Why we make the worst decisions under time pressure - new study

Researchers from the University of Melbourne have found that stress alone does not always prevent people from making the right decisions. However, when combined with severe time constraints, it drastically reduces their quality and makes people more prone to mistakes. The results of the study are published in the journal Communications Psychology.

The state of acute stress is familiar to many people - it is experienced before exams, job interviews or when working under deadlines. Previous research has shown that stress negatively affects basic cognitive functions such as memory. But it remained unclear how it affected more complex processes like decision-making and problem solving.

To find out, the researchers conducted a series of controlled experiments involving 42 people. Participants were put into a state of acute stress, similar to the experience before a job interview, using the so-called Trier Social Stress Test. It involved preparation and public speaking without notes in front of 'experts', as well as complex maths tasks with punishment for mistakes.

To confirm the stress response, the volunteers had their saliva cortisol levels, pupil dilation, sweating and subjective feelings measured. All indicators confirmed that the participants were indeed under severe stress.

The subjects were then asked to perform a series of 72 complex decision-making tasks under constraints - for example, to determine whether a set of items with the right value could be selected without exceeding the allowable weight. Such tasks mimic real-life situations, such as shopping on a tight budget or planning tasks when time is short.

Unexpectedly, it turned out that stress alone had almost no effect on the accuracy of decisions - even in the most difficult tasks. However, this changed when time pressure was added to stress. Under these conditions, participants were more likely to rush, paid less attention to detail, and were significantly more likely to answer "no" even when the correct answer was positive.

As a result, the average quality of decisions decreased by about 5 per cent. In some cases - when the correct solution actually existed - accuracy fell from 83% to 57%, only slightly above the level of random guessing.

The authors note that it was the combination of stress and lack of time that proved most damaging. They say stress can increase pessimism and interfere with recognising profitable opportunities. Now the team is conducting additional research to confirm the findings and find ways to reduce the negative effect.

The scientists emphasise: stress is a complex phenomenon that can sometimes even improve certain cognitive functions. But under conditions of tight deadlines, the risk of erroneous decisions increases significantly.