Chapter 6: Learning/Conditioning

CLASSICAL CONDITIONING A simple form of learning in which one stimulus calls forth the response that is usually called forth by another stimulus. This occurs when the two stimuli have been associated with each other. I know….sounds kind of confusing but let me explain! Learning through association Your environment causes you to act a certain way Ivan Pavlov 1849-1936

The Famous Experiment Pavlov was studying the role of saliva in the digestive processes of dogs. The dogs were restrained by a harness and their saliva was collected by a surgically implanted tube in the salivary gland. Pavlov would present meat powder to the dogs and then collect the resulting saliva. As his research progressed he noticed that dogs accustomed to the procedure would start salivating before the meat powder was presented. For instance, they would salivate in response to a clicking sound made by the device that was used to present the meat powder. Intrigued by this unexpected finding, Pavlov decided to investigate further. He paired the presentation of meat powder with various stimuli. In some experiments, he used a simple auditory stimulus- the presentation of a tone (bell). After the tone and meat powder were paired together a number of times, the tone was presented alone. What happened? The dogs responded by salivating to the sound of the tone alone. The tone was a neutral stimulus until it was paired with the meat powder.

Learning through association Your environment causes you to act a certain way

Important Terminology and Procedures Unconditioned Stimulus (US)- a stimulus that evokes an unconditioned response without previous conditioning Unconditioned Response(UR)- an unlearned reaction to an unconditioned stimulus that occurs with out previous conditioning. The bond between the meat powder and salivation was a natural, unlearned association. It did not have to be created through conditioning.

In contrast, the link between the tone (bell) and salivation was established through conditioning.. Conditioned Stimulus (CS)- a previously neutral stimulus that has, through conditioning, acquired the capacity to evoke a conditioned response. Conditioned Response (CR)- a learned reaction to a conditioned stimulus that occurs because of previous conditioning In Pavlov’s experiment the CR and the UR were the same! Although the UR and the CR sometimes consist of the same behavior there usually are subtle differences. CR often are weaker and less intense.

Sometimes the CR and the UR are different. EX- If an animal is given a brief shock as a US and the UR is pain, the CR is fear.

Real Life! If you cringe when you hear the sound of a dentist’s drill, this response is a result of classical conditioning. In this case, pain has been paired with the sound of the drill, which became the CS eliciting your cringe.

Evaluative Conditioning- changes in the liking of a stimulus that result from pairing that stimulus with other positive or negative stimuli

Acquisition- initial stage of learning something. Extinction- the gradual weakening and disappearance of a conditioned response Spontaneous Recovery- the reappearance of an extinguished response after a period of no exposure to the conditioned stimulus. Renewal effect- if a response is extinguished in a different environment than where it was acquired, the extinguished response will reappear if the animal is returned to the original environment where acquisition took place.

Generalization- occurs when an organism that has learned a response to a specific stimulus responds in the same way to a new stimuli that are similar to the original stimulus. Little Albert Experiment. Discrimination- occurs when an organism that has learned a response to a specific stimulus does not respond in the same way to new stimuli that are similar to the original stimulus.

OPERANT CONDITIONING A form of learning in which responses come to be controlled by their consequences.

B.F. Skinner Skinner demonstrated that organisms tend to repeat those responses that are followed by favorable consequences. Reinforcement -a response is strengthened because it leads to rewarding consequences.

Can you give me an example of a time when you were reinforced? You put money in a pop machine……you get pop You go to work……….you get a paycheck. You tell a joke……your friends laugh IMPORTANT: Something that is clearly reinforcing an organism at one time may not function as a reinforcer later. For example, food may not be reinforcing if an organism is not hungry. Also…something that is a reinforcer for one person may not be for someone else. For example, parental approval is a potent reinforcer for most children but not all.

Terms to remember Operant chamber or Skinner box: a small enclosure in which an animal can make a specific response that is recorded while the consequences of the response are systematically controlled. Reinforcement Contingencies- the experimenter sets the rules. Ex- the rat pushes a lever then the rat gets food Primary Reinforcers- reinforcers that satisfy basic biological needs. Ex- food, water, warmth Secondary Reinforcers- reinforcers that we learn to like. Money, good grades, applause.

Basic Processes in Operant Conditioning Shaping- Repeatedly reinforcing closer and closer approximations of a desired response until the desired response is achieved.

Extinction- the gradual weakening and disappearance of a response tendency because the response is no longer followed by reinforcers. Resistance to extinction- occurs when an organism continues to make a response after delivery of the reinforcer has been terminated. Discriminative stimuli- cues that influence operant behavior by indicating the probable consequences of a response. Ex- Birds know they will find more warms after rain.

SCHEDULES OF REINFORCEMENT How often are you reinforced? Continuous Reinforcement- occurs when every instance of a designated response is reinforced. Intermittent or Partial Reinforcement- occurs when a designated response is reinforced only some of the time. Which do you suppose leads to a longer-lasting effects?

Fixed Ratio Fixed Interval Variable Ratio Variable Interval The reinforcer is given a fixed number of non-reinforced responses. Ex- A rat is reinforced after every tenth lever push Fixed Interval The reinforcer is given for the first response that occurs after a fixed time interval has elapsed. Ex- Every two minutes the rat is reinforced Variable Ratio The reinforcer is given after a varied number of non-reinforced responses. Ex- A rat is reinforced after the tenth lever push then after the fifth then the third and so on. Variable Interval The reinforcer is given for the first response after a varied time interval has elapsed. Ex- A rat is reinforced for the first lever push after one minute then after ten minutes…….etc…it is always changing

Positive Reinforcement Versus Negative Reinforcement Positive Reinforcement- occurs when a response is strengthened because it is followed by the presentation of a rewarding stimulus. Ex- good grades, tasty meals, paychecks, promotions, scholarships etc.. Negative Reinforcement- occurs when a response is strengthened because it is followed by the removal of an unpleasant stimulus. Don’t let the word negative confuse you. Negative reinforcement is reinforcement. Like all reinforcement it involves a favorable outcome that strengthens a response tendency. However, this strengthening takes place because a response leads to the removal of an unpleasant stimulus rather than the arrival of a pleasant stimulus.

EXAMPLES While a rat is in a Skinner box, a moderate electric shock is delivered to the animal through the floor of the box. When the rat presses the lever, the shock is turned off for a period of time. Thus, lever pressing leads to the removal of the shock (unpleasant stimuli). You rush home to get out of the cold. You clean your house to get rid of the mess

Escape Learning- an organism acquires a response that decreases or ends some annoying stimulation Avoidance Learning- an organism acquires a response that prevents some unpleasant stimulation from occurring.

Punishment Occurs when an event following a response weakens the tendency to make that response. Ex- In a Skinner box, the use of punishment is very simple. When a rat presses a lever , it receives a shock. This usually leads to a decrease in lever pushing. NEGATIVE REINFORCEMENT STRENGTHENS A RESPONSE, WHEREAS PUNISHMENT WEAKENS A RESPONSE.

OBSERVATIONAL LEARNING Occurs when an organism’s responding is influenced by the observation of others who are called models. Example: You see a friend behaving assertively with a car salesperson. You see your friend’s assertive behavior gets reinforced by a exceptionally good buy and she gets the car. You are not reinforced but you are observing reinforcement.