The reason people see ghosts

New research by Chinese neuroscientists indicates that local problems in brain activity are the biggest cause of ghost sighting.

Ghost sighting may result from malfunctions in brain activity.(Photo: Mirror.)

With the assumption that most cases of ghosts are visual illusions instead of actually seeing dead people, the research team is headed by Professor Wang Wei of the Shanghai Institute of Biology that finds most cases occurring when the brain misunderstand the signals coming from the eyes, South China Morning Post reported yesterday.

Images appear in the brain after a large number of photons (light quantum particles) are collected by millions of receptors in the retina. Next, they are converted into electrical signals, compressed and transmitted along the nerve to the visual center of the brain. Previous research has shown that small pieces of information lost during transmission can contribute to visual illusion.

Wei's team asked volunteers to look at the image of Pinna illusion (the illusion of two circles moving in opposite directions when the observer approached or moved away from the image). This illusion was created in the 1990s by Dr. Baingio Pinna, a visual scientist and painter in Italy. Researchers re-measured volunteers' brain activity by functional magnetic resonance imaging ( fMRI).

Next, volunteers were asked to sit still when the circles on the motion card and the research team analyzed to find out if there were any important differences in the way their brains responded to stimulation.

The results initially did not help to draw conclusions and did not meet the expectations of neuroscientists. They could not find any abnormality in the brain signal , showing the human brain handling visual illusions and real images in the same way.

However, the volunteer brain scan revealed only a portion of their visual center - the cortical area responsible for visual information - activated to process the raw visual signal. To clearly distinguish the real and fake images, volunteers need to activate another part of the brain called the middle temporal lobe, which evaluates and processes distance information.

This part was not activated when volunteers approached and moved away from the image. As a result, their brains failed to distinguish between changes in distance and changes in rotation when processing image signals from Pinna illusion observations. In other words, they experience temporary problems in the interaction between the eye and the brain.

Research by Chinese scientists indicates that the human brain still makes mistakes during its operation despite experiencing millions of years of evolution. The weakness of this type can easily make the brain misunderstand the meaning and lead to supernatural experiences like seeing ghosts.