Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 6 Learning Key Terms for Learning • Learning: Relatively durable change in behavior due to experience – Does NOT include temporary changes due to disease, injury, maturation, or drugs, since these do NOT qualify as learning even though they can alter behavior • Reinforcement: Any event that increases the probability that a response will recur • Response: Any identifiable behavior – Internal: Faster heartbeat – Observable: Eating, scratching Classical Conditioning Sovfoto Ideas a of classical conditioning originate from old philosophical theories, however it was a Russian physiologist Ivan Pavlov who elucidated classical conditioning. His work became seminal for later behaviorists like John Watson and B. F. Skinner. Ivan Pavlov (1849-1936) Classical Conditioning (or Pavlovian Conditioning) • Classical Conditioning is a type of learning in which a stimulus acquires the capacity to evoke a response that was originally evoked by another stimulus. • Ivan Pavlov was a Russian physiologist who was originally studying digestion in dogs. • Used dogs to study salivation when dogs were presented with meat powder Pavlov’s Experiments During conditioning, neutral stimulus (tone) and US (food) are paired resulting in salivation (UR). After conditioning neutral stimulus (now Conditioned Stimulus, CS) elicits salivation (now Conditioned Response, CR) The classical conditioning procedure. Classical Conditioning: More Terminology • Trial = pairing of UCS and CS • Acquisition = initial stage in learning • Stimulus contiguity = occurring together in time and space ! • Classical Conditioning in Everyday Life – – – – Conditioned fears Other conditioned emotional responses Conditioning and physiological responses Conditioning and drug effects – F 6.6 Processes in Classical Conditioning • Extinction: when the CS is weakened • Spontaneous Recovery: when an extinct CS recurs when paired with the UCS. • Stimulus Generalization: when we respond to similar to the original UCS • Discrimination: when we respond to a specific stimulus • Higher-order conditioning: when a CS has the same effect as a UCS and establishes new conditioning. • Applications of classical conditioning – Pavlov and persuasion: the use of images and products in advertising Classical Conditioning in Humans • Phobia: Fear that persists even when no realistic danger exists (e.g., arachnophobia (fear of spiders; see the movie!)) • Conditioned Emotional Response (CER): Learned emotional reaction to a previously neutral stimulus • Desensitization: Exposing phobic people gradually to feared stimuli while they stay calm and relaxed • Vicarious Classical Conditioning: Learning to respond emotionally to a stimulus by observing another’s emotional reactions Applications of Classical Conditioning Brown Brothers Watson used classical conditioning procedures to develop advertising campaigns for a number of organizations including Maxwell House, making “coffee break” an American custom. John B. Watson The Little Albert Experiment • Little Albert and John Watson • John Watson in a famous (and perhaps unethical) experiment conditioned “Little Albert” to fear a white rat. Albert generalized this conditioning to other white furry objects. Nobody knows what eventually happened to Little Albert. Operant Conditioning or Instrumental Learning • Edward L. Thorndike (1913) – the Law of Effect: If a response to a stimulus is pleasant, the association between stimulus and response is strengthened • B. F. Skinner – most influential figure in Psychology – Operant Conditioning: reinforcement occurs when an event following a response increases an organism’s tendency to make that response. Basic Processes in Operant Conditioning Shaping consists of reinforcement of closer and closer approximations of a desired response. • Extinction is the gradual weakening and disappearance of a response when a reinforcer is no longer provided • Stimulus Generalization occurs when a response occurs to stimuli other than the original stimulus used in conditioning • Stimulus Discrimination occurs when no response is given to a similar stimuli. Table 6.1 Comparison of Basic Processes in Classical and Operant Conditioning Operant & Classical Conditioning 1. Classical conditioning forms associations between stimuli (CS and US). Operant conditioning on the other hand forms association between behaviors and resulting events. 23 Reinforcement: Consequences that Strengthen Responses • Delayed Reinforcement – Longer delay, slower conditioning • Primary Reinforcers – Satisfy biological needs • Secondary Reinforcers – Conditioned reinforcement Schedules of Reinforcement • Continuous reinforcement • Intermittent (partial) reinforcement • Ratio schedules – Fixed: reinforced after a specific number of responses. – Variable: reinforced after an undetermined number of responses. • Interval schedules – Fixed: reinforced after a specific amount of time. – Variable: reinforced after a varying amount of time Schedules of Reinforcement 26 Consequences: Reinforcement and Punishment • Increasing a response: – Positive reinforcement = response followed by rewarding stimulus – Negative reinforcement = response followed by removal of an aversive stimulus • Escape learning • Avoidance learning • Decreasing a response: – Punishment – Problems with punishment – third variable problem and correlation between punishment and aggression Reinforcement in a token economy. This graph shows the effects of using tokens to reward socially desirable behavior in a mental hospital ward. Desirable behavior was defined as cleaning, bed making, attending therapy sessions, and so forth. Tokens earned could be exchanged for basic amenities such as meals, snacks, coffee, game-room privileges, or weekend passes. The graph shows more than 24 hours per day because it represents the total number of hours of desirable behavior performed by all patients in the ward. (Adapted from Ayllon & Azrin, 1965.) A Token Economy Fig. 8.15 Poker chips normally have little or no value for chimpanzees, but this chimp will work hard to earn them once he learns that the “Chimp-O-Mat” will dispense food in exchange for them. Operant vs. Classical Conditioning 31 Observational Learning: Basic Processes • Albert Bandura (1977, 1986) – Observational learning – F 6.24 – Vicarious conditioning • 4 key processes – – – – attention retention reproduction motivation • acquisition vs. performance Observational Learning and the Media Violence Controversy • Studies demonstrate that exposure to TV and movie violence increases the likelihood of physical aggression, verbal aggression, aggressive thoughts, and aggressive emotions • The association between media violence and aggression is nearly as great as the correlation between smoking and cancer – F 6.26 – third variable problem Comparison of the relationship between media violence and aggression to other correlations.