The Effects of Behavior : Thorndike and Hull

1. The Effects of Behavior :Thorndike and Hull SNU CSE 2008-22937 Son, Suil

2. Contents • Edward L. Thorndike : Connectionism • Thorndike’s Pre-1930s Theory : Emphasis on Practice • Thorndike’s Post-1930 Theory : Emphasis on Reinforcement • Overview of Hull's system • Variables of Hull’s System • Hull’s system : Input Variables: Predictors • Hull’s system : Intervening Variables • Hull’s system : Output Variables : The Predicted • Modification of Hull’s system • Appraisal of Thorndike's Connectionism • Appraisal of Hull's Formal Behaviorism

3. Question • What is the most important factor of Thorndike and Hull’s learning theory? • What is the major problem of Thorndike’s learning theory? • What is the major problem of Hull’s learning theory?

4. Edward L. Thorndike(1874-1949) : Connectionism • Thorndike’s experiment : Puzzle Boxes and Animal Intelligence • Cat can not open the puzzle boxes • Animals were allowed to see a trained animals behavior • They will not learn that behavior • Animals learn through trial and error. • Connection between the response and the situation • Contiguity or Reinforcement • Contiguity : an association is formed between stimuli and responses • Reinforcement : the consequences of the behavior • leads to pleasant consequences • eliminates something unpleasant

5. Thorndike's Pre-1930s Theory: Emphasis on Practice • Emphasizes experimentation rather than introspection • Emphasizes behavior rather than thought • Learning consists of the formation of bonds between stimuli and responses : bonds that take the form of neural connections -> connectionism • Learning invloves stamping in of stimulus-response connections • Forgetting invloves stamping out connections • Three important variables • recency • frequency • Contiguity

6. Thorndike's Pre-1930s Theory • Law of Exercise • Bonds between stimuli and responses are strengthened through being exercised "frequently," "recently," and "vigorously" • Law of Effect • The most important law • A connection is stamped in its consequences(its effects) than how often it is exercised • 1. Responses just before a satisfying state of affairs are more likely to be repeated • Satisfiers • 2. Responses just before an annoying state of affairs are more likely not to be repeated • Annoyers • A model of instrumental learning • The connection is formed between the stimulus and the responsesrather than between the reward and the response • Law of Readiness • This law has to do mainly with the learner's motivation (forces that lead to behavior) • Certain behaviors are more likely to be learned than others

7. Thorndike's Pre-1930s Theory • Subsidiary Laws • 1. Multiple Responses • The organism will respond in a variety of waysif its first response does not lead immediately to a more satisfying state of affairs -> trial and error • 2. Set or Attitude • Learning is partly a function of attitude or set • 3. Prepotency of Elements • It is possible for a learner to react only to the significant(prepotent) elementsin a problem situation • 4. Response by Analogy • When a person is placed in a novel situation, they transfer the situation to similar one • theory of identical elements • 5. Associative Shifting • stimulus substitution • It is possible to shift a response from one stimulus to another.

8. Thorndike's Post-1930 Theory: Emphasis on Reinforcement • He made some major modifications on his theory • Repeal of Law of Exercise • Mere repetition does not cause learning • realized through experimentation with humans • Half a Law of Effect • Satisfier strengthen the connection • Annoying outcomes do relatively littleto the strength of a connection • Learning by Ideas • Account observation about human learning • Thoughts or ideas are important in human learning • Investigated Two additional concepts • 1. principle of belongingness • If two or more elements are seen as belonging together, they are more easily learned • 2. spread of effect • A response is followed by as satisfying state of affairs, other related responses also seem to be affected.

9. Overview of Hull's system • Hull is the most ambitious of the behavior theorists • Hull dream to use the rules of logic and of experimentation to discover and to deduce the laws that govern human behavior • He designed hypothetico-deductive system • based on 17 laws(postulates) • All theorems and corollaries derived from 17 postulates • Hull’s main concern was to derive specific, testable hypotheses from the 17 postulates • Hull summarized the components of learning into 3 categories • Conditions(Stimuli) -> input variables : observed and measured • Responses -> output variables : observed and measured • Organism -> intervening variables : purely hypotherical • inferred from input and output • What might be happening between the presentation of a stimulus and the occurrence of a response • He believed that all behavior consists of S-R connections • He believed that human behavior could be predictedif psychologists had the right information and the right equations.

10. Hull’s System

11. Variables of Hull’s System

12. Hull’s system : Input Variables: Predictors • Input variables are predictors • They represent the informationthe psychologist needs to correctly predicthow a person will respond • Input variables represent a stimulus. • Complex product of a large number of preceding events • N : Number of prior reinforcements • How many times in the past the S-R bond in question has been reinforced • S : stimulus intensity • Something about the physical intensity of the stimulus • CD : driver condition • the drive conditions of the organism • w : amount of reward • W : work invloved in responding • the amount of work required in responding • The major difficulties is that the psychologist needs a tremendous amount of knowledge about the subject's experiences.

13. Hull’s system : Intervening Variables • They intervene between stimulus events and response eventsto determine whether a response will occur for a stimulus. • A mathematical description of S-R relationships • 1. sHr : habit strength • the most important • the strength of the bond between a specific stimulus and response • a function of reinforcement rather than of simple repetition. • 2. D : drive • Drive is a motivational concept closely tied with reinforcement. • Primary drives : Those associated with physiological needs such as the need for food or water • Secondary drives : Conditioned to primary drives through contiguity - high grades or money • Two components • 1. drive proper • 2. inanition component • 3 central functions • 1. It provides for reinforcement, without which learning would not occur • 2. It activates habit strength • 3. Drive stimuli become attached to specific behaviors through learning

14. Hull’s system : Intervening Variables • 3. V : stimulus-intensity dynamism • determine the probability of a response • 4. K : incentive motivation • is determined by amount of reward( w as an input variable) • drive alone could not account for motivation • 5. sEr : reaction potential • sEr = sHr * D * V * K • if the value for anyof them iszero, reaction potential will also be zero. And a response will not occur • identical changes in one of these variables will have different absolute effects, depending on the values of the other variables. • a minimum amount of potential is required before behavior will take place. • Increasing reaction potential will be reflected in shorter response latency(StR), more response amplitude(A), and longer extinction time(n)

15. Hull’s system : Intervening Variables • 6. sE!R : net reaction potential • prior reinforcements or intensity of the stimulus • the result of subtracting the individual's tendency not to respond • 7. sI!R : aggregate inhibitory potential • the tendency that the organism has not to respond • reactive inhibition plus conditioned inhibition • Its effect is to lower the net reaction potential until eventually the response no longer occurs. • 8. sLR : reaction threshold • the magnitude that net reaction potential must exceed before a response will occur • If sE!R > sLR, a response, R, occurs; if sE!R < sLR, no response occurs • 9. sOR : oscillation of reaction potential

16. Hull’s system : Output Variables : The Predicted • Variables • stR : response latency • A : response amplitude • n : the number of nonreinforced responses that would occur before extinction • R : the occurrence of a response • 0 : nonoccurrence of response • If sEr > sLR, then R • sEr = (sHr * D * V * K) - sI!R • If net reaction potential is greater than the threshold, a response will occur • net reaction potential is the product of habit strength, drive, stimulus-intensity dynamism, and incentive motivation, minus aggregate inhibitory potential

17. Modification of Hull’s system • Fractional Antedating Goal Reactions • A conditioned response made by an organism before the actual goal reaction • Stimuli that maintain behavior toward a goal • Habit-Family Hierarchies • an individual will learn a number of different responses for the same stimulus. • each response will lead to the same goal • Family - same goal • Hierarchy • one alternative will usually be preferred over another • reaction potential is higher

18. Appraisal of Thorndike's Connectionism • His laws and principles present a relatively clear picture of his view of learning • Learning consists of the formation of physiological bonds or connections between stimuli and responses • Humans arrive at appropriate responses largely through trial and error • Made significant contributions in the practical application of psychological principles, particularly in teaching • Critics • His theory is based on informal observation • He appealed to vague, internal states as a basis for explaining learning • annoying state • satisfying state

19. Appraisal of Hull's Formal Behaviorism • An organism placed in the same situation on different occasions will generally respond in the same way each time • If the response is different but the situation is identical, it means that the organism has changed • Main problem is the near impossibility of arriving at precise mathematical functions for each of the variables in the equation. • Despite the impressive logic and mathematics that are fundamental to the Hull system, the theory does not fare particularly well with respect to some of human learning criteria • But Hull's system contributed in many tangible ways to the advancement of psychological theory • Introducing concepts such as fractional antedating goal reactions • Hull has profoundly influenced how psychological investigations are conducted • The importance of reinforcement

20. The End • Thank you

21. Question • What is the most important factor of Thorndike and Hull’s learning theory? • What is the major problem of Thorndike’s learning theory? • What is the major problem of Hull’s learning theory?