Scientists have caused auditory hallucinations in mentally healthy people

Researchers from the Federal Polytechnic School of Lausanne and the University of Savoy Mont Blanc have found that under certain conditions it is possible to cause auditory hallucinations in mentally healthy people. The experiments used robotic assistance to induce auditory-verbal hallucinations in volunteers.

During the experiments, scientists used robotic assistance to induce auditory-verbal hallucinations (AVH) in volunteers. This allowed us to study in more detail how the brain can create such experiences. It is noted that AVH is often associated with various mental disorders.

The researchers focused on AVH triggers, the perception of voices or sounds without a visible source. Previous studies have linked these hallucinations to failures in the brain's self-control, but the new study provides unique data on the cause of these experiences in a controlled laboratory environment.

To conduct experiments, a team of researchers has developed an innovative method combining voice perception and sensorimotor stimulation. The participants, experiencing a variable delay when pressing the button, heard a combination of "pink noise" and random fragments of voice through headphones.

The results were surprising: some participants not only felt the touch, but also claimed to hear voices despite their absence. The effect of the appearance of voices was more vivid when the voice of another person preceded the voice of the participant, and when there was a delay between pressing the button and touching the hand.

These results confirm hypotheses about hallucination triggers, pointing to the participants' difficulties in monitoring the surrounding space and the impact of strong beliefs about events. The study focuses on "hearing voices", which distinguishes it from previous studies conducted on patients.

This work not only expands our understanding of how the brain creates hallucinations, but also helps in the search for new methods of studying mental disorders.

What are auditory hallucinations?

The phenomenon of auditory hallucinations turns out to be much more widespread than we could have imagined.

Auditory hallucinations can manifest in different forms. The most common are verbal, when a person hears voices. These voices can occur both in people with mental disorders and in those who do not have diagnosed mental problems. Interestingly, their sources can be both external sounds and internal mental events. Auditory verbal hallucinations are most often associated with schizophrenia, but they can also occur in absolutely healthy people.

The second type of auditory hallucinations is hearing sounds or noises. Here imagination reaches incredible heights, and people can experience a variety of auditory sensations, ranging from music to animal cries or background noises. The volume of these sounds can vary from quiet to loud.