Voluntary change of pupil size works against stress
Published: Tuesday, Oct 31st 2023, 09:50
Updated At: Wednesday, Nov 1st 2023, 00:55
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People can gain control over their state of arousal by deliberately changing the size of their pupils. This is shown in a new study by researchers at the Swiss Federal Institute of Technology in Zurich (ETH Zurich).
This finding has enormous potential for treating stress and anxiety disorders, the researchers wrote in the study, which was published Monday evening in the journal Nature Human Behaviour.
First, the researchers taught a group of 27 test subjects to control their pupils by breathing or visualizing threatening situations. The subjects sat in front of a screen that recorded how well they succeeded.
Feedback crucial
Some of the test subjects were shown the result on the screen. This feedback from the screen, known in science as biofeedback, turned out to be crucial for this process: subjects who received real-time feedback about their pupil size were better able to control their arousal state and pupil size, according to the study.
Pupil feedback allowed subjects to identify the relaxation and activation techniques that worked best for them, ETH Zurich said in a statement.
Heart rate lower
In a second step, the researchers investigated what influence this change in pupil size had on heart rate. According to the study, the pulse of the subjects who were able to better control their pupils because of the feedback decreased and increased more than the pulse of the subjects who did not receive feedback. In addition, the effect on pulse was stronger at the end of the pupil control training than at the beginning.
To use this method, commercially available VR glasses could be used, according to ETH Zurich. These could provide real-time feedback on pupil size, according to the university. The researchers have already founded a spin-off to bring this technology to market.
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