What is the phi phenomenon? What was its importance in the formation of the Gestalt school of psychology?
In 1910, Max Wertheimer got an idea when he was on his way in a train to the Rhineland from Vienna. He described his idea as sensual stimulations are not organized but our perceptions were. It simply means that our perceptions of the world were very different then the feelings (sensations) which make them. To understand this, he experimented with a toy stroboscope and a tachistoscope.
Stroboscope is a device that is used to show pictures in such a way that they appear to move. Tachistoscope is also a device which can emit light on and off in the fraction of a second. With the help of tachistoscope, he flashed two lights successively and noted that if the time period between two flashes is large that is about 200 miliseconds then the observer can easily notice the on and off of two lights.
When the time period is small that is 30 milliseconds then the two lights appears to be on simultaneously. If the time is little bit more that is 60 milliseconds then it looks like one light is moving from its place to other place. This obvious movement of light was named by Wertheimer as phi phenomenon.
This phi phenomenon was taken as beginning of the Gestalt psychology. Wertheimer communicate this phenomenon to logical system of descriptive principles that considered its place in psychology.