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PSYC214 Learning and Behaviour - Week 8 Lecture_MELBOURNE

PSYC214 - LEARNING AND BEHAVIOUR WEEK EIGHT LECTURE SUMMARY

1. Overview of Topics

  • Stimulus Control of Behaviour

  • Measurement of Stimulus Control

  • Variables Influencing Stimulus Control

  • Stimulus Discrimination Training

  • Contextual Cues and Conditional Relations

2. Stimulus Control of Behaviour

  • Definition: Contextual stimuli precede and control instrumental behaviours (antecedents).

  • Behaviour: Instrumental behaviours are often driven by antecedent or contextual stimuli.

  • Differences: Responses to the same stimuli can differ between individuals (both humans and animals).

  • Examples:

    • Stopping before crossing the road.

    • Halting at a stop sign.

    • Putting up an umbrella when it rains.

3. Experimental Paradigms to Measure Stimulus Control

  • Video Example: Stimulus discrimination in rats.

  • Key Questions:

    • What is the goal of the rat's behaviour? (Food reward)

    • What is the discriminative stimulus? ("Light off" indicates reinforcement for clockwise turn; "light on" for counter-clockwise turn.)

    • Discriminative Stimulus: An antecedent stimulus that reliably reinforces a behaviour.

4. Reynolds (1961) Experiment with Pigeons

  • Pecking Behaviour:

    • Complex shape (white triangle inside dark circle) prompted increased pecking.

  • Reaction to Single Stimuli:

    • Pecking with single white triangle or dark circle? Examines if the compound stimulus leads to behaviour.

5. Stimulus Discrimination

  • Concept: Demonstrated by different responses to distinct stimuli.

  • Outcome: Pigeons exhibit differential responding showing they treat each stimulus differently.

6. Stimulus Generalization

  • Definition: Tendency to respond to similar stimuli in the same way.

  • Usage: Useful in learning new responses in varied circumstances.

7. Generalization Gradient

  • Guttman & Kalish (1956):

  • Pecking Behaviour with Colour Variance: Measures overall sensitivity of behaviour to changes in stimuli.

    • Steep Gradient: Different responses to certain colours vs. others.

    • Flat Gradient: Similar responses to all stimuli indicating no specific control.

8. Variables Affecting Stimulus Control

  1. Sensory Capacity and Orientation

    • Ability to detect stimuli limits control of behaviour.

    • Sensitivity: Required sensory organs' availability doesn't ensure behaviour control.

  2. Ease of Conditioning

    • Competing cues can impair conditioning (e.g., overshadowing).

    • Example: Relying on specific landmarks for navigation can overshadow learning other cues.

  3. Types of Reinforcement

    • Relation of stimuli in appetitive vs. aversive contexts affects control (e.g., light for food versus tone for shock).

  4. Stimulus Elements vs Configural Cues

    • Elements are individual features (light and tone separate) vs. configural which treats them as a whole (like a symphony).

9. Recap of Principles

  • Learning Application: Not only what to do, but also when to do it.

  • Measurement: Includes assessment of stimulus discrimination and generalization gradients.

  • Influences: Can be affected by detection ability, competing stimuli, reinforcement, and nature of stimuli (single vs compound).

10. Role of Learning in Stimulus Control

  • Generalization: Learning about one stimulus can transfer to similar stimuli.

  • Training:

    • Discrimination Training establishes control over behaviours based on distinct reinforcing conditions.

  • Example: Green traffic light (rewarded, S+) vs. red light (punished, S-).

11. Summary of Learning Factors

  • Discrimination Training: Learning involves excitatory and inhibitory responses.

  • Equivalence training encourages widespread identical responses among various stimuli.

12. Next Steps

  • Upcoming Topic: Week 9 focuses on Extinction.