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
• Thorndikes Pre-1930s Theory Emphasis on
  Practice
• Thorndikes Post-1930 Theory Emphasis on
  Reinforcement
• Overview of Hull's system
• Variables of Hulls System
• Hulls system Input Variables Predictors
• Hulls system Intervening Variables
• Hulls system Output Variables The Predicted
• Modification of Hulls system
• Appraisal of Thorndike's Connectionism
• Appraisal of Hull's Formal Behaviorism

3
Question

• What is the most important factor of Thorndike
  and Hulls learning theory?
• What is the major problem of Thorndikes learning
  theory?
• What is the major problem of Hulls learning
  theory?

4
Edward L. Thorndike(1874-1949) Connectionism

• Thorndikes 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
  -gt 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 responses rather 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 ways if
  its first response does not lead immediately to a
  more satisfying state of affairs -gt 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) elements in 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 little to 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
• Hulls main concern was to derive specific,
  testable hypotheses from the 17 postulates
• Hull summarized the components of learning into 3
  categories
• Conditions(Stimuli) -gt input variables observed
  and measured
• Responses -gt output variables observed and
  measured
• Organism -gt 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
  predicted if psychologists had the right
  information and the right equations.

10
Hulls System
11
Variables of Hulls System
Type Name Meanings
Input Variable N Number of prior reinforcements
Input Variable CD Driver condition
Input Variable S Stimulus intensity
Input Variable w Amount of reward
Input Variable W Work involved in responding
Intervening variables SHR Habit strength
Intervening variables D drive
Intervening variables V Stimulus-intensity dynamism
Intervening variables K Incentive motivation
Intervening variables SER Reaction potential
Intervening variables SI!R Aggregate inhibitory potential
Intervening variables SE!R Net reaction potential
Intervening variables sLr Reaction threshold
Intervening variables sOr Oscillation of reaction potential
Output variables R The occurrence of a response
Output variables StR Response latency
Output variables A Response amplitude
Output variables N Number of nonreinforced trials to extinction
Output variables 0 No response
12
Hulls system Input Variables Predictors

• Input variables are predictors
• They represent the information the psychologist
  needs to correctly predict how 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
Hulls system Intervening Variables

• They intervene between stimulus events and
  response events to 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
Hulls 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 any of them is zero, 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
Hulls 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 gt sLR, a response, R, occurs if sE!R lt
  sLR, no response occurs
• 9. sOR oscillation of reaction potential

16
Hulls 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 gt 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 Hulls 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 Hulls learning theory?
• What is the major problem of Thorndikes learning
  theory?
• What is the major problem of Hulls learning
  theory?