There are thousands of recordings on platforms like YouTube of acoustic stimuli used to improve cognitive processes. Extremely popular are the so-called binaural beats, or synchronous rumblings. In a nutshell, this form of brain stimulation involves delivering tonal sounds of different frequencies to each ear, which, when interacting, produce the sensation of binaural rumbling. The frequencies are chosen so that their difference reflects the desired frequency of the brain waves. People around the world listen to such prepared recordings in their own homes when they study or when they perform other cognitive activities.

For two years, Prof. Michal Klichowski and Dr. Agnieszka Kruszwicka (neuropedagogues from the Department of Educational Studies) and Prof. Andrzej Wicher and Prof. Roman Golębiewski (acousticians from the Department of Acoustics of the Faculty of Physics) carried out an experiment under natural conditions that showed that such forms of acoustic brain stimulation are counterproductive – instead of helping cognitive tasks, they dramatically impair cognitive performance. In this experiment, 1,000 people performed difficult cognitive tasks in their own homes, in some cases listening to specific sounds. These included a variety of sounds, such as music, noise, but also just binaural beats. They found that listening to binaural beats significantly worsened performance on these tasks. This is the first study on the use of binaural beats at home, so further work is needed. However, it can already be concluded that applying binaural beats to oneself may not only not help, but also harm. This could be the result of poorly chosen frequencies or too much exposure time. It is also possible that there is some neuronal mechanism behind such an inverted effect of binaural beats, which is not yet understood. Researchers at the Center for Cognitive Neuroscience have come up with several hypotheses.

One of them indicates that binaural beats somehow interfere with brain waves and lower their frequency, so that brain activity is mismatched to the task at hand. The second hypothesis refers to the fact that most of our daily cognitive tasks are highly varied, so it is not advisable to modulate only one frequency when performing them. Binaural beats thus may temporarily block brainwave frequencies that are appropriate for performing a particular part of the task.
Prof. Michal Klichowski, director of the Center

Prof. Michal Klichowski, director of the Center for Cognitive Neuroscience

An article with the results of this project has just been published in the journal Scientific Reports, one of the Nature Portfolio journals, and is available at the link:
https://www.nature.com/articles/s41598-023-38313-4.pdf