Transcript Learning
A Brief Introduction to Learning Theory The concept of learning is fundamental to education • We can teach. • We can re-teach. • We can teach alternatives. • Experiences are key to learning: – We learn by making associations between stimuli. One Definition of Learning • A relatively permanent change in an organism’s behavior in a particular situation due to experience. – The change is brought about by repeated experiences in that situation. – The change cannot be explained by native response tendencies (i.e., instincts, reflexes), maturation, or temporary states of the organism ( e.g., fatigue, substance-induced altered states) Types of Learning • Habituation – Learning NOT to respond to common stimuli in env. • Classical or Pavlovian Conditioning – Association of an involuntary response with the environmental cues that precede the response. • Operant or Instrumental Conditioning – Association of behavior with the positive or negative consequence that follows the behavior. • Observational Learning – Reproducing behavior after seeing it produced by another organism. Classical (Pavlovian) Conditioning • Pavlov was a medical doctor who received a Nobel prize in 1904 for his work on the digestive system. • While studying the digestive system of dogs, he observed what he termed “psychic secretions.” – The dogs would salivate not just to the food presented, but to the person who fed them, to the light being turned on in the room prior to feeding, ... • Being a good scientist, he studied the phenomenon, making systematic observations and recording his findings. Terms in Classical Conditioning • Respondent behavior – Automatic responses (e.g., salivation, tearing to onion) • Unconditioned (not learned) stimulus – a stimulus that produces an automatic response on the part of an organism with no learning involved. • Unconditioned (not learned) response – An organism’s response to an unconditioned stimulus. • Neutral stimulus – A stimulus that does not evoke any particular response in an organism, other than maybe an alert response. Terms in CC 2 • Conditioned stimulus – What the neutral stimulus becomes after the acquisition phase of conditioning. – Will revert to a neutral stimulus after extinction. • Conditioned response – A learned response that occurs in response to a conditioned or learned stimulus. – This response is similar to but not as strong as the unconditioned response. For example, Pavlov’s dog produced less saliva in response to the bell than to the food. Phases in Conditioning • Acquisition – Learning the association (e.g., CS UCS; Behavior consequence) • Extinction – “ Forgetting” the association • Spontaneous Recovery – Responding after Extinction with no new conditioning • Generalization – Responding to similar stimuli/environment • Discrimination – Learning to respond to only specific stimuli Operant (Instrumental) Conditioning • Another type of associative learning – Behavior and its consequence – Has same five phases as Classical Conditioning • Law of effect (Thorndike): – Behavior that is followed by a reinforcer is more likely to re-occur; behavior followed by punishment is less likely to re-occur – Apples to operant behavior Shaping • Using reinforcers to “shape” or guide behaviors through closer and closer approximations to target behavior. • Successive approximations • Phases – Acquisition, extinction, spontaneous recovery, generalization, discrimination Principles of Reinforcement • Reinforcer – Anything that strengthens the behavior it follows – There are positive and negative reinforcers • Primary reinforcers - biologically significant • Secondary reinforcers - learned • Immediate versus delayed reinforcement – Too long a delay and no conditioning occurs generally – Humans work for delayed reinforcement, sometimes Schedules of Reinforcement • Continuous reinforcement – Quick acquisition, quick extinction, rare in real life • Partial Reinforcement – Slower acquisition – More resistant to extinction – Four partial reinforcement schedules • • • • Fixed-ratio Variable-ratio Fixed-interval Variable-interval Ratio Schedules • Fixed-Ratio – Behavior reinforced after preset number of responses – Highest rate of responding, b/c resting reduces rewards – Brief post-reinforcement pause • Variable-ratio – Behavior reinforced after unpredictable number of responses (gambling) - how – High rate of responding – Post-reinforcement pause not as regular Interval Schedules • Fixed-Interval – First behavior after fixed time period reinforced – Rate of responding increases as reinforcement time nears, then pause; note scallop pattern • Variable-ratio – First behavior after unpredictable time period reinforced – Slow but steady rate of responding – No obvious pauses just as variable-ratio (Handout 8-5) Punishment • An event that decreases the behavior it follows. – Opposite of reinforcement – Presentation and removal punishment – Immediate and sound punishment most effective • Drawbacks – – – – Suppressed rather than forgotten - emerges when safe Correlation with aggression or modeling aggression May result in fear, anger, learned helplessness Does not indicate what desired behavior is; more effective when combined with reinforcement (handout) Skinner’s legacy • Operant conditioning is used in most settings: – – – – In schools At work (profit sharing, bonuses) At home (parenting, spending) At play Observational Learning • Learning by observing and imitating the behavior of others (Albert Bandura) • Involves modeling • Internalizing of model: high status, successful, consistent, consequences of model’s behavior • Recreation of model’s behaviors Observational Learning • Helps to understand aggressive, negative behaviors (e.g., fighting) and prosocial behaviors • Behavior of parents and high status models important