Anxiety can play havoc with your perception of the world BSIP/UIG/Getty

Anxious people perceive the world differently. An anxious brain appears to process sounds in an altered way, ramping up the expectation that something bad – or good – might happen.

There’s no doubt that some degree of anxiety is vital for survival. When we learn that something is dangerous, we generalise that memory to apply the same warning signal to other, similar situations to avoid getting into trouble.

If you’re bitten by a large, aggressive dog, for instance, it makes sense to feel slightly anxious around similar dogs. “It’s better to be safe than sorry,” says Rony Paz at the Weizmann Institute of Science in Rehovot, Israel.


The trouble begins when this process becomes exaggerated. In the dog bite example, a person who went on to become anxious around all dogs, even small ones, would be described as overgeneralising.

Overgeneralisation is thought to play a role in post-traumatic stress disorder and general anxiety disorder, a condition characterised by anxiety about many situations, leaving people in a state of near-constant restlessness. A study carried out by Paz suggests that overgeneralisation is not limited to anxious thoughts and memories – for such people the same process seems to affect their perception of the world.

Money problems

Paz and his colleagues played audio tones to 28 people diagnosed with generalised anxiety disorder. In the first round of the experiment, each volunteer was given a set amount of money. Every time they heard one of two tones, a sum was either deducted from or added to their pot. All participants quickly learned which tone was associated with financial loss and which with gain.

Later, the volunteers were played a range of subtly different tones, as well as the two original ones. This time the tones were no longer linked to monetary loss or gain.

In past experiments, Paz says he has found that people who are not anxious readily distinguish familiar tones from new ones. But his volunteers with anxiety struggled, and made around twice as many mistakes.

Even though money was no longer at stake, the anxious group appeared to overgeneralise their unpleasant memories of past loss so that it affected their perception of the sounds. Surprisingly, the volunteers made the same mistakes when trying to distinguish the tone associated with winning money.

Set up for a fall

All volunteers had normal hearing and memory – they just interpreted the sounds differently. “People with anxiety have an altered perception of the world,” says Paz.

Although the experimental set-up might seem artificial, it allowed the researchers to test the effects of learning a new association – one that was not coloured by previous experience in a real-world setting.

Liat Levita at the University of Sheffield, UK, thinks that overgeneralising positive experiences could end up adding to a person’s anxiety, because they stand to be extremely disappointed by a negative outcome.

In other experiments, Paz’s team used fMRI brain scans to compare the brain activity of people with and without anxiety problems while they were learning to associate tones with a loss or gain. The second group had greater levels of anxiety in the anterior cingulate cortex – a region of the brain linked to both anxiety and learning. They also had more activity in the part of the brain that processes sounds.

Levita hopes the results could eventually be used to design better treatments for anxiety disorders. “Maybe we have to tackle the abnormal perceptual process first,” she says. A neurofeedback training programme that helps people realise when their brains are overreacting might be useful, she suggests.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2016.01.023