Classical conditioning (also known as Pavlovian Association) is one of the most basic forms of associative learning that was first demonstrated by Ivan Pavlov and his dogs in 1927.
This Scientific America piece takes a closer look:
Classical Conditioning, Explained
The most important thing to remember is that classical conditioning involves automatic or reflexive responses, and not voluntary behavior (that’s operant conditioning, and that is a different post). What does this mean? For one thing, that means that the only responses that can be elicited out of a classical conditioning paradigm are ones that rely on responses that are naturally made by the animal (or human) that is being trained. Also, it means that the response you hope to elicit must occur below the level of conscious awareness – for example, salivation, nausea, increased or decreased heartrate, pupil dilation or constriction, or even a reflexive motor response (such as recoiling from a painful stimulus). In other words, these sorts of responses are involuntary.
I remember something about Pavlov's Dogs
Before learning took place, the dogs would reliably salivate (UCR) when given meat powder (UCS), but they gave no response to the ringing of a bell (neutral). Then Pavlov would always ring a bell just before he would present the dogs with some meat powder. Pretty soon, the dogs began to associate the sound of the bell with the impending presence of meat powder. As a result, they would begin to salivate (CR) as soon as they heard the bell (CS), even if it was not immediately followed by the meat powder (UCS). In other words, they learned that the bell was a reliable predictor of meat powder. In this way, Pavlov was able to elicit an involuntary, automatic, reflexive response to a previously neutral stimulus.
This reminds me of Charlie Munger's application of these principles in business life. In an essay entitled “Turning $2 Million Into $2 Trillion,” Munger offers the following insight:
…Let us start by exploring the consequences of our simplifying “no-brainer” decision that we must rely on a strong trademark. This conclusion automatically leads to an understanding of the essence of our business in proper elementary academic terms. We can see from the introductory course in psychology that, in essence, we are going into the business of creating and maintaining conditioned reflexes. The “Coca-Cola” trade name and trade dress will act as the stimuli, and the purchase and ingestion of our beverage will be the desired responses.
And how does one create and maintain conditioned reflexes? Well, the psychology text gives two answers: by operant conditioning, and (2) by classical conditioning, often called Pavlovian conditioning to honor the great Russian scientist. And, since we want a lollapalooza result, we must use both conditioning techniques – and all we can invent to enhance effects from each technique.
The operant-conditioning part of our problem is easy to solve. We need only (1) maximize rewards of our beverage’s ingestion, and (2) minimize possibilities that desired reflexes, once created by us, will be extinguished through operant conditioning by proprietors of competing products.
For operant conditioning rewards, there are only a few categories we will find practical:
(1) Food value in calories or other inputs;
(2) Flavor, texture, and aroma acting as stimuli to consumption under neural preprogramming of a man through Darwinian natural selection;
(3) Stimulus, as by sugar or caffeine;
(4) Cooling effect when man is too hot or warming effect when man is too cool.
Read this for more on the difference between classical and operant conditioning.
Wikipedia mentions two references in novels as well:
One of the earliest literary references to classical conditioning can be found in the comic novel The Life and Opinions of Tristram Shandy, Gentleman (1759) by Laurence Sterne. The narrator Tristram Shandy explains how his mother was conditioned by his father's habit of winding up a clock before having sex with his wife:
My father […] was, I believe, one of the most regular men in every thing he did […] [H]e had made it a rule for many years of his life,—on the first Sunday-night of every month throughout the whole year,—as certain as ever the Sunday-night came,—to wind up a large house-clock, which we had standing on the back-stairs head, with his own hands:—And being somewhere between fifty and sixty years of age at the time I have been speaking of,—he had likewise gradually brought some other little family concernments to the same period, in order, as he would often say to my uncle Toby, to get them all out of the way at one time, and be no more plagued and pestered with them the rest of the month. […] [F]rom an unhappy association of ideas, which have no connection in nature, it so fell out at length, that my poor mother could never hear the said clock wound up,—but the thoughts of some other things unavoidably popped into her head—& vice versa:—Which strange combination of ideas, the sagacious Locke, who certainly understood the nature of these things better than most men, affirms to have produced more wry actions than all other sources of prejudice whatsoever.
Another example is in the dystopian novel, A Clockwork Orange in which the novel's anti-hero and protagonist, Alex, is given a solution to cause severe nausea, and is forced to watch violent acts. This renders him unable to perform any violent acts without inducing similar nausea.