René Descartes, the philosopher, had posed a serious question around 300 years ago, stating how can our mind be trusted considering the lack of the ability to separate illusion from reality.
The new study has found out that we can indeed trust our senses and draw clear demarcations of illusion from reality since our brain keeps are cord of the reality based on the past expectations and beliefs. Hallucinations are a direct result of the failure caused when the mind is not able to internally check the facts.
The new realm of study is an important step towards identifying the part of the brain which produces hallucinations and keeping them under check for treating schizophrenia and other psychiatric disorders.
THE EXPERIMENT AND THE FINDINGS
The experiment from 1890 at Yale University had already established how the world cannot be always perceived based on the findings. The experiment included the researchers to subject the volunteers with an image accompanied by a sound. The participants still heard the sound with the projection of the image even when the sound wasn’t played.
Hallucinations occur commonly like we sometimes hear our mobile phones ring even when they haven’t. This occurs because we expect our phones to ring so much that our brain hears it for us. This example indicates clearly how the origin of hallucinations occurs when the brain gives more importance to the beliefs and expectations than the evidence it is provided with.
THE NEW EXPERIMENT
Albert Powers along with his fellow psychiatrists at Yale University applied the 1890s experiment to the group of different people-
- Healthy people
- People who couldn’t hear voices, dealing with psychosis
- People with schizophrenia
- People who didn’t find the voices disturbing despite hearing regular voices, called psychics
The training began with each group for associating a checkerboard image with 1 KHz 1-second long tune. The team manipulated the intensity of the tone by increasing or completely removing it. The participants had to press the button on hearing it and use pressure for indicating how confident they were about hearing it.
A snapshot of the brain activity of the participants was taken by the researchers by using the magnetic resonance imaging scanners.
The schizophrenics and the psychics heard the absent tone five times more than the normal healthy people. Even when there was no tone, they were confident about hearing it. They even showed the abnormal activity of the neurons in the regions of the brain which monitored reality.
This indicated that the ideas and beliefs that we hold can overpower the reality. It also showed that the cerebellum is the major area trying to control the blurring lines between the facts and fiction.