Unit VI: LearningModule 27

Operant Conditioning

Operant Conditioning 27-1

Operant Conditioning

• A type of learning in which a behavior is strengthened if followed by a reward or diminished if followed by a punisher.

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Skinner’s Experiments

B. F. Skinner’s experiments extend psychologist Edward Thorndike’s thinking, especially his law of

effect. This law states that rewarded behavior is likely to occur again.

Fish was the reward used to entice cats to find their way out of Thorndike’s puzzle box in 1898.

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Operant Chamber

Skinner developed the operant chamber which contains a bar or key that an animal manipulates to obtain food or water. The food or water is a reinforcer, an event that strengthens the

behavior it follows. The bar or key is connected to devices that record the animal’s response.

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Shaping

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 discriminateobjects of different shapes, colors and sizes.

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Types of Reinforcers 27-2

Types of Reinforcers

A heat lamp positively

reinforces a meerkat’s behavior

in the cold.

p. 278

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1. Primary Reinforcer: An innately reinforcing stimulus like food (when hungry) or drink (when thirsty).

2. Conditioned Reinforcer: A learned reinforcer that gets its reinforcing power through association with the primary reinforcer. Money is a conditioned reinforcer (desire for money is derived from the desire for food and other necessities).

Primary & Conditioned Reinforcers 27-2

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.

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Reinforcement Schedules 27-3

Reinforcement Schedules

1. Continuous Reinforcement: Reinforces the desired response each time it occurs (rarely occurs in real life).

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.

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Ratio Schedules

1. Fixed-ratio schedule: Reinforces a response only after a specified number of responses. e.g., a free drink after every 5 purchased at the local coffee shop.

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.)

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Interval Schedules

1. Fixed-interval schedule: Reinforces a response only after a specified time interval 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.)

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Schedules of Reinforcement

Figure 27.3,

page 280

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Punishment 27-4

Punishment

Punishment is an event that decreases the behavior it follows.

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Punishment

1. Punished behavior is suppressed, not forgotten – which may reinforce parents’ punishing behavior.

2. Punishment teaches discrimination among situations.

3. Punishment can teach fear.

4. Physical punishment may increase aggression by modeling aggression as a way to cope with problems.

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

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