Color phi phenomenon

It is a perceptual illusion described by psychologists Paul Kolers and Michael von Grünau[1] in which a disembodied perception of motion is produced by a succession of still images.

The classic color phi phenomenon experiment involves a viewer or audience watching a screen, upon which the experimenter projects two images in succession.

Philosopher Daniel Dennett utilizes the color phi phenomenon in his argument against a philosophy known as Cartesian materialism.

[2] Psychobiologist John Staddon contrasts a simple "new behaviorism" interpretation of color phi with Dennett and Kinsbourne's account.

The basic idea is that because of well-known processes such as lateral inhibition, the internal states created by the two stimuli are identical, hence are so reported.

What is actually shown: First a blue dot is shown at the top of the screen, followed by a period of blank screen. Finally a red dot is shown at the bottom of the screen.
Subjects report seeing a dot that moves from the top to the bottom. The dot changes color midway through its path.