factory can produce a phone and vice versa.
Now the study begins. On the first trial, unbeknownst to you, the computer decides you are in a TV factory and shows you: TV, TV, phone, TV, phone, phone, phone, etc.
Are you in a desirable environment (phone) or an undesirable (TV)? if you are unsure you may want to see some more items the factory produces to make your decision.
Before playing the game, 40 of them were told they had to give a public speech, which would be judged by a panel of experts, prompting them to feel stressed and anxious.
Under stress, the volunteers needed weaker evidence to reach the conclusion of being in the undesirable factory, the researchers found.
But the stress did not change the strength of the evidence needed to reach the conclusion they were in the desirable factory.
‘Our research suggests that under stress, people weigh each piece of evidence that supports undesirable conclusions more than when they are relaxed,’ said Professor Sharot.
‘In contrast, how they weigh evidence that supports desirable conclusions is not affected by stress.
‘As a result, people are more likely to conclude the worst is true when they are stressed.’
The experts point out that critical decisions are often made under threatening circumstances that elicit stress and anxiety.
Stress’s impact on mental and physical health can also hurt productivity and result in economic loss.
The study, published in the Journal of Neuroscience, suggests that evidence accumulation ‘is a flexible process which quickly adjusts to the environment’, the authors conclude.
‘We usually think of stressful situations as a hindrance to our decision-making process,’ said study author Laura Globig at UCL.
‘But the pattern of learning we have uncovered may counterintuitively be adaptive, because negative beliefs may drive people to be extra cautious when in threatening environments.’
