Famous Psychology Experiments 1 B F Skinner and
Famous Psychology Experiments 1
B. F. Skinner and Operant Conditioning • Classical conditioning involves an automatic response to a stimulus (learner plays a passive role) Pavlov & Watson • Operant conditioning involves learning how to control one’s response to elicit a reward or avoid a punishment (learner plays an active role) (BF Skinner) 2
Edward L. Thorndike • Animals placed in puzzle boxes • String pulled, latch released, animal jumps out and receives food • Learning by random trial and error • Law of Effect – Thorndike’s principle that responses are “stamped in” by rewards and “stamped out” by punishments.
Elements of Operant Conditioning • Reinforcer – A stimulus or event that follows a behavior and makes that behavior more likely to occur again • Punisher – A stimulus or event that follows a behavior and makes that behavior less likely to occur again
Skinner’s Experiments Skinner’s experiments extend Thorndike’s thinking, especially his law of effect. This law states that rewarded behavior is likely to occur again. Yale University Library
Operant Chamber Using Thorndike's law of effect as a starting point, Skinner developed the Operant chamber, or the Skinner box, to study operant conditioning. Walter Dawn/ Photo Researchers, Inc.
The “Skinner Box”: Skinner’s Hypothesis, Methodology, and Results • Rats placed in “Skinner boxes” • Shaping-guiding behavior (successive approximations) • Shape rats closer and closer to the bar to receive food. • Food is a reinforcer 7
Shaping is the operant conditioning procedure in which reinforcers guide behavior towards the desired target behavior through successive approximations. A rat shaped to sniff mines. A manatee shaped to discriminate objects of different shapes, colors and sizes.
Basic Types of Reinforcement Reinforcer: any event that increases or strengthens a behavior it follows. Primary Reinforcer: innately satisfying (not learned, i. e. food) Secondary Reinforcer: power through association with primary reinforcers (learned, i. e. good grades) Positive Reinforcement: strengthens a response by presenting a desirable stimulus after a response (Praise, money) 11
Law of Effect-Thorndike • Reinforced behaviors are strengthened • Punished behaviors are decreased 12
What is Negative Reinforcement? • Write down a word or phrase that means the same thing as Negative Reinforcement. 13
Types of Reinforcement • Positive reinforcer (+) – Adds something rewarding following a behavior, making that behavior more likely to occur again – Giving a dog a treat for fetching a ball is an example • Negative reinforcer (-) – Removes something unpleasant that was already in the environment following a behavior, making that behavior more likely to occur again – Taking an aspirin to relieve a headache is an example
Immediate & Delayed Reinforcers 1. Immediate Reinforcer: A reinforcer that occurs instantly after a behavior. A rat gets a food pellet for a bar press. 2. Delayed Reinforcer: A reinforcer that is delayed in time for a certain behavior. A paycheck that comes at the end of a week. We may be inclined to engage in small immediate reinforcers (watching TV) rather than large delayed reinforcers (getting an A in a course) which require consistent study.
Negative Reinforcement and Punishment Negative reinforcement: Removing an unpleasant stimulus 1. Unpleasant stimulus Punishment 1. Introducing an unpleasant stimulus = 2. Removal of unpleasant stimulus = 2. Withholding a pleasant stimulus 18
Punishment An aversive event that decreases the behavior it follows.
Punishment • Goal of punishment is to decrease the occurrence of a behavior • Effective punishment – Should occur as soon as possible after the behavior – Should be sufficient, i. e. , strong enough – Should be certain, occurring every time the behavior does – Should be consistent
Punishment Although there may be some justification for occasional punishment (Larzelaere & Baumrind, 2002), it usually leads to negative effects. 1. Results in unwanted fears. 2. Conveys no information to the organism. 3. Justifies pain to others. 4. Causes unwanted behaviors to reappear in its absence. 5. Causes aggression towards the agent. 6. Causes one unwanted behavior to appear in place of another.
Big Bang Theory • Operant Conditioning • Video Clip • What kind of reinforcement was used? • Negative Reinforcement vs. Punishment video clip 23
Rates and Types of Reinforcement: Additional Experiments Fixed-ratio: after a fixed number of responses reinforcement is given. (sales) Produces high response rate Variable-ratio: after an unpredictable number of responses reinforcement is given (gambling) Produces high response rate Fixed-interval: after a fixed amount of time reinforcement is given. (mail) Variable-interval: after an unpredictable amount of time reinforcement is given (email) 24
Skinner’s Importance Education: programmed instruction Parenting Work Personal goals 25
Learned Helplessness • Failure to try to avoid an unpleasant stimulus because in the past it was unavoidable • Possible model for depression in humans
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