THE AUTOKINETIC EFFECT

Over the years, a large number of UFO sightings have been found to be misidentifications of the planet Venus. In these cases, the location of the object in the sky, as described by the witness, exactly matched the known position of Venus at that time. An apparent discrepancy arises if the witness says the UFO was ‘moving’, because the actual motion of the planet would be so small as to be unnoticeable. But this can be explained in terms of the autokinetic effect – a well-studied quirk of human perception in which a stationary point appears to move around when seen against a dark or featureless background.

Optical illusions can make the brain think that stationary objects are moving