Brain’s visual system adapts to ignore frequent distractions, study finds

The human brain can learn through experience to filter out disturbing and distracting stimuli—such as a glaring roadside billboard or a flashing banner on the internet. Scientists at Leipzig University and Vrije Universiteit Amsterdam have used electroencephalography (EEG) to show that early visual processing in humans changes with repeated exposure.

Distractions are often easier to ignore after we have encountered them multiple times. This learned suppression is an important component of the human visual system, which is otherwise strongly influenced by voluntary attention control.

In a series of EEG experiments involving 24 female and male participants, the researchers investigated how learning influences attention to prominent distracting stimuli when these distractions frequently occur in specific locations.

The research is published in The Journal of Neuroscience.

“We found consistent evidence that learning alters the early responses of the visual system to these stimuli,” says Dr. Norman Forschack from the Wilhelm Wundt Institute of Psychology at Leipzig University, one of the study’s authors.

In the experiments, participants were asked to locate a specific target object—for example, a green circle among green diamonds. As part of the task, a distracting stimulus—such as a red diamond—was frequently placed in the same position.

Analysis of brain activity revealed that, over time, the brain began to suppress that position within the very first moments of visual processing. Participants also performed significantly better in locating the target object when the distracting stimulus appeared in the learned position, compared to when it appeared elsewhere.

“These findings show that our brain doesn’t just react automatically to striking stimuli, but can also learn through experience to filter out distractions efficiently,” explains Forschack. “Interestingly, we also observed reduced visual processing for target stimuli when they appeared in the position where the distractor had been frequently shown,” he adds.

It remains unclear how this habitual attenuation of visual processing works in everyday life—for example, for commuters who repeatedly travel the same routes. According to the researchers, consistent design of roads and traffic environments could be beneficial for road safety.

Dock Duncan of Vrije Universiteit Amsterdam, the study’s lead author, concludes, “It is clear that people automatically recognize familiar user interfaces or textbook chapter layouts and find these useful, and that this effect is already reflected in basic visual processing.”