Perception depends on objective and subjective interdependent factors, and that its relative importance could vary. Variation starts mainly from the subject, who-according to his relation with the medium-isolates the dominant forms from the background. In this way, the object's aspect depends on the needs of the subject.

Psychology, established as a science in Germany between 1870 and 1880, considered the analysis of the mind's basic elements its main task.

Two principal trends dominated the new science:

a) Watson's CONDUCTISM (or Behaviorism), that analyzed human behavior in terms of stimulus-response. ..THIS PROVES HE SCREAMS BECAUSE IT HURTS.

and

b) STRUCTURALISM, of Titchener, Wundt and Ebbinghaus, that divided the subconscious into independent elements detached from values.

For Behaviorism the conscience did not exist and for Structuralism the whole was a simple sum of parts.

In 1912 Wertheimer, Kohler and Koffka, protested against behaviourism and structuralism and thus founded gestalt psychology, to put an end to phenomena's atomisation...

They met at the University of Frankfurt and agreed that trying to understand existing phenomena (subject, object, medium) was no good unless they were seen as a complex whole, interdependent and interrelated.

Gestalt psychologists, who began studying perception, soon embraced other fields of research, such as learning, social behavior and thought.

Sigmund Freud (1856-1939), Viennese neuro-pathologist physician, had already published Studies on Hysteria (1895), The inter- pretation of Dreams (1900), Psychoanalysis of Everyday Life (1901), Three Essays on the Theory of Sexuality (1905), Five lessons on Psychoanalysis (1910) and Totem and Taboo (1912).

In 1896 he invented PSYCHOANALYIS, in 1900 discovered the SUBCONSCIOUS, in 1907 he encountered Jung and Ferenczi, but 1921 he severed relations with Jung.