Unit 6 Learning Module 13 15 Unit 6 Learning Module 13 Classical Conditioning Pavlov Demonstrates Conditioning in Dogs In the early part of the 20th century Russian physiologist Ivan Pavlov 1849 1936 was studying the digestive system of dogs when he noticed that the dogs began to salivate when the lab technicians who normally fed them entered the room even though the dogs had not yet received any food Pavlov realized that the dogs were salivating because they new that they were about to be fed the dogs had begun to associate the arrival of the technicians with the food that soon followed their appearance in the room Pavlov began studying this process in more detail He conducted a series of experiments in which over a number of trials dogs were exposed to a sound immediately before receiving food He systematically controlled the onset of the sound and the timing of the delivery of the food and recorded the amount of the dogs salivation Initially the dogs salivated only when they saw or smelled the food but after several pairings of the sound and the food the dogs began to salivate as soon as they heard the sound The dogs learned to associate the sound with the food that Neutral stimulus a stimulus that produces no response Classical conditioning learning that occurs when a neutral stimulus tone becomes associated with a stimulus food that naturally produces a specific behavior After the association is learned the previously neutral stimulus is sufficient to produce the behavior Unconditioned stimulus US something food that triggers a natural occurring response Unconditioned response UR naturally occurring response salivation that follows the unconditioned stimulus Conditioned stimulus CS neutral stimulus that after being repeatedly presented prior to the unconditioned stimulus evokes a response similar to the unconditioned stimulus tone Conditioned response CR acquire response to the formerly neutral stimulus salivation In Pavlov s experiment the sound of the tone served as the conditioned stimulus that after learning produced the conditioned response The UR and the CR are the same behavior salivation but they are given different names because they are produced by different stimuli the US and the CS respectively Unit 6 Learning Module 13 15 Before conditioning the unconditioned stimulus US naturally produces the unconditioned response UR and the neutral stimulus whistle does not produce the salivation response The unconditioned stimulus US in this case the food is repeatedly presented immediately after the neutral stimulus After learning the neutral stimulus now known as the conditioned stimulus or CS is sufficient to produce the conditioned responses CR Conditioning is evolutionarily beneficial because it allows organisms to develop expectations that help them prepare for both good and bad events The conditioned stimulus and the unconditioned stimulus are repeatedly paired what happened when the conditioned response is presented alone The more that the CS and US are paired the stronger the CR in response to the CS The Persistence and Extinction of Conditioning Pavlov then studied the variables that influenced the strength and the persistence of conditioning In some studies after the conditioning had taken place Pavlov presented the sound repeatedly but without presenting the food afterward After the learning phase in which the conditioning occurred when the CS was then presented alone the behavior rapidly decreased the dogs salivated less and less to the sound and eventually the sound did not elicit salivation at all Extinction the reduction in responding that occurs when the conditioned stimulus is presented repeatedly without the unconditioned stimulus When a previously learned behavior disappears because the conditioned stimulus is no longer paired with the unconditioned stimulus At the end of the first extinction period the CS was no longer producing salivation the effects of conditioning had not entirely disappeared Pavlov found that after a pause sounding the tone again elicited salivation to a lesser extent than before extinction took place Spontaneous recovery The increase in responding to the CS following a pause after extinction A conditioned response has disappeared but it reappears the next when the conditioned stimulus is present Although the behavior has disappeared extinction is never complete If conditioning is again attempted the animal will learn the new associations much faster than it did the first time Pavlov also experimented with presenting new stimuli that were similar to the original conditioned stimulus If the dog had been conditioned to being scratched before the food arrived the stimulus would be changed to being rubbed rather than scratched He found that the dogs also salivated upon experiencing the similar stimulus a process known as generalization Generalization the tendency to respond to stimuli that resemble the original conditioned stimulus Responding to a new stimulus as if it were the original Discrimination the tendency to respond differently to stimuli that are similar but not identical Unit 6 Learning Module 13 15 Second order conditioning an existing conditioned stimulus can serve as an unconditioned stimulus for a pairing with a new conditioned stimulus If a dog salivates to meat and then learns to associate the mean with a light we have an example of first order conditioning You learn to blink when a bell sounds just before a puff of air blows in your eye and then later you learn to blink when a buzzer sounds just before the puff of air This is an example of first order conditioning When toby was young he got sick from spoiled shrimp so now he gets a sick feeling when he sees or smells shrimp When Toby s friends or family eat shrimp they dip it in cocktail sauce No toby gets a sick feeling when he sees or smells cocktail sauce This is an example of second order conditioning The Role of Nature in Classical Conditioning Scientists associated with the behaviorist school argued that all learning is driven by experience and not nature Classical conditioning which is based on learning through experience represents an example of the importance of the environment But classical conditioning cannot be understood entirely in terms of experience Nature also plays a part as our evolutionary history has made us better able to learn some associations than others Clinical psychologists make use of classical conditioning to explain the learning of a