Exam 2 Results • Top Score: 49 • Mean: 35.80 • Bimodal: 34 and 37 Learning • Median: 36 • Standard Deviation: 5.81 • To calculate your approximate grade, divide 49 by Chapter 8 your score. – Example: • 36/49 = 73.5% = C 1 2 Learning Learning How Do We Learn? Operant Conditioning . Skinner’s Experiments Classical Conditioning . Extending Skinner’s . Pavlov’s Experiments Understanding . Extending Pavlov’s . Skinner’s Legacy Understanding . Contrasting Classical & Operant . Pavlov’s Legacy Conditioning 3 4 Learning Definition Learning by Observation Learning is a relatively permanent change in an organism’s behavior due to experience. Bandura’s Experiments . Applications of Observational Learning is more flexible in comparison to the Learning genetically-programmed behaviors of Chinooks, for example. 5 6 1 How Do We Learn? Stimulus-Stimulus Learning Learning to associate one stimulus We learn by association. Our minds with another. naturally connect events that occur in sequence. 2000 years ago, Aristotle suggested this law of association. Then 200 years ago Locke and Hume reiterated this law. 7 8 Stimulus-Stimulus Learning Response-Consequence Learning Learning to associate one stimulus Learning to associate a response with another. with a consequence. 9 10 Response-Consequence Learning Classical Conditioning Learning to associate a response Ideas of classical conditioning originate from old with a consequence. philosophical theories. However, it was the Russian physiologist Ivan Pavlov who elucidated classical conditioning. His work provided a basis for later behaviorists like John Watson and B. F. Skinner. Sovfoto 11 Ivan Pavlov (1849-1936) 12 2 Pavlov’s Experiments Pavlov’s Experiments Before conditioning, food (Unconditioned During conditioning, the neutral stimulus (tone) Stimulus, US) produces salivation and the US (food) are paired, resulting in (Unconditioned Response, UR). However, the salivation (UR). After conditioning, the neutral tone (neutral stimulus) does not. stimulus (now Conditioned Stimulus, CS) elicits salivation (now Conditioned Response, CR) 13 14 Acquisition Acquisition Acquisition is the initial stage in classical The CS needs to come half a second before the US conditioning in which an association between a neutral stimulus and an unconditioned for acquisition to occur. stimulus takes place. In most cases, for conditioning to occur, the neutral stimulus needs to come before the unconditioned stimulus. The time in between the two stimuli should be about half a second. 15 16 Extinction Spontaneous Recovery When the US (food) does not follow the CS After a rest period, an extinguished CR (salivation) (tone), CR (salivation) begins to decrease and spontaneously recovers, but if the CS (tone) persists eventually causes extinction. alone, the CR becomes extinct again. 17 18 3 Stimulus Generalization Stimulus Discrimination Tendency to respond to Discrimination is the learned ability to distinguish stimuli similar to the CS is between a conditioned stimulus and other stimuli that do not signal an unconditioned stimulus. called generalization. Pavlov conditioned the dog’s salivation (CR) by using miniature vibrators (CS) on the thigh. When he subsequently stimulated other parts of the dog’s body, salivation dropped. 19 20 Extending Pavlov’s Understanding Cognitive Processes Pavlov and Watson considered consciousness, Early behaviorists believed that learned or mind, unfit for the scientific study of behaviors of various animals could be reduced psychology. However, they underestimated to mindless mechanisms. the importance of cognitive processes and biological constraints. However, later behaviorists suggested that animals learn the predictability of a stimulus, meaning they learn expectancy or awareness of a stimulus (Rescorla, 1988). 21 22 Biological Predispositions Biological Predispositions Pavlov and Watson believed that laws of learning were similar for all animals. Therefore, a pigeon and a person do not differ in their learning. Courtesy of John Garcia John of Courtesy Garcia showed that the duration However, behaviorists later suggested that between the CS and the US may be learning is constrained by an animal’s biology. long (hours), but yet result in conditioning. A biologically adaptive John Garcia CS (taste) led to conditioning and not to others (light or sound). 23 24 4 Biological Predispositions Pavlov’s Legacy Even humans can develop classically to conditioned nausea. Pavlov’s greatest contribution to psychology is isolating elementary behaviors from more complex ones through objective scientific procedures. Ivan Pavlov (1849-1936) 25 26 Applications of Classical Conditioning Two Famous John Watson Quotes • “Psychology as the behaviorist views it is a purely objective experimental branch of natural science. Its theoretical goal is the prediction and control of behavior. Watson used classical Introspection forms no essential part of its methods, nor is the scientific value of its data dependent upon the readiness with which they lend themselves to conditioning procedures to interpretation in terms of consciousness. The behaviorist, in his efforts to get a develop advertising unitary scheme of animal response, recognizes no dividing line between man and brute. The behavior of man, with all of its refinement and complexity, forms campaigns for a number of only a part of the behaviorist's total scheme of investigation.” • “Give me a dozen healthy infants, well-formed, and my own specified organizations, including world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select -- doctor, Maxwell House, making the lawyer, artist, merchant-chief and, yes, even beggar-man and thief, “coffee break” an American Brothers Brown regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors. I am going beyond my facts and I admit it, custom. but so have the advocates of the contrary and they have been doing it for many thousands of years.”(1930) John Broadus Watson See also, “Little Albert” experiment 27 28 Applications of Classical Operant & Classical Conditioning Conditioning . Alcoholics may be conditioned (aversively) 1. Classical conditioning by reversing their positive-associations with forms associations alcohol. between stimuli (CS . Through classical conditioning, a drug (plus and US). Operant its taste) that affects the immune response conditioning, on the may cause the taste of the drug to invoke the other hand, forms an immune response. association between behaviors and the resulting events. 29 30 5 Operant & Classical Conditioning Skinner’s Experiments Skinner’s experiments extend Thorndike’s . Classical conditioning involves respondent thinking, especially his law of effect. This law behavior that occurs as an automatic states that rewarded behavior is likely to occur response to a certain stimulus. Operant again. conditioning involves operant behavior, a behavior that operates on the environment, producing rewarding or punishing stimuli. Yale University Library University Yale 31 32 Operant Chamber Operant Chamber Using Thorndike's law of effect as a starting The operant chamber, point, Skinner developed the Operant chamber, or Skinner box, comes or the Skinner box, to study operant with a bar or key that rd conditioning. 3 an animal manipulates to obtain a reinforcer Walter Dawn/ Photo Researchers, Inc. Researchers, Photo Dawn/ Walter like food or water. The , 2005. Used with permission with Used ,2005. bar or key is connected Domjan to devices that record the animal’s response. The Essentials of Conditioning and Learning, Learning, and Conditioning of Essentials The by Thomson Learning, Wadsworth Division Wadsworth Learning, Thomson by From From Edition by Michael P. P. Michael by Edition 33 34 Shaping Types of Reinforcers Shaping is the operant conditioning procedure Any event that strengthens the behavior it in which reinforcers guide behavior towards the follows. A heat lamp positively reinforces a desired target behavior through successive meerkat’s behavior in the cold. approximations. Khamis Ramadhan Fred Fred Bavendam / Panapress / Peter Arnold, Inc. Arnold, /Peter / Getty Images /Getty Reuters/ Corbis Reuters/ A rat shaped to sniff mines. A manatee shaped to discriminate objects of different shapes, colors and sizes. 35 36 6 Primary & Secondary Reinforcers Immediate & Delayed Reinforcers . Primary Reinforcer: An innately reinforcing . Immediate Reinforcer: A reinforcer that stimulus like food or drink. occurs instantly after a behavior. A rat gets a food pellet for a bar press. Conditioned Reinforcer: A learned . Delayed Reinforcer: A reinforcer that is reinforcer that gets its reinforcing power delayed in time for a certain behavior. A through association with the primary paycheck that comes at the end of a week. reinforcer. We may be inclined to engage in small immediate reinforcers (watching TV) rather than large delayed reinforcers (getting an A in a course) which require 37 consistent study. 38 Reinforcement Schedules Ratio Schedules 1. Continuous Reinforcement: Reinforces the . Fixed-ratio schedule: Reinforces a response desired response each time it occurs. only after a specified number of responses. e.g., piecework pay. 2. Partial Reinforcement: Reinforces a . Variable-ratio schedule: Reinforces a response only part of the time. Though this response after an unpredictable number of results in slower acquisition in the responses. This is hard to extinguish because beginning,