PSY 102 Lecture 7: Learning

• PSY 102: Introduction to Psychology I, Winter 2025, Instructor: Professor Margot Sullivan (she/her)

Classroom Qs

• Feel free to raise hand during class and speak to the professor during breaks for classroom questions
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Lecture 7: Learning

• The topic covered in the lecture is learning

Overview

• The lecture will be covering:
• What is Learning/Basic Forms of Learning
• Classical Conditioning
• Operant Conditioning/Schedules of Reinforcement
• Cognitive Models and Biological Influences on Learning

What is Learning?

• Learning is a change in an organism's behaviour or thought as a result of experience.
• Brains change along with behaviors.
• Principles that explain learned responses in animals explain much of human learning too.
• Learning ranges from simple to complex.

Basic forms of Learning

• Habituation refers to a decrease in response to a stimulus over time.
• Example: Sea Slug (Aplysia) (Eric Kandel, 2000) where if pricked repeatedly, it will begin to ignore the stimulus and there is a progressive decrease in serotonin release at the sea slug's synapses
• Habituation is a behavioural learning effect, while sensory adaptation is a physiological effect.
• Typically, organisms do not habituate to powerful stimuli, such as loud noises or electric shocks.
• Sensitization: Increase in responding over time

Making Connections

• Conditioning involves learning connections between events that occur in an organism's environment, through association

Classical Conditioning

• Ivan Pavlov, a Russian physiologist, studied digestion in dogs (1903-1904).
• Meat powder elicits an automatic response.

Steps of Classical Conditioning

• The general steps include repeatedly pairing meat powder with a neutral stimulus
• Neutral Stimulus (Metronome) + UCS (Meat Powder) = UCR (Salivation)

Summary of Classical Conditioning

• Classical Conditioning contains 5 components:
  • NS = Neutral Stimulus
  • UCS = Unconditioned Stimulus
  • UCR = Unconditioned Response
  • CS = Conditioned Stimulus
  • CR = Conditioned Response

Classical (Pavlovian) conditioning

• Animals respond to a previously neutral stimulus which is paired with another stimulus which elicits an automatic response.

Principles of Classical Conditioning

• Acquisition: Learning phase during which a CR is established. Faster learning occurs when pairing occurs closer together
• Evolutionary adaptive, backward conditioning is difficult to achieve.
• Extinction: Reduction of the CR after the CS is presented repeatedly without the UCS.
• Spontaneous recovery: CR returns after time has passed (no UCS-CS repairing required).
• Renewal effect: Sudden return of the CR following extinction when the animal is returned to the environment in which the CR was acquired.
• Applicable for phobias and can be adaptive.
• Stimulus generalization occurs when similar stimuli elicit the same CR.
• Stimulus discrimination involves the ability to distinguish between one stimulus and similar stimuli, in which response will differ.
• Higher-Order Conditioning: a second conditioned stimulus becomes associated with an initial conditioned stimulus and then evokes the CR by itself. CR1 strongest, CR2 weaker, CR3 even weaker.

Classical Conditioning in Everyday Life

• Advertisers or politicians repeatedly pair their products or themselves with stimuli that elicit positive emotions.

Latent inhibition

• A stimulus often experienced alone (e.g., Trudeau) may be resistant to conditioning.

The Acquisition of Fears and Phobias

• John B. Watson and Rosalie Rayner (1920) conditioned fear in 11-month year old, little Albert, who initially was unafraid of a white rat.

Operant Conditioning

• Learning controlled by the consequences of the organism's behaviour.

Key Differences Between Operant and Classical Conditioning

• Target Behaviour is Elicited automatically in classical and Emitted voluntarily in operant
• Behaviour is Stimuli that precede the behaviour and Consequences that follow the behaviour in operant.
• Behaviour depends primarily on Autonomic nervous system in classical and Skeletal muscles in operant

Thorndike's Law of Effect

• Learning involves an association between a stimulus and response (S-R).
• Rewards strengthen behaviour.
• S → R = Reward
• If consequences are unpleasant, S-R connection weakens and S - - > R = Not Rewarding

Thorndike's Puzzle Box Experiment

• Time to escape decreased gradually over many trials.
• Cats were learning by trial-and-error, builiding up S-R associations.
• Did not correspond to insight learning.

B.F. Skinner

• Designed the Skinner box (operant chamber) to more effectively record operant behaviour.

Operant Conditioning Terminology

• Reinforcers are outcomes that increase the probability of a response.
• Positive reinforcement involves presenting a stimulus.
• Negative reinforcement involves removing a stimulus.
• Punishment is any outcome that decreases the probability of a response
• Positive punishment involves presenting a stimulus.
• Negative punishment involves removing a stimulus.

Schedules of Reinforcement

• Skinner found that animals' behaviours differ depending on the schedule of reinforcement.
• Continuous reinforcement: response is rewarded every time.
• Partial reinforcement: reinforce responses only some of the time.

Continuous vs Partial Reinforcement

• Learning occurs quickly with continuous reinforcement
• However, partial reinforcement is more resistant to extinction.

Schedules vary on Two Dimensions

• Consistency of administering reinforcement whether it is fixed or variable
• Basis of administering reinforcement whether it is a ratio or amount of time

Schedules of Reinforcement

• Fixed Ratio: Reinforced after a specific number of responses. Pattern over time: Rapid responding, then pause.
• Variable Ratio: - The number of responses needed for a reward varies. Pattern over time: High, steady rate without pauses, and yields highest response rate.
• Fixed Interval: Reinforced after a specific amount of time. Pattern over time: Long pause after reinforcement (scalloping effect).
• Variable Interval: Reinforcement is delivered at varying and unpredictable intervals of time. Pattern over time: Low, steady rate without pauses.

Applications of OC for Animal Training

• Shaping: Conditioning a target behaviour by progressively reinforcing (then gradually fading) behaviours that come closer and closer to the target.
• Chaining: Method for teaching a series of behaviours where each response cues the next response. Example: Teaching a dog a sequence of tricks.

Cognitive Models of Learning

• Latent Learning is learning that is not directly observable.
• Tolman & Honzik's Maze study with Rats (1930) conducted an experiment with groups with different reinforcement levels
• One group always received reinforcement at the end of the maze
• One group never received reinforcement and one group didn't receive reinforcement until the 11th day.
• Rats were developing cognitive maps and using them once a reward was present.

Observational Learning

• Learning by watching others, such as models (parents, teachers, siblings, friends)
• Albert Bandura's Bobo doll research (1960s) included kids watching an adult interact with a Bobo doll and exposure to aggressive vs. nonaggressive model triggered aggressive behaviour in the kids.

Mirror Neurons

• Become activated when an animal observes or performs an action.
• Located in the prefrontal cortex.
• Plays a role in observational learning and having empathy for others.

Biological Influences on Learning

• Conditioned taste aversion: Learned avoidance of a particular taste that develops after only one trial with a long delay between CS (food) and UCS (illness) of 6-8 hours and lack of stimulus generalization (very specific).
• John Garcia and colleagues (1966-1980) conducted studies on conditioned taste aversion, in which rats more readily associated taste with nausea vs. pairings with other sensory stimuli.
• Preparedness: we are evolutionarily predisposed to be more afraid of certain things, and Mineka and Cook (1993) conducted experiments where lab-reared monkeys acquired a fear of snakes from observational learning, but not of same videos with flowers or a toy rabbit.