This is the 2007 version. Click here for the 2017 chapter 05 table of contents.

Conditional Response

Now we come to the labels for elements of a classical conditioning experiment. These are the terms which students apparently find difficult to remember. The best way to learn them is to notice what they mean. For example, think of conditional as meaning conditional upon learning or dependent upon conditions.

Pavlov labeled the signal that occurs before a biologically significant event a conditional stimulus (CS). Its ability to trigger salivation is conditional, that is, "depending on conditions." It does not automatically trigger salivation in an untrained dog. Another way to remember what CS stands for is to think of the word CUES. The conditional stimulus is what cues the conditional response. Pavlov sounded a tone (the CS) before giving the dog meat powder.

What do the abbreviations CS and CR stand for? Why is the word "unconditional" used?

How did Pavlov initiate the biological reflex of salivation? He squirted meat powder in the dog's mouth. Even before learning, salivation is triggered by meat powder. So this response is said to be unconditional (not dependent upon special learning conditions). The meat powder is called the unconditional stimulus (US) It is the stimulus that provokes a response automatically. Because the salivation response to meat powder is born-in and unconditional, it is called the unconditional response (UR) Every reflex such as those listed earlier consists of an unconditional stimulus that triggers an unconditional response.

To repeat: classical conditioning occurs when a signal (CS) is put before the reflex (or paired with it as many textbooks say, although conditioning is faster if the CS comes before the reflex). For example, the tone is sounded before the meat powder is squirted into the dog's mouth. Then the dog anticipates the meat powder when it hears the tone. Therefore it salivates to the tone. The salivation that occurs in response to the tone is the conditional response (CR). It depends on a prior act of learning, hence the name "conditional." After training, the CR occurs in response to the CS (conditional stimulus).

How is the CR different from the UCR?

The unconditional response and conditional response obviously resemble each other, but they are not identical. They have different causes (one is a reaction to the biologically natural stimulus; the other is a learned reaction to a signal). They also occur at a different strength. The conditional response is typically somewhat weaker than the natural response to an unconditional stimulus. A dog does not salivate as much to the signal as it does to real food. Watson's subjects probably did not withdraw their fingertips quite as vigorously when they heard a bell as when they actually received a shock. So the two have different names. The original, reflex response is the unconditional response. The learned response is the conditional response.

Due to a mistranslation of Pavlov's early works, most psychologists refer to "conditioned responses" rather than "conditional responses." Conditional is actually the correct translation of the Russian word, which is uslovnye (Fitzpatrick, 1990).

What mistranslation of Pavlov's terms occurred? Why is "conditional" arguably more meaningful than "conditioned"?

The word conditional is arguably more meaningful than conditioned. In the classic Pavlovian setup, the dog salivates because of previous experience. Therefore the CR is literally conditional upon the association of the CS with the reflex. The word conditioned carries no such meaning, unless one make a comparison between the establishment of a conditional response and the conditioning of a piece of metal by pounding it into shape-a metaphor Pavlov did not intend. Cyril Franks, a noted behavior therapist, wrote the following in an essay titled "Behavior Therapy and Its Pavlovian Origins."

What did Cyril Franks say about Pavlov's view of CRs?

Pavlov distrusted absolutism in any form, and it was no accident that he employed the term "conditional" in his writings rather than "conditioned." His intent was to convey the essentially temporary nature of the connections thus formed, connections that lacked the certainty and regularity of innate or "unconditional" reflexes. For Pavlov...the conditional reflex was a creative, emergent activity of the organism, not a stereotyped or unchanging process. (Franks, 1973)

What happened to Pavlov's theory after the communist revolution in 1917?

Franks may have written "Pavlov distrusted absolutism in any form" to counteract a widespread belief that Pavlov sold out to the communist regime after the Bolshevik revolution in 1917. Lenin, leader of the Russian revolution, had the highest respect for Pavlov, one of his country's greatest scientists. Lenin's endorsement made Pavlovian psychology the state-approved psychology of the Soviet Union. To this day, some Russian psychologists believe classical conditioning can explain a large percentage of human behavior. To be fair, some American psychologists feel the same way about operant conditioning.


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