Unit – XI Educational Psychology

S. NoTitleP. No
01Educational Psychology3
02Heredity and Environment5
03Growth and Development9
10Concept Formation75
16Thinking, Reasoning and Problem-Solving96
18Individual Differences109
19Mental Health112
20Guidance and Counselling115

4. Learning


  • Learning is a permanent change in behavior.
  • It is a result of activity, training, practice or experience.
  • The learning process involves a motive or drive, an attractive goal and a block to the attainment of the goal.

Domains of Learning:

1. Cognitive Domain:

      The learning is expected to changes in one’s cognitive behaviour. It is characterized by ‘thinking’ aspects of one’s behaviour.  Changes are brought by activities like thinking, reasoning, memorizing, explaining, summarizing etc.

2. Affective Domain:

      The learning is expected to changes in one’s affective behaviour. It is characterized by ‘feeling’ aspects of one’s behaviour. Changes are brought by activities like feeling happy, sad, angry, likes, dislikes etc.

3. Conative Domain:

      The learning is expected to changes in one’s conative behaviour. It is characterized by ‘doing’ aspects of one’s behaviour. Changes are brought by activities like walking, running, eating, drinking, seeing etc.

Learning Theories:

  • There are two categories.
  • Association Theories
  • Cognitive Theories

Association Theories:

  • They are known as Stimulus Response (S-R) Theories.
  • Learning is a connection between Stimuli and Response.
  • It emphasizes drill and practice aided by reinforcement.

SR Theories without Reinforcement:

  1. Pavlov’s Classical Conditioning Theory
  2. Watson’s Classical Conditioning Theory
  3. Guthrie’s Theory of Association by Contiguity

SR Theories with Reinforcement:

  1. Thorndike’s Trial and Error Learning
  2. Hull’s Drive Reduction Theory
  3. Skinner’s Operant Conditioning

SR Theories without Reinforcement:

1. Pavlov’s Classical Conditioning Theory:

  • It is called as ‘Stimulus Substitution’ or ‘Conditioned Response Theory’ or ‘Learning by Conditioning’.
  • Conditioning is the modification of the natural response.
  • Response can be modified by substituting a particular stimulus with a different stimulus.
  • ‘It is a learning process whereby an artificial stimulus is able to behave like a natural stimulus when both natural and artificial stimuli are presented together. In this kind of leaning, association plays a great role since the individual responds to an artificial stimulus because he associates it with the natural stimulus.’


  • The sound of bell is paired with food a number of times to a dog.
  • The dog secretes saliva on hearing the bell sound only.

Stage – I:

  • Unconditioned Stimulus (UCS) (i.e) Food – Unconditioned Response (UCR) (i.e) Saliva
  • Conditioned Stimulus (CS) (i.e) bell sound –             No Response (NR)


  • Conditioned Stimulus (CS) (i.e.) bell sound –            Conditioned Response (CR) (i.e) Salivation
  • Unconditioned Stimulus (UCS) (i.e.) Food


  • Conditioned Stimulus (CS) (i.e.) bell sound  -Conditioned Response (CR) (i.e) Salivation

Educational Implications:

  • Classical conditioning is used in language learning by associating words with pictures.
  • It involves the use of audio-visual aids in teaching.
  • Teacher can cultivate positive attitude among the students by applying this theory.
  • Reinforcement can increase learning process.

2. Watson’s Classical Conditioning Theory:

  • J.B. Watson was the founder of American behaviorism.
  • He stressed the importance of environment in learning.
  • When a stimulus and Response occur at the same time in close contiguity the connection between stimulus and Response is strengthened.


  • A little baby named Albert was given a rabbit.
  • He liked to touch the rabbit’s fur.
  • A loud noise was produced as soon as the baby touched the rabbit.
  • At first, the baby was frightened.
  • After many times, the baby gave the fear responses.
Erasing Fear Memories | Operant conditioning, Psychology experiments, Ap  psychology

3. Guthrie’s Theory of Association by Contiguity:

  • Guthrie’s theory specifies that “A combination of stimuli which has accompanied a movement will on its recurrence tend to be followed by that movement.”
  • He propounded the principle of Proximity.
  • His theory is called as “One trial learning.”
  • All learning is done within a single exposure to a situation.


  • A Cat was put in a box with a small pole.
  • The cat could open the door by touching the pole.
  • Whenever the Cat put in the box, the Cat repeated its previous behavior.
behavioranalysishistory / Guthrie, Edwin

S-R Theories with Reinforcement:

1. Thorndike’s Trial and Error Learning:

  • It is called as ‘Thorndike’s Connectionism’ or ‘S-R Bond Theory’.
  • Learning is the result of habits forming between stimuli and responses.
  • Learning takes place through random repetitions through trial and error.
  • The learner selects the proper responses and connects or associates them with adequate stimuli.
  • Thorndike says ‘Learning is connecting. The mind is man’s connection system’.


  • A cat learns to escape to get a fish outside the box after many trials and errors.
  • The situation is described by Thorndike himself as ‘It tries to squeeze through any opening and claws at everything it reaches’.

Thorndike’s Laws of Learning:

1. Law of Readiness:

  • It refers to learner’s preparation to participate in the learning process.
  • The law states “When any conduction unit is ready to conduct, for it do so is satisfying. When a conduction unit is not ready to conduct. for it to conduct is annoying. When any conduction is ready to conduct, for it not to do so is annoying”.

(e.g.) motivation – You can lead a horse to water but you cannot make it drink.

2. Law of Effect:

  • Learning takes place properly, when it results in satisfaction and pleasure.
  • The law states “When a modifiable connection between a stimulus and response is made and is accompanied or followed by a satisfying state of affairs the strength of connection is increased. When a connection between stimulus and response is made and accompanied or followed by an annoying state of affairs, its strength decreases”.

(e.g.) rewards – Success leads to further success.

3. Law of Exercise or Law of Frequency:

  • Learning is strengthened, if it is practiced a number of times.

(e.g.) Practice makes a man perfect.

  • Law of use:
  • It refers to the strengthening the learning by repeated practice.
  • It states that “When a modifiable connection is made between a situation and response that connection strength is increased if it is practised.”
  • Law of Disuse:
  • It refers to that learning will be weakened, when the practice is discontinued.
  • It states that “When a modifiable connection is not made between a situation and response, during a length of time, that connection’s strength is decreased.”

4. Law of Multiple – Response:

            According to it, the organism varies or changes its response till an appropriate behaviour is hit upon. If the individual wants to solve a puzzle, he is to try in different ways rather than mechanically persisting in the same way.

5. The Law of Set or Attitude:

            Learning is guided by a total set or attitude of the organism, which determines not only what the person will do but what will satisfy or annoy him. For instance, unless the cricketer sets himself to make a century, he will not be able to score more runs.

6. Pre- potency of Elements:

            According to this law, the learner reacts selectively to the important or essential in the situation and neglects the other features or elements which may be irrelevant or non- essential.

7. Law of Response by Analogy:

            According to this law, the individual makes use of old experiences or acquisitions while learning a new situation. The learning of driving a car is facilitated by the earlier acquired skill of driving a motor cycle.

8. The Law of Associative Shifting:

            According to this law, we may get an response, of which a learner is capable, associated with any other situation to which he is sensitive. Thorndike illustrated this by the act of teaching a cat to stand up at a command. A fish was dangled before the cat while he said ‘stand up’. After a number trails by presenting the fish after uttering the command ‘stand up’, he later ousted the fish and the overall command of ‘stand up’ was found sufficient to evoke the response in the cat by standing up or her hind legs.

Educational Implications:

1. Thorndike’s theory emphasizes the importance of motivation in learning. So, learning should be made purposeful and goal directed.

2. It stresses the importance of mental readiness, meaningful practice and incentive in learning process.

3. More and more opportunities should be given to the learners to use and repeat the knowledge they get in the classroom for effectiveness and longer retention.

4. To maintain learned connection for longer period, review of learned material is necessary.

5. The law of effect has called attention to the importance of motivation and reinforcement in learning.

2. Hull’s Drive Reduction Theory of Learning:

  • Drive reduction is a major cause of learning and behavior.
  • Hull suggested that all motivation arises as a result of the need to fulfill certain things.
  • Drive refers to the state of tension caused by biological or physiological needs.

i. Primary Drives (e.g.) hunger, thirst

ii. Secondary Drives (e.g.) money, property.

Drive-Reduction Theory and Human Behavior
Hull's Theory of Learning
Clark L Hull Drive Reduction Theory


  • A rat was placed in a box which was divided into two apartments by a wall with a hole.
  • An electric current was switched on in the compartment, where the rat was.
  • The rat responded in a number of ways.
  • Finally, it jumped into the other apartment through the hole.

Educational Implications:

  • All learning should be as stimulating as possible.
  • Students must be motivated as much as possible.
  • Artificial incentives, drill and practice increase the learning process.

3. Skinner’s Operant Conditioning:

  • It is called as “Instrumental Conditioning” or “Type R – Conditioning”.
  • It refers to ‘a kind of learning process whereby a response is made more probable or more frequent by reinforcement.’
  • “No Stimulus, No Response mechanism” in the evolution of behavior was opposed by B.F.Skinner.
  • Skinner does not believe in stimulus response trigger like behaviour initiating mechanism.
  • In most of our learning situations, our behaviour is shaped and maintained by its consequences.
  • It is operated by the organism itself and maintained by its results.
  • The occurrence of such behaviour was named as ‘operant behaviour’ and the process of learning resulting in such type of behaviour was named as ‘operant conditioning’.
  • Reinforcement must be given only after the desired responses.
  • The learning process can be made by frequent reinforcements.


  • A rat occasionally pressed the bar in a cage and got food.
  • Then the rat repeatedly pressed the bar and got food.
Operant Conditioning (B.F. Skinner) | Simply Psychology
  • A pigeon was put in a cage.
  • Whenever it pecked, food was supplied.
  • Then it started to peck to get the food.

Schedules of Reinforcement

            Imagine a rat in a “Skinner box.” In operant conditioning, if no food pellet is delivered immediately after the lever is pressed then after several attempts the rat stops pressing the lever. The behavior has been extinguished.

            Behaviorists discovered that different patterns (or schedules) of reinforcement had different effects on the speed of learning and extinction. Ferster and Skinner (1957) devised different ways of delivering reinforcement and found that this had effects on

1.The Response Rate – The rate at which the rat pressed the lever (i.e., how hard the rat worked).

2.The Extinction Rate – The rate at which lever pressing dies out (i.e., how soon the rat gave up).

            Skinner found that the type of reinforcement which produces the slowest rate of extinction (i.e., people will go on repeating the behavior for the longest time without reinforcement) is variable-ratio reinforcement. The type of reinforcement which has the quickest rate of extinction is continuous reinforcement.

(A)       Continuous Reinforcement

            An animal/human is positively reinforced every time a specific behavior occurs, e.g., every time a lever is pressed a pellet is delivered, and then food delivery is shut off.

  • Response rate is SLOW
  • Extinction rate is FAST

(B)       Fixed Ratio Reinforcement

            Behavior is reinforced only after the behavior occurs a specified number of times. e.g., one reinforcement is given after every so many correct responses, e.g., after every 5th response. For example, a child receives a star for every five words spelled correctly.

  • Response rate is FAST
  • Extinction rate is MEDIUM

(C)       Fixed Interval Reinforcement

            One reinforcement is given after a fixed time interval providing at least one correct response has been made. An example is being paid by the hour. Another example would be every 15 minutes (half hour, hour, etc.) a pellet is delivered (providing at least one lever press has been made) then food delivery is shut off.

  • Response rate is MEDIUM
  • Extinction rate is MEDIUM

(D)       Variable Ratio Reinforcement

Behavior is reinforced after an unpredictable number of times. For examples gambling or fishing.

  • Response rate is FAST
  • Extinction rate is SLOW (very hard to extinguish because of unpredictability)

(E)       Variable Interval Reinforcement

Providing one correct response has been made, reinforcement is given after an unpredictable amount of time has passed, e.g., on average every 5 minutes. An example is a self-employed person being paid at unpredictable times.

  • Response rate is FAST
  • Extinction rate is SLOW

Educational Implication:

  • Programmed Learning, Teaching Machines, Computer Assisted Instruction are based on Skinner’s theory.

Cognitive Theories:

  • It is called as Field Theories, or Gestalt Theories or Learning by Insight.
  • It emphasizes on internal mental processes like perception, attitude, insight etc.
  • “Gestalt” is the German word which means “Whole” or Pattern or Configuration”.
  • The chief exponents are Max Wertheimer, Kohler and Koffka.
  • Max Wertheimer was the founder of Gestalt psychology.
  • Learning process can be done by insight, introspection and understanding.

1. Kohler’s Gestalt Theory of Insight Learning

2. Lewin’s Field Theory of Learning

3. Tolman’s Sign Theory of Learning

1. Kohler’s Gestalt Theory of Insight Learning:

  • It is called as “Learning by whole or learning by insight”.
  • It concerned with the nature of perception.
  • An individual learner perceives whole not parts.
  • There are 4 steps in insightful learning.

i. Preparation

ii. Incubation

iii. Insight or illumination

iv. Evaluation


  • The chimpanzee (Sulthan) joined the two sticks together and reached the banana.
  • The chimpanzee placed one box over the other to get banana.

Educational implications:

  • Subject matter should be presented in whole form. (e.g.) Plant
  • Problem-solving approach should be followed in teaching.

2. Lewin’s Field Theory Learning:

  • Kurt Lewin emphasized the study of behavior as a function of the total physical and social situation.
  • He favoured an “idiographic psychology” in which the focus was on the individual.
  • He described his viewpoint in the following formula:
    • B = F (PE)
    • B – Behaviour
    • F – Function
    • P – Person
    • E – Environment
  • He explained an individual’s behavior on the basis of his life space.
  • An individual’s life space includes the person, his drives, tensions and his environment.
  • It refers total psychological world in which a person lives at a certain time.
  • Lewin’s Theory is based on concepts like topology and Vector Analysis.
Kurt Lewin's Field Theory

The main concepts used in Lewin’s field theory are as follows:

1. Topology:

            It is also called topological. Two basic concepts which topological space denotes are:

(i) Connectedness, and

(ii) Part-whole relationships.

            Topological concepts are used to represent the structure of life- space in such a way as to define the range of possible perceptions and actions. This is accomplished by showing the arrangements of the functional parts of life-space. The parts are shown as various regions and their boundaries. When an individual structures his life-space, he divides it into regions.

2. Vector:

            The term vector represents a force which is influencing movement towards a goal or away from it. If there is only one vector (force), there is movement in the direction of the vector. However, if there are two or more vectors acting simultaneously in different directions, the movement is in the direction of the resultant force.

3. Life-Space:

            It is also called the psychological field. The psychological field is the space in which the person moves psychologically. It contains the whole of one’s psychological reality – one’s self and what one thinks of or what one gains from one’s physical and social environment.

4. The Person in Life-Space:

            The person is often represented as a point moving about in his life-space, affected by pulls and pushes upon him, circumventing barriers in his locomotion in his own life-space.

5. Valence:

            When a person is attracted by an object, that object is said to have a positive valence. When a person is repelled by an object that is said to have a negative valence. The person tends to move towards a region in life- space that has positive valence and he tends to move away from a region in life-space that has negative valence. Because life-space may contain regions with several valences active at a time, these give rise to conflict, especially when the opposing forces are approximately in balance. Lewin specifies three chief kinds of conflict:

(1) Two Positive Valence: Such as when a child has to choose between going to picnic and playing with his friends.

(2) A Simultaneous Positive and Negative Valence: Such as when a child is offered for a reward for the school task he does not wish to perform.

(3) Two Negative Valence: Such as when a child is threat-end with punishment if he does not do a task which he does not wish to perform.

6. Distance and Direction:

            When there is a close correspondence between life-space and physical space, physical distances and directions may be used for experimental purposes as approximations of distances and directions in life space.

7. Behaviour:

            Lewin regards behaviour as a function of present life space. He insists that behaviour depends upon the present and not upon the past or future.

8. Barrier:

            It is a dynamic part of an environment which resists motion through it. It stands in the way of a person’s reaching his goal.

9. Goal:

            Goal is a region of valence-region of life-space to which a person is psychologically attracted.

10. Tension:

            It is very closely to and is descriptive of psychological needs. Release of tension may be achieved either through reaching a goal or through reconstructing a life-space.

11. Cognitive Structure:

            It is an environment including a person as known by the person. It is synonymous with insight or understanding.

3. Tolman’s Sign Theory of Learning:

  • Behaviour can be modified by experience and training.
  • This theory is called as “Sign Significance Theory, Expectancy Theory, Purposive Behaviourism or Sign Theory”.
  • Behaviour is goal-directed i.e it is purposive.
  • Learning is based upon some signs or clues leading to the goal.
  • The learner learns not the movement patterns, but the sign-significant relations.    

Laws of Learning:

            Tolman stated the following laws of learning:

1. Law of Capacity:

            This relates to traits, characteristics and aptitudes of the learner which determine type of tasks and situations which can be mastered successfully.

2. Law of Stimulus:

            It deals with conditions inherent in the material itself such as belongingness of its parts and how successfully it leads to insightful solution.

3. Law of Manner:

            It is concerned with the manner of presentation of material such as frequency of presentation, distribution of practice and use of rewards.

Robert Gagne’s Theory of Hierarchical Learning:

  1. Signal Learning:
  2. The individual learns to make a general response to a signal. (e.g.) Pavlov’s Classical Conditioning.
  3. S-R Learning:
  4. The learner acquires a response to a stimulus. (e.g.) Skinner’s Operant Conditioning.
  5. Chaining:
  6. The learner develops the ability to connect two or more previously learned stimulus response connections. (e.g.) Riding a bicycle.
  7. Verbal Associations:
  8. It refers to the links between the items which are verbal in nature. (e.g.) Language learning.
  9.  Discrimination Learning:
  10. It involves developing the ability to make appropriate responses to a series of similar stimuli.
  11.  Concept Learning:
  12. The learner learns to give a common response to a class of stimuli that have common attributes.
  13.  Rule Learning:
  14. The learner learns relationships between concepts and apply these relationships in different situations.
  15.  Problem Solving:
  16. This is the highest level of cognitive process. It is the ability to solve the problem.

Albert Bandura’s Theory of Social Learning:

  • Human behaviour is learned through observation and modeling.
  • People learn new information and behaviours by watching other people.
  • The children learn and imitate behaviours what they observe in other people.

(e.g.) Bandura’s experiment of Bobo Doll experiment.


  1. Attention: 
  2. Pay attention to a particular behaviour.
  3. Retention:
  4. The ability to retain or store information.
  5. Reproduction:
  6. It is to perform the behaviour what one has observed.
  7. Motivation:
  8. The behaviour of the model imitated by the learner is to be reinforced for proper adaptation and further continuation.  (e.g.) T.V. Programme on new dish.

Information Processing:

            Information processing refers to the ways people handle stimuli from the environment, organize data, sense problems, generate concepts and solutions to problems and employ verbal and non-verbal symbols.

Three Stage Information Processing Theory:

  • It was propagated by Atkinson and Shiffrin.
  • Learning is the outcome of the processing of the information carried out by human brain at three stages.

(1) Sensory Registry:

            The process of learning or memorization starts with the interaction of one’s sense organs with one’s environment.

(2) Short Term Memory:

            The information is processed by the brain for its proper interpretation, assimilation and responding. It is one’s working memory.

            (3) Long Term Memory:

                        It is process of storing sensory information on the permanent memory.

Miller’s Information Processing Theory:

  • Information processing helps in acquiring new experiences and learning new ways of behaving.
  • Students learn better, while they are processing, storing and retrieving information.
  • Information processing helps the students to build desirable cognitive structures.
  • Successful encoding is essential for the proper processing of the received sensory information.
  • “Chunking” refers to the meaningful Organization of the subject matter at cognitive structure.


  1. Encoding:
  2. It refers to ‘gathering and representing information.
  3. Retention:
  4. It refers to ‘holding information in the mind’.
  5. Retrieval:
  6. It refers to getting at the information when needed.

Dual Coding Theory of Information Processing:

  • It was proposed by A. Paivio.
  • It attempts to provide equal weightage to verbal and non-verbal information processing in the task of learning.
  • There two cognitive subsystems namely ‘imagery’ and ‘logogens’.
  • ‘Imagery’ is the representation of non-verbal objects.
  • ‘Logogens’ deals with verbal entities.

Experiential Learning:

  • It was propagated by Carl Rogers.
  • As a humanist, he believed in the strengths and potentialities of human beings.
  • He emphasizes on the application of knowledge in different situations.
  • Experiential Learning is called as ‘learner centered approach’.

Maslow’s Humanistic Theory of Learning:

  • Maslow coined the term ‘the third force’ to describe the humanistic approach.
  • It paved the way for the reaffirmation of the affective and subjective world by providing place for personal freedom, individual choices, motivation and feelings.
  • Humanistic Theory of Learning owes its origin to Maslow’s concept of hierarchy of needs.
  • The appearance of one need generally depends on the satisfaction of the others.
  • They are closely related to each other and may be arranged from the lowest to the highest development of the personality.
  • Learning process helps an individual become true to himself by developing him according to his own nature. 

Learning Curve:

  • A learning curve is a concept that graphically depicts the relationship between the cost and output over a defined period of time.
  • It was first described by Hermann Ebbinghaus in 1885.

There are 4 types of learning curves:

1. Diminishing-returns Learning Curve: 

            In this type of learning, the “rate of increase” in the degree of skill is higher in the beginning but decreases with time until it reaches zero and the person has obtained the maximum skill. It indicates that initially there is a spurt in learning, usually the graph levels at some stage indicating the maximum performance achieved. This is because at the beginning of the learning process, the learner is highly motivated to exhibit a significant surge of effort.

Diminishing Return Learning Curve

2. Increasing Returns Learning Curve: 

            Another type of learning curve is the “increasing-return curve ” which is just the opposite of “diminishing-return curve” in the sense that there are certain learning skills where the rate of increased learning is slow in the beginning and then it increases until the maximum potential for learning is reached. This usually occurs when a person is learning a complex unfamiliar and new task.

Increasing-Return Learning Curve

3. Increasing-Decreasing-Return Learning Curve: 

            It is a combination both the “diminishing-returns curve” and the “increasing-returns curve”. It is an “s-Shaped curve”. If a person is totally new to the skill that he is learning, then all learning will probably follow an S-shaped curve. The lower portion of the curve represent the initial stages of acquiring a skill with very slow learning initially followed by successively greater returns, eventually reaching the absolute limit.

Increasing-Decreasing Return Learning Curve

4. Increasing -Decreasing-Return Leaning Curve (complex pattern)

  • Slow Learning: The initial stage in the above curve is that of slow learning because of the newness and difficulty of skill. Once the learner has acquired some basics of his operations, he gains some confidence and this results in the second stage of increasing returns.
  • Increasing Returns: The learner gains confidence in this stage. He has acquired the required skill. This results in the third stage.
  • Plateau: When the learner feels that he has acquired the required skills, he reaches a comparative plateau where no further gains in skills are acquired. However, this may be a false plateau and the learner may be developing new ideas in improving efficiency.
  • Peak Proficiency: The development and application of new ideas may further improve upon his skill until he reaches the peak inefficiency, beyond which the skill becomes a kind of habit and an integral part of operations.
  • Over Learning: When the skill becomes a kind of habit, the period is termed as over learning because the learning becomes automatic and unforgettable.

Transfer of Learning:


  • The application of knowledge and skills learned from one situation to another situation.

Types: (3)

  1. Positive Transfer:
    1. When a task previously learned helps in learning a new task is known as positive transfer. (e.g.) Learning of cycle riding helps in bike riding.
  • Negative Transfer:
    • When a task previously learned obstructs in learning a new task is known as Negative Transfer. (e.g.) Learning mother tongue obstructs the learning of English.
  • Zero Transfer:
    • When a task previously learned neither helps nor obstructs is known as Zero Transfer. (e.g.) Learning of Maths doesn’t affect the learning of music.

Theories of Transfer of Learning:

  1. Theory of Mental Discipline: or Faculty Theory:
    1. It was propounded by Thorndike.
    1. This theory was challenged by William James.
    1. It believes that the mind is composed of many independent faculties like memory, attention, imagination, reasoning and judgement etc.
    1. These faculties are the muscles of the mind and they can be strengthened or improved through exercise.
    1. The learner’s mind is strengthened through the memorization and it can be useful in many situations.
  • Theory of Identical Elements or Components:
    • It was propounded by Thorndike.
    • It was supported by Woodworth.
    • Transfer of learning happens when there are common or identical elements in both situations. (e.g.) Maths helps to learn physics.
  • Theory of Generalization of Experience:
    • It was propounded by Charles Judd.
    • The learner reaches a conclusion or generalization by an experience.
    • The generalization can be applied in new situations.
  • Theory of Ideals:
    • It was propounded by W.C. Bagley.
    • The ideals like love, tolerance, discipline, respect can be transferable from situation to another situation.

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