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Learning Defined

Learning Defined . What you think this course is all about, and what this course really deals with may be quite different: many people equate learning only w/human learning ii) learning much more than this GENERAL principles human and nonhuman learning Emphasis on behavior and experience:

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Learning Defined

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  1. Learning Defined • What you think this course is all about, and what this course really deals with may be quite different: • many people equate learning only w/human learning • ii) learning much more than this • GENERAL principles • human and nonhuman learning • Emphasis on behavior and experience: • emphasis on behavior because it is MEASURABLE • I don't know what my cat is thinking • I only know what behaviors it is engaging in • emphasis on behavior based on experience • not biology • not maturation • LEARNING IS: a relatively permanent change in an individual's behavior which is not due to maturation, but is a result of practice or experience

  2. Search for general principles of learning: • Historically, psychologists searched out general principle • basic rules or guidelines for learning • general statements that can be made about learning • Most prominent: B.F. Skinner: Behavior of Organisms (1938) • used animals • first to use "Skinner box“ • What mean by general principles? • very common in other sciences • rules about the behavior • environmental constraints must be specified: conditions under which occur clearly stated • really- dealing with theories of learning rather than true principles or laws • Nature of Scientific theories: • science is an enterprise concerned with gaining information about causality or the relationship between cause and effect (James Mazur)

  3. 4 components of scientific theory • Independent variable = cause • dependent variable = effect • (both IV and DV must be observable, measurable events) • Intervening variables: • Used in order to predict relationship between DV and IV • purely theoretical concepts • cannot be measured or observed directly • e.g.: force, mass, gravity • note: not all psychologists accept use of intervening variables- particularly hard core behaviorists) • Syntax: • rules and definitions that state how independent and dependent variables are to be measured • Specify relationship among IV, Intervening variables & DV • these "better known" as experimental methods

  4. How to judge or evaluate scientific theories: • Testability (Falsifiability) • Simplicity or parsimony • Generality • Fruitfulness • Agreement w/data:

  5. Early Theories: Aristotle (circa 350 BC) • known as first associationist • proposed three principles of association- really elementary theory of memory • contiguity: more closely together (contiguous) in space or time 2 items occur, more likely that thought of one lead to thought of other • similarity: more similar 2 items are in space or time, more likely that thought of one lead to thought of other • contrast: more unlike 2 items are in space/time, more likely that thought of one lead to thought of other

  6. British Associationists or Empiricists : • Include Thomas Hobbes (1651); (2) John Locke (1690); (3) James Mill (1829); (4) John Stuart Mill (1843) • source of all knowledge was sensory experience • people born knowing nothing • gradually gather knowledge via experience • Tabula rasa or blank slate idea (Locke) • opposite of Kant's Nativism • extreme position = Empiricist position • set hypotheses about how old concepts become associated in memory/how new concepts are formed • direct correspondence between experience and memory • experience = sensations • memory = ideas • one-to-one correspondence between simple sensations and simple ideas • idea = form of a sensation • complex ideas: James Mill • two or more simple sensations repeatedly presented together, product of union may be complex idea • once complex idea formed, can also be evoked by process of association from simple sensations or ideas

  7. Thomas Brown (1982): Secondary Principles of association: • attempt to make Mills theory more complete • length of time 2 sentences coexist determines strength of association • liveliness or vividness of sensations also affects strength • frequency of pairings • recency of pairings • freedom from other strong associations • constitutional differences • current emotional states • momentary state of body • individual prior habits • Early learning researchers tested these principles (e.g., Ebbinghaus)

  8. Side Bar: Innate behaivor • Innate versus learned behaviors: • Innate: animal born w/ability to do behavior; behavior is NOT learned • many learned behaviors = derivations, extensions, or variations of innate behavior patterns • many of the features of learned behaviors have parallel in inborn behavior • innate behaviors may place limitations on what can learn • focus on goal-directed or goal-oriented behavior: • purposive • characteristic of both learned and unlearned behaviors

  9. Goal Directed Innate Behaviors: • Reflexes • stereotyped pattern of movement of part of body which can be reliably elicited by presenting appropriate stimulus • Sherrington's Principles of Reflex action • threshold of stimulus intensity to elicit response • as increase intensity of stimulus, the latency between the stimulus and response decreases • IRRADIATION EFFECT • RECIPROCAL INHIBITION: coordination between the muscles during reflexes: • Tropisms and Orientations: • movement or change in orientation of the entire organism • come in 2 major categories: • (a) kineses: random movement • (b) taxes: directed movement • Fixed action patterns • behavior is a part of repertoire of all members of that species/is not due to prior learning • series of behaviors occur in a rigid order • once started, the entire sequence must finish • sign stimulus needed to initiate fixed action patter • Reaction chains: • similar to fixed action patterns • But not have to keep going once start • progression from one behavior to next in series depends on presence of appropriate stimulus • e.g., hermit crab

  10. Pavlov’s original experiment • his experiments measuring salivation in dogs to meat powder: found interesting situation: • dogs began to salivate to presence of the experimenter BEFORE the meat powder was delivered • reacting to the experimenter, or other environmental conditions- NOT just the terminal event itself • iii) thus: • (1) knew FOOD ---> salivation • (2) found: LAB COAT ---> FOOD \ | \ | ---> Salivation • thought was an interesting phenomenon- followed up on it

  11. The basic design: CS ---------> US-------> UR bell food salivation \ | \ | ----> CR: salivation • important variables: • CS = conditioned stimulus: arbitrary stimulus that does not automatically evoke the response • UCS or US = unconditioned stimulus: • nonarbitrary stimulus that does automatically evoke the response • UCR or UR = unconditioned response: the response that is automatically evoked by the US • CR = conditioned response: response that the CR evokes (what learned): May or may not be identical to UR • Crucial aspect for learning: Pairing of CS and US predicts an event

  12. Important (critical) things to note about classical conditioning: • the CS MUST precede the US • the CS MUST predict the US • if the CS does not predict the US, no conditioning occurs • the CR does not have to be identical to the UR • E.g., subtle differences even Pavlov noticed) • may even be opposite: Morphine studies • Any response is a classically conditioned response if it occurs to a CS after that CS has been paired with a US but does NOT occur to a randomly presented CS-US pairing

  13. Types of conditioned responses ) • Eyeblink conditioning: • Conditioned suppression or conditioned Emotional Response (CER) • Galvanic skin response: • taste aversion learning • Conditioned place preference

  14. Acquisition: Number of trials reaches asymptote factor on asymptote: size or intensity of the US stronger US = higher asymptote of conditioning also can affect rate of learning (steepness) Parameters of Classical Conditioning

  15. When you present the CS is important: • Standard pairing: CS, then offset US • Delay conditioning: CS offset, immediate US onset • Simultaneous conditioning: CS + US • Trace conditioning: CS, offset, no stim, then US • Backward conditioning: US then CS

  16. Other parameters • MULTIPLE CS's: Secondary and tertiary CS's • can "chain" together various CS's • that is, can use one CS to predict another CS which predicts US • CR weakens as gets farther away from the US • EXTINCTION: • unpairing of CS-US relation • really, learning not to respond: INHIBITORY • SPONTANEOUS RECOVERY: • reappearance of the CR after extinction • almost a "testing" or left over learning • Generalization and discrimination • Generalization: learn to respond to similar CSs • Discrimination: learn to respond only to specific CS

  17. INHIBITION AND DISINHIBITION: • Inhibition • during the acquisition of CC- any disruption may prevent the occurrence of the CR on any particular trial Buzzer---> CS (bell)---> US (food) \ | \ | \ | --> no UR (Salivation) • Palov called this external inhibition: Some external stimulus blocked inhibited the CR • Disinhibition: • during extinction- opposite occurs • any disruption may bring back the CR on any particular trial Buzzer---> Bell (bell)---> No US (food) \ | \ | \ | -->UR (Salivation) • believed that presentation of distractor stimulus disrupted unstable Inhibitor link that develops during extinction • The more ore stable CS-US association, less affected by distracting S+ • supposedly due to changes in excitation levels

  18. Tests of Inhibition and Disinhibition • Summation Test: • superimpose a stimulus on an ongoing response: • if the strength of CS decreases, that stimulus is inhibitory • this would show that the CS2 is inhibitory, not that there was a change in excitation, since everything leading to excitation was held constant • Retardation or acquisition test • if its harder (takes longer) to make a stimulus excitatory than some neutral stimulus, then the stimulus is inhibitory • NOTE: that the summation test and the retardation of acquisition test are always done together • Inhibitory Gradient test: • if a stimulus is inhibitory, there will be an upside down generalization gradient around it: • Excitatory gradient: responding (CR’s) increase in presence of CS • Inhibitory gradient: responding (CR’s) decrease in presence of CS: • How do you get an animal to respond to these new stimuli to get the inhibitory gradient to elicit the CR? • the inhibitory gradient changes over time: • Change in gradient: • Conditions that produce inhibition: CS+ --------> CR CS- -----> no US \ vs. \ -------> US • really, is just discrimination and generalization • learn that some CS = UR, some CS = no UR

  19. Higher order conditioning • Second Order conditioning • second order US: something that has acquired the ability to act as a US • note: not really neutral, in true sense of word • through pairings of CS with a US, CS becomes reinforcing or "good" to the subject • Next: pair another stimulus w/that CS e.g. CS2---> CS1 ---> US light bell food • animal will learn to respond to light as well as bell • light is predictive of bell, which is predictive of food • can get 3rd order, etc. conditioning as well • happens in "real life" constantly: • tornado = danger: UR = fear (CR to tornado) • tornado siren = tornado • tornado siren = fear • Sensory Preconditioning: • similar to second-order conditioning, except that the two CS's are paired BEFORE the US is introduced • e.g.: pair light and bell first; then pair bell with food • test Bell--> Food; get CR • test Light--> get CR, too • again, light in past has been predictive of bell, which is now predictive of food

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