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A autokinetic illusion autokinetic effect is a phenomenon of human visual perception in which a stationary, small point of light in an otherwise dark or featureless environment appears to move. It was first recorded by a Russian officer keeping watch who observed illusory movement of a star near the horizon. It presumably occurs because motion perception is always relative to some reference point. In darkness or in a featureless environment there is no reference point, so the movement of the single point is undefined. The direction of the movements does not appear to be correlated with the involuntary eye movements, but may be determined by errors between eye position and that specified by efference copy of the movement signals sent to the extraocular muscles.
The amplitude of the movements is also undefined. Individual observers set their own frames of reference to judge amplitude (and possibly direction). Because the phenomenon is labile, it has been used to show the effects of social influence or suggestion on judgements. For example, if an observer who would otherwise say the light is moving one foot overhears another observer say the light is moving one yard then the first observer will report that the light moved one yard. Discovery of the influence of suggestion on the autokinetic effect is often attributed to Sherif (1935), but it was recorded by Adams (1912), if not others.
Autokinesis and Countermeasures for Pilots
A stationary light stared at for 6 to 12 seconds in the dark will appear to move. This phenomenon can cause considerable confusion for pilots, especially those flying in formation or rejoining on a refueling tanker at night.
To prevent, or overcome this phenomenon, the pilot should:
- Shift their gaze frequently to avoid prolonged fixation on light sources.
- Attempt to view a target with a reference to stationary structures or landmarks.
- Make eye, head, and body movements to eliminate the illusion.
- Monitor the flight instruments to prevent or resolve any perceptual conflict.
Alleged sightings of UFOs have also been attributed to the autokinetic effect's action on stars or planets.
- Adams, H. F. (1912). Autokinetic sensations. Psychological Monographs, 14, 1-45.
- U.S. Air Force (2000). Flying Operations, Instrument Flight Procedures. Air Force Manual 11-217. Volume 1, 29 December 2000.
- Fundamentals of Aerospace Medicine, second edition, by Roy L. DeHart. Port City Press, 1996.
- Sherif, M. (1935). A study of some social factors in perception. Archives of Psychology, 27(187) .
- nl:Autokinetisch effect
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