Gestalt psychology as defined by the Encarta Dictionary: English (U.K.), a branch of psychology that treats behaviour and perception as an integrated whole and not simply the sum of individual stimuli and responses.
Gestalt psychology emerged in Germany as a response against Wilhelm Wundt’s structuralism. Later the gestalt psychologists criticized the reductionist approach of behaviorists like Watson. The school was officially founded in the 1920s, but it all began around 1910 by Max Wertheimer (1880 – 1943) who was a Czech-born Jewish teacher. He produced a paper called apparent motion which is about visual illusions. Apparent motion is what one perceives when still images are being rapidly moved in a sequence, like watching a movie. Wertheimer discovered that, the perception of the movement as a whole was very different from the perception of the images being viewed individually as still images. This is where gestalt psychology originated from. The idea being is that the whole is different from the sum of its parts.
Wertheimer worked with two research assistants Kurt Koffka (1886-1941) and Wolfgang Kohler (1887- 1967) who were classed as cofounders of gestalt psychology because they were so closely linked with the development of this school of psychology. Each saw objects as things within an environment, and took into account all of the elements of the whole. This gestalt approach was intended to define principles of perception. They also made the connection through experience that a subjective experience and it’s underlying neural happenings have structures
References: Hergenhahn,B.R.: An Iroduction to the History of Psychology Sixt Edition Rock,I. and Palmer,S. Article: The Legacy of Gestalt Psychology, Scientific American December 1990