PBSI 107 Lecture Notes

PBSI 107 Notes

SHAPING

• Definition: Shaping is a tool used in operant conditioning to reward successive approximations of a target behavior.

  • This method involves breaking down behaviors into many small, achievable steps.

  • It is particularly useful when teaching a complex chain of events.

  • Commonly utilized by animal trainers, including with pigeons.

Steps of Shaping

1. Reinforce Initial Responses: Reinforce any response that resembles the desired behavior.

2. Narrowing Reinforcement: Then, reinforce the response that more closely resembles the desired behavior; no longer reinforce previously reinforced responses.

3. Progressive Refinement: Continue this process until only the final desired behavior is reinforced.

4. Further Closening: Begin to reinforce the response that even more closely resembles the desired behavior.

PRIMARY & SECONDARY REINFORCERS

• Primary Reinforcers:

  • Have innate reinforcing qualities.

  • The reinforcement value is unlearned.

  • Examples: Food, water, sex, sleep, etc.

• Secondary Reinforcers:

  • Do not have inherent reinforcing value.

  • The reinforcement value is learned and paired with a primary reinforcer.

  • Examples: Money, which is often associated with food and other primary needs.

  • Token Economies:

  • Used in various settings, such as schools and prisons, to encourage desired behaviors.

REINFORCEMENT SCHEDULES

• The most effective method for teaching a behavior is through positive reinforcement.

• There are multiple ways in which positive reinforcement can be administered.

Continuous Reinforcement

• Definition: An organism receives a reinforcer each time it displays a behavior.

  • Characteristics:

  • This is the quickest way to teach a behavior.

  • Example: A dog receives a treat each time it sits when told to.

  • Timing Importance: Timing is crucial; the reinforcer (treat) must be presented immediately after the behavior (sitting) for effective association.

• Limitation:

  • If reinforcement stops, the learned behavior may cease (e.g., a dog may stop sitting on command).

Partial Reinforcement

• Definition: Refers to when an organism is not reinforced every time they display the desired behavior, but rather they are reinforced intermittently.

• Several types of partial reinforcement schedules exist.

PARTIAL REINFORCEMENT SCALES

Two Key Factors

1. Consistency:

   • Fixed: A consistent and unchanging amount of either the number of responses or the amount of time between reinforcements.

   • Variable: An inconsistent amount of either the number of responses or the amount of time between reinforcements.

2. Based on What:

   • Interval: The schedule is based on the time between reinforcements.

   • Ratio: The schedule is based on the number of responses between reinforcements.

Types of Partial Reinforcement Schedules

• Fixed Interval: Reinforcement is delivered at predictable time intervals.

  • Example: Patients taking pain relief medication at set times.

• Variable Interval: Reinforcement is delivered at unpredictable time intervals.

  • Example: Checking social media for notifications.

• Fixed Ratio: Reinforcement is delivered after a predictable number of responses.

  • Example: Factory workers being paid for every X number of items manufactured.

• Variable Ratio: Reinforcement is delivered after an unpredictable number of responses.

  • Example: Gambling.

RESPONSES PATTERNS IN REINFORCEMENT SCHEDULES

• The four reinforcement schedules yield different response patterns.

  • Cumulative Number of Responses:

  • Variable Ratio: High and steady response rates, little pause.

  • Fixed Ratio: High response rate with short pause.

  • Interval Patterns:

  • Variable Interval: Moderate, steady response rate.

  • Fixed Interval: Scallop-shaped response pattern reflecting a pause after reinforcement.

COGNITION & LATENT LEARNING

• Skinner's Perspective:

  • Considered a "radical behaviorist" who discounted the role of cognition in learning.

• Edward Tolman's Findings:

  • Discovered that learning can occur without reinforcement, indicating a cognitive aspect to learning.

  • Rats in a Maze Experiment:

  • Rats developed a cognitive map of their environment to learn a way out of the maze without food reinforcement.

  • They did not demonstrate their learning until food was placed at the exit after 10 sessions.

  • The rats exited the maze quickly, showing latent learning.

OBSERVATIONAL LEARNING (MODELING)

• Definition: Learning by watching others and then imitating their actions.

• Model: The individual performing the behavior that is being imitated.

SOCIAL LEARNING THEORY

• Developed by: Albert Bandura.

• Overview: Explains how learning occurs without external reinforcement.

  • More than imitation; likely involves internal mental states.

Steps in the Modeling Process

1. Attention: The observer must focus on the behavior being performed.

2. Retention: The observer must be able to remember what they observed.

3. Reproduction: The observer must have the physical ability to perform the observed behavior.

4. Motivation: The observer must want to copy the behavior, which is influenced by the outcomes that happened to the model.

Vicarious Reinforcement and Punishment

• Vicarious Reinforcement: The process where the observer sees the model rewarded, making the observer more likely to imitate the model’s behavior.

• Vicarious Punishment: The process where the observer sees the model punished, which makes the observer less likely to imitate the behavior of the model.

BANDURA’S BOBO DOLL EXPERIMENT

• Study Overview: Bandura's study focused on modeling aggressive and violent behaviors.

• Experiment Setup: Children observed adults acting aggressively towards a 5-foot Bobo doll.

  • The adult was either punished, praised, or ignored for their behavior.

• Children’s Response: Afterward, children were given the opportunity to play with the Bobo doll.

  • If they observed the adult being punished, they were less likely to act aggressively towards the doll.

  • If they saw the adult praised or ignored, they were more likely to imitate the adult's aggressive behavior.

• Conclusion: Children observe and learn from adult behavior, leading to both prosocial and antisocial consequences.

• Today’s Topics for Students’ Choice Lecture:

  • Neurodegenerative Diseases

  • Lasers, Neuroscience, & "Mind Control"

  • Industrial/Organizational Psychology

  • Health Psychology