Born in Prague, Maz Wertheimer studied law and philosophy at the University of Prague, and psychology under Stumpf and Kulpe. Best known for his explanation of the “phi phenomenon” (e.g., the apparent motion made by flashing lights in sequence), Wertheimer was a founder of Gestalt psychology.
In 1910, on a train ride from Vienna to Germany, Wertheimer noted that it’s possible to perceive motion when none exists. So interesting was this new idea that when the train stopped in Frankfurt, Wertheimer got off, bought a toy stroboscope which flashes pictures to make them look like they are moving, and checking into a hotel to experiment with his insight.
Wertheimer followed up his informal exploration with formal experiments using a tachistoscope. He found that when two flashes of an image are 200 milliseconds apart they are perceived as separate images, and at 30 milliseconds the images appeared simultaneous.
Although Wundt had maintained that apparent movement was a function of eye movement, Wertheimer noted that eyes can’t move in two directions at once. His solution was to propose an isomorphic model. That is, according to Wertheimer, the movement occurs in the brain. He held that the mind comes with preset principles of organization it uses to interpret sensations. For Wertheimer apparent motion was evidence that people don’t respond to isolated segments of sensation but to the whole (Gestalt) of the situation.
Gestalt principles of perceptual organization include proximity, similarity, continuity, and pragnanz (literally, good form). Using visual illusions, Gestalt psychologists were able to show that the perceptual models of the day were inadequate. Extending that view, they proposed that people perceive and think in nonlinear ways, actively influence perception, and use insight as well as trial and error learning.