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Classical conditioning occurs when a conditioned stimulus (CS) is paired with an unconditioned stimulus (US). Usually, the conditioned stimulus is a neutral stimulus (e.g., the sound of a tuning fork), the unconditioned stimulus is biologically potent (e.g., the taste of food) and the unconditioned response (UR) to the unconditioned stimulus is an unlearned reflex response (e.g., salivation).
For example, a rat can be trained to push a lever to receive food whenever a light is turned on; in this example, the light is the antecedent stimulus, the lever pushing is the operant behavior, and the food is the reinforcer. Likewise, a student that receives attention and praise when answering a teacher's question will be more likely to ...
The conditioned emotional response is usually measured through its effect in suppressing an ongoing response. For example, a rat first learns to press a lever through operant conditioning. Classical conditioning follows: in a series of trials the rat is exposed to a CS, often a light or a noise. Each CS is followed by the US, an electric shock.
Shaping sometimes fails. An oft-cited example is an attempt by Marian and Keller Breland (students of B.F. Skinner) to shape a pig and a raccoon to deposit a coin in a piggy bank, using food as the reinforcer. Instead of learning to deposit the coin, the pig began to root it into the ground, and the raccoon "washed" and rubbed the coins together.
In Pavlov's original demonstration of classical conditioning, he used a backward conditioning arrangement as the control condition. Briefly, in that procedure, the dogs experienced the same number of US presentations (food) and the same number of CS presentations (metronome ticking) as the experimental groups, but the timing of the CS and US ...
Van Hamme and Wasserman have extended the original Rescorla–Wagner (RW) model and introduced a new factor in their revised RW model in 1994: [3] They suggested that not only conditioned stimuli physically present on a given trial can undergo changes in their associative strength, the associative value of a CS can also be altered by a within-compound-association with a CS present on that trial.
Then, there are more conditioning trials, this time with the light (CS1) and a tone (CS2) together with the US. Now, when tested, the agent does not salivate to the tone (CS2). In other words, an association between the tone CS2 and the US has been "blocked" because the CS1–US association already exists.
Pavlovian-instrumental transfer (PIT) is a psychological phenomenon that occurs when a conditioned stimulus (CS, also known as a "cue") that has been associated with rewarding or aversive stimuli via classical conditioning alters motivational salience and operant behavior.