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Learning II:Skinnerian

Brian J. Piper, Ph.D.

Operant Conditioning Skinner’s Experiments Extending Skinner’s

Understanding Skinner’s Legacy Contrasting Classical & Operant

Conditioning

Burrhus Frederic Skinner1904-1990

Operant & Classical Conditioning

1. Classical conditioning forms associations between stimuli (CS and US). Operant conditioning, on the other hand, forms an association between behaviors and the resulting events.

Operant & Classical Conditioning

2. Classical conditioning involves respondent behavior that occurs as an automatic response to a certain stimulus. Operant conditioning involves operant behavior, a behavior that operates on the environment, producing rewarding or punishing stimuli.

Thorndike’s Experiments

Edward Thorndike discovered the law of effect. This law states that rewarded

behavior is likely to occur again.

Yale U

niversity Library

1874-1949

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.

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Operant Chamber

The operant chamber, or Skinner box, comes with a bar or key that an

animal manipulates to obtain a

reinforcer like food or water. The bar or key is connected to devices that record

the animal’s response.

Shaping Lever Pressing Behavior

• simply turning toward the lever will be reinforced• only stepping toward the lever will be reinforced• only moving to within a specified distance from the lever will

be reinforced• only touching the lever with any part of the body, such as the

nose, will be reinforced• only touching the lever with a specified paw will be reinforced• only depressing the lever partially with the specified paw will

be reinforced• only depressing the lever completely with the specified paw

will be reinforced

ShapingShaping is the operant conditioning procedure in which reinforcers guide behavior towards the desired target behavior through successive approximations.

10 min:http://www.youtube.com/watch?v=NhmZBMuZ6vE

Types of Reinforcers

Reinforcement: Any event that strengthens the behavior it follows.

1. Primary Reinforcer: An innately reinforcing stimulus like food or drink.

2. Secondary Reinforcer: A learned reinforcer that gets its reinforcing power through association with the primary reinforcer.

Primary & Secondary 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.

Immediate & Delayed Reinforcers

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.

Reinforcement Schedules

1. Continuous Reinforcement: Reinforces the desired response each time it occurs.

2. Partial Reinforcement: Reinforces a response only part of the time. Though this results in slower acquisition in the beginning, it shows greater resistance to extinction later on.

Ratio Schedules

1. Fixed-ratio schedule: Reinforces a response only after a specified number of responses. e.g., piecework pay.

2. Variable-ratio schedule: Reinforces a response after an unpredictable number of responses. This is hard to extinguish because of the unpredictability (e.g., behaviors like gambling, fishing).

Interval Schedules

1. Fixed-interval schedule: Reinforces a response only after a specified time has elapsed. (e.g., preparing for an exam only when the exam draws close.)

2. Variable-interval schedule: Reinforces a response at unpredictable time intervals, which produces slow, steady responses. (e.g., pop quiz.)

Applications of Operant Conditioning

Skinner introduced the concept of teaching machines that shape learning in small steps and provide immediate reinforcements for correct responses. They also provide individualized

instruction.

In School

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Skinner (1958). Science, 128, 969-977.

Applications of Operant Conditioning

• Animal training• Applied Behavior Analysis:

– Worth video Sampler: 2004 Abnormal Psychology

Punishment

Any event that decreases the behavior it follows.

Punishment

1. Results in unwanted fears.2. Conveys no information to the organism.3. Causes unwanted behaviors to reappear

in its absence4. Justifies pain to others.5. Causes aggression towards the agent.

Although there may be some justification for occasional punishment, it usually leads to negative effects.

Biological Predisposition

Biological constraints predispose

organisms to learn associations that are naturally adaptive.

Breland and Breland (1961) showed that

animals drift towards their biologically

predisposed instinctive behaviors. Marian Breland Bailey

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Latent Learning

Tolman & Honzik (1930) University of California Publications in Psychology, 4, 257-275.

Latent Learning

Tolman & Honzik (1930) University of California Publications in Psychology, 4, 257-275.

Skinner’s Legacy

Skinner argued that behaviors were shaped by external influences instead of

inner thoughts and feelings.

Most “Eminent” Psychologist of 20th Century

• Eminence was defined based on:– journal citation frequency– textbook citation frequency – survey of professional society (APS)– Membership in National Academy of Sciences

Haggbloom et al. (2002). Review of General Psychology, 6, 139-159.

Most “Eminent” Psychologists of 20th Century

History of BehaviorismKey Quote (1930)

“Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select – doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors. I am going beyond my facts and I admit it, but so have the advocates of the contrary and they have been doing it for many thousands of years.”

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Originator Ivan Pavlov Fred Skinner