Associationism in philosophy refers to the idea that mental processes operate by the association of one state with its successor states. The idea was first recorded by Plato and Aristotle, especially with regard to the succession of memories. During the late 1700’s, members of the British Associationist School asserted that the principle applied to all or most mental processes.
The school developed very specific principles specifying how associations worked and even a physiological mechanism bearing no resemblance to modern neurophysiology. By the end of the nineteenth century, physiological psychology was so altering the approach to this subject that much of the older associationist theory was rejected.
Nevertheless, the everyday observation of the association of one idea or memory with another gives a validity to the notion. In addition, the notion of association between ideas and behavior gave some early impetus to behaviorist thinking. The core ideas of associationist thinking recur in some recent ideas on cognition, especially consciousness.
It is held that association is of objects not of ideas. It is between things thought of, between processes in the brain. The most natural way of accounting for it is to conceive of it as a result of the laws of habit in the nervous system, in other words, to ascribe it to a physiological cause.
Association thus results because when a nerve current has once passed by a given way, it will pass more easily by that way in future, and this fact is a physical fact. The important deduction is that the only primary or ultimate law of association is that of neural habit.