Backward Conditioning in Classical Conditioning

What is backward conditioning

Backward conditioning is a behavior conditioning method that presents the stimuli in a reverse order, that is, the unconditioned stimulus (US) occurs before the neutral stimulus (NS).

The results of backward conditioning is the topic of debate in the psychology field. While some scientists found no associated learning was formed, others found that the neutral stimulus had become a conditioned inhibitor^​1​.

Backward conditioning as extinction

Neutral stimulus following the unconditioned stimulus is not conditioned like the forward Pavlovian conditioning. Instead, it contributes to conditioned inhibition and can be used as an extinction agent.

For example, a rat is forward conditioned to associate noise (CS) with shock (US) to cause fear (CR) while they lick a water tube. So, after the excitatory conditioning procedure, noise alone can induce fear and lick suppression in the rat.

In regular classical conditioning extinction, CS will be given alone without being followed by US. If extinction is successful, CS will gradually lose its power to trigger fear in the rat. However, if backward conditioning is used instead, i.e. US is presented before CS, the extinction happens immediately^​2​.

Therefore, once an excitatory conditioned response (CR) has been established, it can be weakened by the backward method of conditioning.

However, under some circumstances, the backward conditioning treatments can have different conditioning effects. Instead of being an inhibitor, the backward-conditioned stimulus becomes a conditioned excitor^​3​.

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