According to the Columbia Electronic Encyclopedia, associationism theory explains that all consciousness is the result of the combination, in accordance with the law of association, in psychology, a connection between different sensations, feelings, or ideas by virtue of their previous occurrence together in experience. Although Aristotle and Plauto are known to start the idea of association, the concept of association entered contemporary psychology through the empiricist philosophers John Locke, George Berkeley, and advanced by James Mill.
John Stuart Mill
Laws of Association
Law of Similarity – the experience or recall of one object will elicit the recall of things similar to that object.
Law of Contrast – the experience or recall of one object will elicit the recall of opposite things.
Law of Contiguity – the experience or recall of one object will elicit the recall of things that were originally experienced along with that object.
Law of Frequency – the more frequently two things are experienced together, the more likely it will be that the experience or recall of one will stimulate the recall of the second.
"Associationism represents a school of thought that suggests that most higher-order mental functions arise as a consequence of linked ideas in the brain."