Mental Age × 100 - Tata Interactive Learning Forum

•••••••••••••••••••••••••••••••••• Vanessa D’silva Clinical Psychologist, Learning Disability Clinic, KEM Hospital

What Is Intelligence? 

Ability to adjust to different situations.

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Ability to learn.

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Ability to engage in abstract thinking.

Definition By Wechsler

“The aggregate or global capacity of the individual to act purposefully, think rationally and deal effectively with the environment.”

Definition

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Aggregate and Global implies it is revealed by an individual behaviour as a whole. Purposeful implies that intelligent behaviour is goal directed which is based on drives and incentives.

Theories Of Intelligence

Spearman’s ‘g’ Factor Theory

Thurston’s Group Factor Theory

Thorndike’s Multifactor Theory

Spearman’s ‘g’ Factor • All mental activity have the ‘g’ factor or the mental ability.

• All individuals possess this, but in varying degrees. • The distinguishing feature of all mental tasks that are high in ‘g’ is the ability to form abstract linkages between apparently different things.

Spearmen’s ‘g’ Factor Theory 

Spearmen arrived at the concepts based on inter correlations between different tests he administered to his subjects. These were as follows:  Analogies.  Completion.  Understanding  Opposites.  Instructions.

 Resemblances.  Inferences.

Paragraphs.

Spearmen’s ‘g’ Factor Theory   

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r = .55 Analogies and Opposites. r = .32 Instructions and Resemblances. However, the correlations were not perfect positive correlations. This led Spearman to postulate the existence of ‘s’ (specific) factors. A specific factor is one that is characteristic of a single mental task and is unique from other mental tasks.

Thorndike’s Multifactor Theory 

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Intelligence is composed of a multitude of highly specific factors. Two mental tasks will be highly correlated if they shared these minute elements. Thus Thorndike implicitly accepts the existence of group factors.

Thorndike’s Multifactor Theory 

Thorndike developed the CAVD test i.e. C

– Sentence Completion.  A – Arithmetic Reasoning.  V – Vocabulary.  D – Following Directions. 

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Each of the subtests measured different aspects of Abstract Intelligence. Significant positive correlations were found between subtests thus indirectly giving the ‘g’ factor.

Thurston’s Group Factor Theory 

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According to Thurston mental action have in common primary factors or group factors. These primary factors are shared by some mental tasks and not others. They serve to bind mental activities into separate groups and they are relatively pure in nature.

Thorndike’s Multifactor Theory 

He administered the following tests (Primary Mental Abilities Test): N – Number Fluency.  W – Word Fluency.  V – Verbal Comprehension.  S – Spatial.  M – Memory.  R – Reasoning.  P – Perceptual Speed. 

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However, inter correlations were significant high positive ones. This led Thurston to propose the existence of a second order ‘g’ factor.

Conclusion 

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All three theories ultimately arrive at considerable agreement with each other. Critics of such theories believe there no real difference between ‘general’, ‘group’ and ‘specific’ factors. These differences emerge simply because of the number and nature of tests on which a factor analysis is conducted.

DSM –IV TR Classification 

IQ 71-84 

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IQ 50 -55 to approx. 70 

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Moderate Mental Retardation.

IQ 20-25 to approx. 35-40 

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Mild Mental Retardation.

IQ 35-40 to approx. 50-55 

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Borderline Intellectual Functioning.

Severe Mental Retardation.

IQ Below20-25 

Profound Mental Retardation.

Wechsler’s IQ Classification 

IQ 90 – 110 

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IQ 110-120 

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Above Average Intelligence.

IQ 120-130 

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Average Intelligence.

Superior Intelligence.

IQ 130 and above 

Very Superior Intelligence.

Salient Features Of IQ Tests      

Standardized instructions for test administration. Time limit allotted to each items. The item limit after which test is to be discontinued. Evaluative criteria together with specimen answers. Scheme of scoring. Bonus scores to be given for rapid performance.

Wechsler’s Intelligence Scale For Children By Dr M. Bhatt 

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This scale includes 12 separate subtests. Age 5+ to15+ It yields Verbal IQ, Performance IQ and Full Scale IQ.

Verbal Tests • Information • General Comprehension • Arithmetic • Similarities • Vocabulary • Digit Span

Performance Subtests • • • • • •

Picture Completion Picture Arrangement Block Design Object Assembly Coding Mazes

WISC Scoring 

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Raw scores obtained for each subtest are converted to Scaled Scores. Scaled Scores are converted to Verbal IQ and Performance IQ. The sum of Verbal IQ and Performance IQ Scaled Scores give the corresponding Full Scale IQ.

LD Features On The WISC 

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The difference between Verbal IQ and Performance IQ is 15 or greater it indicates presence of extraneous factors.

Resulting Full Scale IQ obtained is considered not a true indicator of intelligence. Scores on the ACID profile lower than intra test average i.e. the scores on Arithmetic, Information, Coding and Digit Span.

WAIS-R Block Design Task

Seguin Form Board (SFB) 

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Aim: The individual has to insert geometrical shaped blocks into corresponding recesses as quickly as possible. Norms available from 3years to 20 years. Used particularly for young children and supplemented with other tests. Advantages:  Spontaneous

arousal in children.  Amenable & brief.  Valid ‘g’ obtained.

Kamat Binet Test Of Intelligence (KBI) 

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The original test was the Stanford Binet scales. This test was developed based on the concept of age norm. Kamat undertook a revision of the Stanford Binet Scales to suit Indian conditions. The tests has subtests from Age III to XXII.

Administering The KBI 

Begin with the tests of the year of the child.

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He/ She may pass on some but fail in few.

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Work upwards till the child fails on all items.

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Then work below the child’s chronological age until all items are passed.

Scoring And Interpreting The KBI 

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For each item passed the child earns a credit of 2 months, 4 months or 6 months depending on the corresponding age. IQ = Mental Age × 100 Chronological Age The IQ thus obtained is classified.

Raven’s Progressive Matrices

Raven’s Progressive Matrices  

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It is a test of observation and clear thinking. Measures ability to form perceptual relations, reason by analogy independent of language and formal schooling. It consists of 5 sets of 12 items each. Each item contains a figure with a missing piece. Norms are available for age 6 – 16.

Questions?

•••••••••••••••••••••••••••••••••• Vanessa D’silva Clinical Psychologist, Learning Disability Clinic, KEM Hospital