Scientists find how we see ghosts -- 'it's all in the mind'

Do ghosts really exist? Well, if scientists are to be believed, they do but "in the mind" only.

The researchers at the University College in London have found that that when people gaze around in a poorly lit context, it can fool their brains into seeing things that are not really there.

"The context surrounding what we see is all important -- sometimes overriding the evidence gathered by our eyes and even causing us to imagine things.
"Illusionists have been alive to this phenomenon for years. When you see them throw a ball into the air, followed by a second ball, and then a third ball which 'magically' disappears, you wonder how they did it.

"In truth, there's often no third ball -- it's just our brain being deceived by the context, telling us that we really did see three balls launched into the air, one after the other."

"This could also be why monsters tend to lurk in the shadows. In shadows many things are seen vaguely (rather than clearly), thus tending to trigger the filling in," 'The Daily Telegraph' quoted lead researcher Prof Li Zhaoping as saying.
In their study, 18 observers were asked by the team to concentrate on the centre of a black computer screen.

Every time a buzzer sounded they pressed one of two buttons to record whether or not they had just seen a small, dim, grey "target" rectangle in the middle of the screen. It didn't appear every time, but when it did it was displayed for just 80 milliseconds (80 one thousandths of a second).

"People saw the target much more often if it appeared in the middle of a vertical line of similar looking, grey rectangles, compared to when it appeared in the middle of a pattern of bright, white rectangles. They even registered 'seeing' the target when it wasn't actually there.

"This is because people are mentally better prepared to see something vague when the surrounding context is vague. "It made sense for them to see it -- so that's what happened. When the target didn't match the expectations set by the surrounding context, they saw it much less often," said Prof Zhaoping.
The results of the study have been published in the 'PLoS Computational Biology' journal.