Classic & Operant Conditioning | Chapter Five

Chapter 5 of PY201

Learning

• A relatively permanent change in behavior due to experience

• We learn by association - learning to associate one stimulus with another through repeated exposure to those stimuli

Classical Conditioning

• Learning by associating two stimuli and producing a learning (conditioned) response

• Observed in the study of Pavlov’s Dog

Ivan Pavlov and His Legacy

• Ivan Pavlov illustrated classical conditioning in a lab by training a dog to salivate in response to a bell

• Consider Pavlov’s experiment in two parts

  • Before Conditioning (phase 1)

  • After Conditioning (phase 2)

• Elements Present BEFORE Conditioning Can Occur

  • Unconditioned Stimulus (US)

    • a stimulus that elicits an unlearned response

  • Unconditioned Response (UR)

    • an unlearned, reflexive response

  • Neutral Stimulus (NS)

    • a stimulus that elicits no response at all

• Elements Evident AFTER Conditioning

  • **The neutral stimulus becomes a conditioned stimulus

  • Conditioned Stimulus (CS)

    • a previously neutral stimulus that comes to elicit a learned response after being paired with an unconditioned stimulus repeatedly

  • Conditioned Response (CR)

    • an acquired or learned response to a conditioned stimulus

Operant Conditioning

• Learning by associating behaviors with their resulting events (i.e. the consequences of behavior)

• The consequence of a behavior determines whether it’s likely to be repeated

• Two Kinds of Operant Conditioning

  • Reinforcement

    • a reinforcer is any consequence (stimulus) that strengthen a behavior

  • Punishment

    • A punisher is any consequence (stimulus) that weakens behavior

Thorndike’s Law of Effect

• The law states that rewarded behavior is likely to occur again

Positive vs. Negative Reinforcement

• Positive

  • Behavior is strengthened by the addition of a stimulus

  • Specifically, addition of something desirable or pleasant

  • You exercise more often (reinforced behavior) because you treat yourself to a smoothie afterwards (addition of a smoothie is desirable).

• Negative

  • Behavior is strengthened by the removal of a stimulus

  • Specifically, the removal of something aversive or unpleasant

  • You exercise more often (reinforced behavior) because you lose excess weight afterwards (the removal of excess weight—something undesirable)

Positive vs. Negative Punishment

• Positive

  • Behavior is weakened by the addition of a stimulus

  • Specifically, addition of something aversive or unpleasant

  • A child whispers more quietly (behavior weakened) because the teacher shhhes them (the addition of shhhh-ing is unpleasant and embarrassing)

• Negative

  • Behavior is weakened by the removal of a stimulus

  • Specifically, removal of something desirable or pleasant

  • You exercise less often (behavior weakened) because you missed time with your friends (the removal of fun times with friends weakened your exercise behavior)

Reinforcement Schedules and Their Ratios/Intervals

• Continuous Reinforcement Schedule

  • a system that reinforces a behavior every time it occurs

  • Results

    • Rapid Learning, rapid extinction

• Partial Reinforcement Schedule

  • a system that reinforces a response only part of the time

  • Results

    • Slower learning, but slower extinction

• Fixed Ratio Schedule

  • system that reinforces a behavior only after a specified number of responses

• Variable Ratio Schedule

  • system that reinforces behavior only after an unpredictable number of responses

• Fixed Interval Schedule

  • system that only reinforces a behavior after a specified time has elapsed

  • Results

    • Response pause after each reinforcer

• Variable Interval Schedule

  • system reinforces behavior at unpredictable time intervals

  • Results

    • Produces slow, steady responses