Conditioning
Many animals use memory to learn. In order to learn, one must be able to remember past events and compare them to present situations. Even worms and snails can exhibit memory through their ability to be conditioned.
Classical Conditioning
In 1902, Ivan Pavlov, a
Russian scientist demonstrated a type of learning called classical
conditioning 
.
Classical Conditioning is a specific form of learning in which an otherwise
neutral stimulus (CS) is paired with a specific response (CR). This is taught
to the subject by paralleling the stimulus and response pair with an automatic
stimulus (US) and response (UR) pair which the subject already knows automatically.
Pavlov used dogs as his subjects. Each day, before feeding the dogs, he rang a bell. Before long, when the bell was rung, the dogs would begin to produce saliva before they were even exposed to the food. Normally, when a dog sees or smells food, it will automatically salivate because saliva aides in the digestive process. However, these dogs had learned to add a new saliva-producing cue - the bell. In the terms of a psychology experiment, the bell's ringing became a conditioned stimulus.
Classical Conditioning involves learning a response through physical repetition. There are four basic parts.
- Unconditioned Stimulus (US) - the natural cue that causes the animal to instinctively produce the UR.
- Unconditioned Response (UR) - instinctive behavior that results when the US is presented.
- Conditioned Stimulus (CS) - the unnatural cue that the subject will learn to respond to with the CR.
- Conditioned Response
(CR) - the response being learned that is initiated by the unnatural, learned
CS. The Conditioned Response can also be called the conditioned reflex.
It is usually
the same as the Unconditioned Response.
Operant Conditioning
In the early 1900's, American scientist Edward Lee Thorndike was working with cats. Instead of teaching his subjects to perform an instinctive behavior, he had them learn a completely new task. He put the cats inside "puzzle boxes." Through trial and error, the cats discovered they could get out by pulling on a string. Once they escaped, they were given food as a reward. He repeated the experiments with new boxes, and the cats learned how to open them more quickly by just pulling the string. (Yount, 1996, page 19) Thorndike called this instrumental learning.
B.F. Skinner's renamed this instrumental learning as operant conditioning. Skinner developed as special cage, now called a Skinner box, in which a rat must press a lever to get food. At first, the chance of the rat pressing the lever was random. With repeated occurrences of food being deposited after pressing the lever, the rat learns to associate its action with the reward. Skinner's favorite subjects were pigeons. ("B.F. Skinner", 1998) Skinner used these birds to develop the idea of shaping. To demonstrate this technique, he trained pigeons to turn around in circles. He rewarded the pigeons each time they turned just slightly to the left. Each time, more movement to the left is required to receive the reward. Before long, the pigeons were turning in circles.
