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.