Scientist develops robotic technique to understand why people hear ‘their dead’

According to studies, five to ten per cent of all people, including healthy ones, hear voices related to their dead ones.Scientists have no idea what happens in the brain when people hear these “auditory hallucinations.”

Now, neuroscientist Pavo Orepic from the University of Geneva is claiming to have designed a robotic theory that can solve the scientific puzzle.

Who experiences these hallucinations?

It is generally assumed that these hallucinations are experienced by not just those having psychiatric disorders. However, according to studies, 70 per cent of people diagnosed with schizophrenia generally hear such voices.

Schizophrenics don’t make good subjects for experiments related to hallucinations since they consume drugs and medicines that might have side effects, complicating the results.

Why do these hallucinations occur?

Hallucinations occur when an individual’s sensory impressions don’t match with their brain’s expectations.

Some investigations also reveal hallucinations might occur when the brain has been conditioned by previous impressions and interprets sensory perceptions incorrectly as a result.

New robotic technique

Orepic has now designed an experiment which might trigger the above two mechanisms simultaneously.

As a part of the experiment, some blindfolded people were asked to press a lever in front of them. As they did so, a robotic arm touched them on their back.

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With some practice, their brain started to perceive that it was their own hand which was touching them in their back.

After some practice, the experiment underwent a slight change.

Now, as the participants touched the lever, the robotic arm touched them after a slight delay.

This led the brain to think someone else was present there. “Now the brain explains that delayed sensory feedback as someone else being present and touching them in the back,” Orepic said.

In the next part of the experiment, the subjects were made to hear noises into which they had mixed either very soft voices – sometimes the subjects’ own, sometimes someone else's – or no voice at all.

Surprisingly, it turned out that those having experienced the ‘delayed touch experiment’ were more likely to hear voices in the noise even if no voice had been mixed in.

“Our study confirms that the mechanisms behind the hallucinations are actually in everyone’s brain,” Orepic says.

“But for some reason, some people are more susceptible to them than others,” he adds.

(With inputs from agencies)