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Learning

A relatively permanent change in an organism’s behavior due to experience. We learn by association. Our minds naturally connect events that occur in sequence

Simplest forms of learning – habituation and sensitization. What are they? Are they really examples of learning?

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ConditioningConditioning A basic form of learning

Classical Conditioning Learning in which response naturally caused by one stimulus comes to be elicited by a different, formerly neutral stimulus.

Ivan Pavlov Accidentally discovered classical conditioning. His experiments on salivation in dogs turned into research on learning

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Russian physiologist Ivan Pavlov was the first to scientifically study classical conditioning. His work provided a basis for later behaviorists like John Watson and B. F. Skinner

Classical Conditioning

Ivan Pavlov (1849-1936)

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Pavlov’s Experiments

Before conditioning, food (Unconditioned Stimulus, UCS or US) produces salivation (Unconditioned Response, UR). However, the tone (neutral stimulus, NS) does not

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Pavlov’s Experiments

During conditioning, the NS (neutral stimulus = tone) and the US (food) are paired, resulting in salivation (UR). After conditioning, the NS (now Conditioned Stimulus, CS) elicits salivation (now Conditioned Response, CR)

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Stimulus Generalization and Discrimination

The tendency to respond to stimuli similar to the CS is called generalization

Discrimination is the learned ability to distinguish between a conditioned stimulus and other stimuli that do not signal an unconditioned stimulus

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Acquisition (Trials)

Acquisition is the initial stage in classical conditioning in which an association between a neutral stimulus and an unconditioned stimulus takes place

1. In most cases, for conditioning to occur, the neutral stimulus needs to come before the unconditioned stimulus (trace conditioning)

2. The time in between the two stimuli should be about half second.

3. Other acquisition pairings – delay, simultaneous, backward

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Classical Conditioning Applied

Trash Cans and other Objects Altoid

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Extending Pavlov’s Understanding –Cognitive Processes

Early behaviorists contend that learned behaviors of animals were mindless associations aka the Contiguity model – Conditioning will occur whenever NS and UCS are paired (Pavlov and Watson)

However, later behaviorists suggest that animals learn the predictability of a stimulus, meaning they learn expectancy of a stimulus. The Contingency model emphasizes the role of expectation-NS predicts the UCS (Rescorla and Wagner)

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Biological Factors in Conditioning

Pavlov and Watson believed that laws of learning were similar for all animals.

However, later behaviorists later suggested that learning is constrained by an animal’s biology. John Garcia and Conditioned Taste Aversions. Learning can be constrained by biological predispositions

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Biological Predispositions

John Garcia

Garcia showed that the duration between the CS and the US may be long (hours), but yet still result in conditioning. A biologically adaptive CS (taste) led to conditioning and not to others (light or sound). Known as the Garcia effect or Sauce Bernaise Syndrome

Courtesy of John G

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Classical Conditioning in Humans

• Taste aversions Association between taste of a certain food and a feeling of nausea.

• How are taste aversions slightly different than classical, classical conditioning?– May occur often with only a single pairing– Pairing may not be close in time– Speed of learning (role of survival?)

• Preparedness is the notion that humans are predisposed to develop some phobias because they have biological survival value

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• The Baby Albert experiment demonstrated classically conditioned phobia in humans (John Watson and Rosalie Raynor) UCS/UCR/NS-CS/CR GS Baby Albert

• Watson later used conditioning procedures to develop advertising campaigns. Father of brand loyalty and the concept of market niche. Maxwell House campaign made the “coffee break” an American custom

Applications of Classical Conditioning to Humans

John B. Watson

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Classical Conditioning in Humans – Uses in Behavioral Therapy

Systematic Desensitization (Mary Cover Jones) A counterconditioning technique that used to treat phobias. She counterconditioned Watson’s babies. Person learns to relax in presence of stimulus that used to be upsetting (progressive relaxation – Wolpe). Also called exposure therapy. Extreme form is called flooding

Aversive conditioning Associates unpleasant state with unwanted behavior (like Gustavson!). Antabuse and alcohol, bell pad method, Kubrick, Other examples?

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Classical v. Operant Conditioning

Classical conditioning forms associations between stimuli (CS and US). It occurs as an automatic response to a certain stimulus

Operant conditioning (or instrumental) forms an association between behaviors and the resulting events

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Thorndike’s Experiments

Skinner’s experiments extend Thorndike’s law of effect. This states that rewarded behavior is likely to occur again

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Operant Conditioning

• Learning in which an organism’s behavior is followed by a reinforcer (positive or negative) or punishment

• Organism learns to perform behavior in order to gain a reward or avoid a punishment

• Reinforcer A stimulus or event that follows a behavior and makes that behavior more likely to occur again (includes both positive and negative reinforcers)

• Punisher A stimulus or event that follows a behavior and makes that behavior less likely to occur again

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Types of Reinforcement

• Positive reinforcer (+)

– Adds something following a behavior, making that behavior more likely to occur again

– Giving a dog a treat for fetching a ball

• Negative reinforcer (-)

– Removes something unpleasant from the environment following a behavior, making that behavior more likely to occur again

– Taking an aspirin to relieve a headache

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• Immediate Reinforcer Occurs instantly after a behavior. A rat gets a food pellet for a bar press (TV v. studying)

• Delayed Reinforcer Is delayed in time for a certain behavior, e.g. a paycheck at the end of a week

• Continuous Reinforcement Reinforces the desired response each time it occurs (Rapid learning and rapid extinction)

• Partial (Intermittent) Reinforcement Reinforces a response only part of the time and shows greater resistance to extinction (ratio and interval)

Concepts in Reinforcement

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Reinforcement SchedulesFixed-ratio schedule Reinforces a response only after a specified number of responses. “Pause and run” response

Variable-ratio schedule Reinforces a response after an unpredictable number of responses. High unpredictability. (e.g., behaviors like gambling, fishing). Consistently high rate of response, hard to extinguish

Fixed-interval schedule: Reinforces a response only after a specified time has elapsed. (quiz Friday, study Thursday). Response occurs at end in anticipation

Variable-interval schedule: Reinforces a response at unpredictable time intervals, which produces moderate, steady responses. (pop quizzes)

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Operant Chamber

The oper ant chamber (or Ski nner box), comes with a bar or key that an animal manipulat es t o obt ain a reinforcer l ike food or water. The bar or key is connected to devi ces t hat record the animal’s response. Ski nner

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Shaping

Shaping is the operant conditioning procedure in which reinforcers guide behavior towards the desired target behavior through successive approximations

A rat shaped to sniff mines. A manatee shaped to discriminateobjects of different shapes, colors and sizes.

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What about the Brelands?

Instinctual drift/biological predispositions?

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Primary Reinforcer An innately reinforcing stimulus like food or drinkConditioned Reinforcer (or secondary) A learned reinforcer that gets its reinforcing power through association with the primary reinforcer

Wolfe’s Chimp-O-Mat. Other examples?

Discovering Psychology Learning

Primary & Secondary Reinforcers

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Negative Reinforcement

• Negative reinforcement increases the likelihood of a behavior (or strengthens) by removing or preventing a stimulus from occurring

– Escape conditioning

– Avoidance conditioning

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Negative Reinforcement

• What is the aversive stimulus and the behavior being strengthened by its removal? Is the behavior an escape or avoidance response?

– 1. Taking an aspirin to relieve a headache– 2. Feigning a stomach ache to stay home from school– 3. Smoking in order to relieve anxiety– 4. Arriving to class on time to avoid a teacher's glare – 5. Leaving the movie theater if a movie is horrible– 6. Putting on your seatbelt to stop the buzz– 7. Coming home before curfew to avoid trouble– 8. Driving the speed limit through Venice

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Negative Reinforcement is NOT Punishment

• Punishment decreases the occurrence of a behavior (or may)

• Positive punishment (administers aversive stimulus) v. negative punishment (withdraws a desirable stimulus aka omission training)

• Effective punishment– Should occur as soon as possible after the behavior– Should be sufficient, i.e., strong enough– Should be certain, occurring every time the behavior does– Should be consistent and relevant to behavior

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Punishment

1. Results in unwanted fears2. Conveys no information to the organism (appropriate

behavior, e.g., only suppresses behavior)3. Justifies pain to others4. Causes unwanted behaviors to reappear in its absence5. Causes anger and aggression towards the agent6. Causes one unwanted behavior to appear in place of

another

Although there is some justification for occasional punishment (Larzelaere & Baumrind, 2002), it often leads to negative outcomes

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Skinner’s Legacy

• Skinner provides a vocabulary for understanding conditioning and reinforcement and their role in the learning process

• While Skinner accepted inner thought processes and biological underpinnings, he discounted them as a means of changing behavior (a fruitless endeavor). He argued that behaviors were shaped by external influences instead of inner thoughts and feelings

• Ascribed nearly all behavior to conditioning.

• Positive, hopeful and helpful or reductionistic, dehumanizing and dangerous?

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Role of Motivation

Intrinsic Motivation

The desire to perform a behavior for its own sake

Extrinsic Motivation

The desire to perform a behavior due to promised rewards or threats of punishments

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Seligman and Learned Helplessness

• Learned helplessness experiments

• Possible model for depression

– Stability and instability

– Internal v. external

– Global v. specific

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Social Learning Theory

• Social learning theory focuses on what we learn from observing other people (modelling and imitative behavior)

• Bandura's Bobo doll study (1961) indicated that individuals (children) learn through imitating others who receive rewards and punishments– Observational or vicarious learning occurs when we see the

consequences of other people’s behavior– Vicarious reinforcement or vicarious punishment affects

the willingness of people to perform behaviors they learned by watching others and subsequent consequences

– Pro-social and anti-social models

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Observational or Social Learning Theory

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Media and Observational Learning

Gentile, et al., (2004) shows that children in elementary school who are exposed to violent television, videos, and video games express increased aggression.

Multiple studies show both correlation and causal effects

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Causes and Effects of Media Violence

• Observational Learning/Modeling

• Desensitization (psychic numbing)

• Disinhibition• Circular effect• Dangerous world phenomenon• Increased Arousal theory• Priming effect

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Challenges to Behaviorism – The Role of Cognitive Learning

• Evidence of cognitive processes during operant learning comes from rats during a maze exploration in which they navigate the maze without an obvious reward (E.C. Tolman’s rat mazes). Rats develop cognitive maps, or mental representations, of the layout of the maze.

• Such cognitive maps are based on latent learning, which becomes apparent when an incentive is given (Tolman & Honzik, 1930).

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Cognitive Learning Insight and Aha Experience

• Insight is when learning seems to occur in a sudden “flash” as elements of a situation come together. Kohler experiments and “Aha” experiences

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Biological and Evolutionary Bases for

Learning• Possible role of mirror neurons

• Long-term potentiation changes at neural level

• Kandel’s aplysia studies (classical conditioning - ltp and neuromodulators)

• Evolutionary basis for learning. Imitation onset, aversions…