Association of ideas, or mental association, is a process by which representations arise in consciousness, and also for a principle put forward by an important historical school of thinkers to account generally for the succession of mental phenomena. The term is now used mostly in the history of philosophy and of psychology. One idea was thought to follow another in consciousness if it were associated by some principle. The three commonly asserted principles of association were similarity, contiguity, and contrast, numerous others had been added by the nineteenth century. 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.
Everyday observation of the association of one idea or memory with another gives a face 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 thought on cognition, especially consciousness.
Early theory
The associationist theory is anticipated in Plato's Phaedo, as part of the doctrine of anamnesis. The idea of Simmias is recalled by the picture of Simmias (similarity) and that of a friend by the sight of the lyre on which he played (contiguity). But Aristotle is credited with originating associationist thinking based on this passage:
Both Thomas Hobbes and John Locke are accredited for the initial study of theory of association. The basis of Hobbes's theory of association is that motion is what rules and attributes to mental activity. Hobbes tells us that the associations which already exist in our minds are what rule our flow of imaginations. s: " But as we have no imagination, whereof we have not formerly had sense, in whole, or in part; so we have no transition from one imagination to another, whereof we never had the like before in our senses.” Much of these rules, Hobbes says, do not really apply in our dreams.
The passage is obscure, but it indicates the principles known as contiguity, similarity, and contrast. Similar principles are stated by Zeno the Stoic, by Epicurus (see Diogenes Laertius vii. § 52, x. § 32), and by St Augustine of Hippo (Confessions, x. c. 19). Aristotle's doctrine was expanded and illustrated during throughout the Middle Ages, and in some cases even into the 17th century. William Hamilton listed philosophical authorities who gave prominence to the general fact of mental association - the Spanish philosopher Ludovicus Vives (1492–1540) especially being exhaustive in his account of memory.
In Thomas Hobbes's psychology much importance is assigned to what he called, variously, the succession, sequence, series, consequence, coherence, train of imaginations or thoughts in mental discourse. But not before David Hume is there an express question as to what are the distinct principles of association. John Locke had, meanwhile, introduced the phrase "association of ideas" as the title of a supplementary chapter incorporated with the fourth edition of his Essay, though with little or no suggestion of its general psychological import. Hume reduced the principles of association to three: similarity, contiguity in time and place, and cause and/or effect. Dugald Stewart suggested resemblance, contrariety, and vicinity in time and place, though he added, as another obvious principle, accidental coincidence in the sounds of words, and further noted three other cases of relation: cause and effect, means and end, and premise and conclusion, as connecting trains of thought under circumstances of special attention. Thomas Reid, made light of association, remarking that it seems to require only the power of habit to explain the spontaneous recurrence of trains of thinking, which become familiar by frequent repetition (Intellectual Powers, p. 387).