Conditioning

Conditioning is a training technique that takes one of two forms: Classical/Pavlovian conditioning or Operant/Instrumental conditioning.

Classical Conditioning

Classical conditioning (also Pavlovian conditioning or respondent conditioning) is a kind of learning that occurs when a conditioned stimulus (CS) is paired with an unconditioned stimulus (US). Usually, the CS is a neutral stimulus (e.g., the sound of a tuning fork), the US is biologically potent (e.g., the taste of food) and the unconditioned response (UR) to the US is an unlearned reflex response (e.g., salivation). After pairing is repeated (some learning may occur already after only one pairing), the organism exhibits a conditioned response (CR) to the CS when the CS is presented alone. The CR is usually similar to the UR (see below), but unlike the UR, it must be acquired through experience and is relatively impermanent.

Classical conditioning differs from operant or instrumental conditioning, in which a behavior is strengthened or weakened, depending on its consequences (i.e., reward or punishment). A classic experiment by Pavlov exemplifies the standard procedure used in classical conditioning. First Pavlov observed the UR (salivation) produced when meat powder (US) was placed in the dog's mouth. He then rang a bell (CS) before giving the meat powder. After some repetitions of this pairing of bell and meat the dog salivated to the bell alone, demonstrating what Pavlov called a "conditional" response, now commonly termed "conditioned response" or CR.

It is often thought that the conditioned response is a replica of the unconditioned response, but Pavlov noted that saliva produced by the CS differs in composition from what is produced by the US. In fact, the CR may be any new response to the previously neutral CS that can be clearly linked to experience with the conditional relationship of CS and US. It was also thought that repeated pairings are necessary for conditioning to emerge, however many CRs can be learned with a single trial as in fear conditioning and taste aversion learning.

Forward Conditioning

Learning is fastest in forward conditioning. During forward conditioning, the onset of the CS precedes the onset of the US in order to signal that the US will follow. Two common forms of forward conditioning are delay and trace conditioning.

• Delay conditioning: In delay conditioning the CS is presented and is overlapped by the presentation of the US. The difference between trace conditioning and delay conditioning is that in the delayed procedure the CS and US overlap.

• Trace conditioning: During trace conditioning the CS and US do not overlap. Instead, the CS begins and ends before the US is presented. The stimulus-free period is called the trace interval. It may also be called the conditioning interval. For example: If you sound a buzzer for 5 seconds and then, a second later, puff air into a person’s eye, the person will blink. After several pairings of the buzzer and puff the person will blink at the sound of the buzzer alone.

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Classical Conditioning

Simultaneous conditioning

Classical conditioning procedures and effects During simultaneous conditioning, the CS and US are presented and terminated at the same time. For example: If you ring a bell and blow a puff of air into a person’s eye at the same moment, you have accomplished to coincide the CS and US.

Second-order and higher-order conditioning

This form of conditioning follows a two-step procedure. First a neutral stimulus (“CS1”) comes to signal a US through forward conditioning. Then a second neutral stimulus (“CS2”) is paired with the first (CS1) and comes to yield its own conditioned response. For example: a bell might be paired with food until the bell elicits salivation. If a light is then paired with the bell, then the light may come to elicit salivation as well. The bell is the CS1 and the food is the US. The light becomes the CS2 once it is paired with the CS1

Backward conditioning

Backward conditioning occurs when a CS immediately follows a US. Unlike the usual conditioning procedure, in which the CS precedes the US, the conditioned response given to the CS tends to be inhibitory. This presumably happens because the CS serves as a signal that the US has ended, rather than as a signal that the US is about to appear. For example, a puff of air directed at a person's eye could be followed by the sound of a buzzer.

Temporal conditioning

Temporal conditioning is when a US is presented at regular intervals, for instance every 10 minutes. Conditioning is said to have occurred when the CR tends to occur shortly before each US. This suggests that animals have a biological clock that can serve as a CS. This method has also been used to study timing ability in animals. (see Animal cognition).

Zero contingency procedure

In this procedure, the CS is paired with the US, but the US also occurs at other times. If this occurs, it is predicted that the US is likely to happen in the absence of the CS. In other words, the CS does not "predict" the US. In this case, conditioning fails and the CS does not come to elicit a CR. This finding - that prediction rather than CS-US pairing is the key to conditioning - greatly influenced subsequent conditioning research and theory.

Extinction

In the extinction procedure, the CS is presented repeatedly in the absence of a US. This is done after a CS has been conditioned by one of the methods above. When this is done the CR frequency eventually returns to pre-training levels. However, spontaneous recovery (and other related phenomena, see "Recovery from extinction" below) show that extinction does not completely eliminate the effects of the prior conditioning. Spontaneous recovery is when there is a sudden appearance of the (CR) after extinction occurs.

Instrumental Conditioning

Operant conditioning (or instrumental conditioning) is a type of learning in which an individual's behavior is modified by its antecedents and consequences. Instrumental conditioning was first discovered and published by Jerzy Konorski and was also referred to as Type II reflexes. Mechanisms of instrumental conditioning suggest that the behavior may change in form, frequency, or strength. The expressions "operant behavior" and "respondent behavior" were popularized by B. F. Skinner who worked on reproduction of Konorski's experiments. The former refers to "an item of behavior that is initially spontaneous, rather than a response to a prior stimulus, but whose consequences may reinforce or inhibit recurrence of that behavior".

Operant conditioning is distinguished from classical conditioning (or respondent conditioning) in that operant conditioning deals with the reinforcement and punishment to change behavior. Operant behavior operates on the environment and is maintained by conditioning of reflexive (reflex) behaviors which are also elicited by antecedent conditions, while classical conditioning is maintained by its antecedents and consequences. Behaviors conditioned through a classical conditioning procedure are not maintained by consequences. They both, however, form the core of behavior analysis and have grown into professional practices.