Ghosts may be just a bug in the brain, say researchers belchonock/iStock

A 'bug' in the brain may be the cause of ghost sightings, say researchers. Paranormal activity may be due to a temporary breakdown of communication between the eyes and the brain.

Research published in Human Brain Mapping, describes how the brain can sometimes fail to register the difference between a rotating image and a static one; or optical illusions. The researchers used this information to infer that visions of ghosts may not be real, reports the South China Morning Post.

The researchers from the Shanghai Institute for Biological Sciences used optical illusions to discover this breakdown of communication. They had over a dozen volunteers look at the Pinna illusion; an optical illusion which uses two colours of concentric circle.

As the volunteers looked at the Pinna illusion, the image did not move. However, when they moved their heads back and forth toward it, the image began to appear as if it were moving.

Pinna Illusion
When moving toward and back from the Pinna illusion, the image appears to be moving. When staying still, the image appears still Aegaeus Mann/Flickr

Magnetic Resonance Imaging of the volunteers brains revealed differences between the two tests. When the image appeared to be moving, the medial superior temporal area of the brain was activated. This is the part of the brain which deals with moving images. When the volunteers remained still – and the image did not move – the section of the brain was not activated.

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The medial superior temporal area of the brain activated when the optical illusion was moving Human Brain Project

That means to say the brain could not accurately distinguish between an image which is real, and an image that is fake.

The researchers say that they experienced a temporary failure of communication from the eyes to the brain. This shows that the brain can still malfunction, even after years of evolution.

It is this malfunction which led the researchers to believe sightings of ghosts are not real. They say pieces of information lost along the way can result in optical illusions, and the brain cannot decipher whether what it is seeing is real or fake.

In 2015, expert parapsychologist Caroline Watt said that the study of ghosts will eventually disappear. She said that gradually, paranormal activity would be explained by neuroscience and psychology; just like the research from the Shanghai Institute of Biological Sciences.

Watt told New Scientist: "Even if we find that there is some paranormal experience that cannot currently be understood by physics, I would expect that it could become integrated so that we can make sense of these experiences in physical terms."