Testing & Indiv Differences

Intelligence the ability to learn from experience, think

rationally, and adapt to changes in the environment

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12 interesting facts about IQ

1. IQ is associated w/ some simple abilities

2. School attendance correlates w/ IQ

3. IQ is not influenced by birth order.

4. IQ is related to breast feeding

5. IQ varies by birthdate.

6. IQ evens out with age.

7. Intelligence is plural, not singular.

8. IQ is correlated w/ head size.

9. Intelligence scores are predictive of real world outcomes.

10. Intelligence depends on context.

11. IQ is going up.

12. IQ may be influenced by school caféteria menu.

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11-1 Intel Objectives

1.  Trace the origins of intelligence testing, and describe the Stern formula for the intelligence quotient.

2.  Discuss whether intel should be considered a general  mental ability or many specific abilities.

3.  Identify the factors associated with creativity, and describe the relationship between creativity and intelligence.

4.  Describe efforts to correlate intelligence with brain anatomy, brain functioning, and cognitive processing speed

5.  Distinguish between aptitude and achievement tests, and describe modern tests of mental abilities such as the WAIS.

6.  Describe test standardization, and explain the importance of appropriate standardization samples for effectively interpreting intelligence test scores.

7.  Distinguish between the reliability and validity of intelligence tests, and explain how reliability and validity are assessed.

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Origins of Intelligence Testing

What is Intel? the ability to learn from experience, think 

rationally, and adapt to changes in the environment 

Alfred Binet around 1900 French gov. made a law 

saying all children must attend school all kids were not on the same level  Binet’s job was to fig out who needed 

special help Dev test to meas mental age -intellectual level in years that a child is 

functioning on 

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Origins of Intelligence Testing

Mental Age

child who does as well as the average 8-year-old is said to have a mental age of 8

Lewis Terman  Stanford prof who Revised Binet’s test for Calif 

schoolchidren & renamed it the Stanford-Binet IQ Test which gave kids an Intelligence Quotient

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Origins of Intelligence Testing

IQ = mental age (MA) X 100 Chronological age (CA) Was dev by William Stern therefore, average intelligence should be 100 formula works well for children, but not adults Today’s tests produce a mental ability score based on the test-takers 

performance vs. the average performance of others of the same age 50% of pop. score between 90-110 67% of pop. score between 85-115 

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Origins of Intelligence Testing

Terman was a supporter of the eugenics movement [influenced by Francis Galton’s Hereditary Genius (1869) (Galton is Darwin’s Cousin)]

movement that proposed measuring human traits and using the result to encourage or discourage people from reproducing

in its pure form, eugenics was supposed to reduce crime and homelessness

but it ended up being a tool of racism instead US government tested immigrants when looking for recruits for WWI led to 1924 immigration law greatly limiting immigrants from Southern and 

Eastern Europe 

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What is Intelligence?

What is Intelligence? -def. Of intelligence is a socially constructed concept -the word means different things in different cultures -usually involves characteristics that make people successful in 

those cultures  We must be careful not to reify IQ Scores >>Reification: seeing an abstract, material concept as something concrete – it’s 

just a score on a test, not something concrete that someone has ***a major debate among psychologists*** Is intelligence a single overall ability or several specific abilities? 

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What is Intelligence?

Charles Spearman believed that there was a general intelligence or “g” -this g factor underlies all specific factors

Evidence: people who score high in one specific area also score high in others.

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What is Intelligence? A. Factor-Analysis -a statistical procedure that identifies clusters of related items on a 

test that measure a common ability -used to find out whether there might be a general ability factor that 

runs throughout our specific mental abilities  Spearman’s 2 Factor Theory of theory intelligence -Spearman helped develop factor-analysis to support g factor theory -said intelligence was made up of 2 factors g factor – general ability s factor – specific ability 

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Are There Multiple Intelligences? g factor underlies the specific abilities -said people who score high on one s factor usually do well on others as well -he attributed this to the g factor 

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What is Intelligence? - Thurstone

Thurstone’s Theory of Primary Mental Abilitiesidentified 8 factors that make up intelligence

1)visual-spatial ability 2)perceptual speed 3)numerical ability 4)verbal meaning 5)memory 6)word fluency 7)deductive reasoning 8)inductive reasoning said it is possible to be very high in one factor and

low in another

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What is Intelligence? – Broadened Theories: GardnerGardner’s Theory of Multiple Intelligences

said there are 8 different types of intelligence 1)linguistic any famous writer 2)logical-mathematical Einstein 3)visual-spatial Picasso 4)body-kinesthetic Jordan/ Surgeon/ ballerina 5)musical-rhythmic any great composer 6)interpersonal Gandhi 7)intrapersonal Freud 8)Nature Darwin

thought each intelligence was based in different parts of the brain & each intelligence varies in intensity in every person

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What is Intelligence? – Broadened Theories: Sternberg

Sternberg’s Triarchic Theory of Intelligence-said there are 3 aspects of intelligence1)analytical intelligence

-academic problem solving skills2)creative intelligence-being able to adapt quickly to new situations and come up with original 

ideas3)practical intelligence

-everyday tasks *Said Trad tests test 1 but not 2&3 which are better predictors of 

vocational success

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What is Intelligence? – Broadened Theories: Emo Intel

Emotional Intelligence (Daniel Goleman) interested in finding out why very intelligent people aren’t always 

successful in life listed 5 areas needed for life success 1)self-awareness 2)self-motivation 3)impulse control 4)mood management 5)people skills

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FYI: Creativity’s Relnshp w/ Intel

Creativity – ability to produce novel & valuable ideas Intrinsically motivated

Intelligence and Creativity Pos Correlated Through IQ of 120 (relnshp wkns beyond 120)

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Biological Correlates

2 Correlates:  Brain Size, Processing Speed (Perceptual Speed & Neurological Speed)

1. Brain Size  Early 1800s Franz Gall and his school of phrenology believed that 

they could tell your intelligence and other characteristics about you by the size and shape of your skull

modern studies do show a slight correlation (+.15) b/w head size (relative to body size) and intelligence

however, there is more inside your skull than just the brain newer studies using MRI technology to measure actual brain size 

reveal a correlation of +.44 

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Biological Correlates

Interesting Info: Einstein’s brain was 15% larger than average in the parietal lobes lower region (math and spatial information processing located here)

-other areas of his brain were smaller than average-may indicate why he was so slow in learning to speak 

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Biological Correlates

2. Processing Speed positively correlated with Intel

Diff b/w Sink & Wink ‘quick wits’ higher verbal ability scores

-PET scans have revealed that high IQ performers use less glucose when completing cog. tasks than do average people 

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Biological Correlates

2 cont’d. Processing Speed :Perceptual Speed

+.4 correlation b/w quick perceptual speed and intelligence 

People who can perceive the stimulus very quickly tend to score somewhat higher on intelligence tests

Stimulus Mask

Question: Long side on left or right?

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Biological Correlates

2. Cont’d Processing Speed : Neurological Speed -Pushing a button when an X Appears on a Screen

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Assessing Intelligence

Aptitude tests- predict your ability to learn a new skill

Achievement tests- intend to reflect what you have learned

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Assessing Intelligence

the most widely used intelligence test today is the Wechsler Adult Intelligence Scale (WAIS)

test consists of 11 subtests Thought trad intel tests were biased for native Eng spkrs so he 

created a nonverbal, performance section gives an overall score, but also givesseparate verbal and performance scores if your verbal score is vastly different than your performance 

score it may indicate a learning problem -Figure 11.2 on page 433 7th ed or 436 8th ed lists examples of 

the 11 subtests

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Assessing Intelligence: Sample Items from the WAIS

From Thorndike and Hagen, 1977

VERBAL

General Information Similarities Arithmetic ReasoningVocabularyComprehensionDigit Span

PERFORMANCE

Picture Completion Picture ArrangementBlock DesignObject AssemblyDigit-Symbol Substitution

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Assessing Intelligence

Standardization- process of defining meaningful scores relative to a pretested group

-basically setting a baseline -if the test is standardized it should result in a normal distribution 

(and a normal curve) Normal Curve 

the symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes

most scores fall near the average, and fewer and fewer scores lie near the extremes

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The Normal Curve11-1

Assessing Intelligence

mean score is 100 on IQ test 50% of pop. 90-110 68% of pop. 85-115 96% of pop. 70-130 2% < 70 mental

retardation 2% > 130 gifted

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Getting Smarter?- “ The Flynn Effect” - IQ Scores Raise 20 pts per gen… why??

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Assessing Intelligence

Good Tests are Reliable and Valid

Reliability~Consistency

1).  Test-retest reliability-researchers give participants the same test or another form of it and 

compare the scores-the higher the correlation b/w scores the higher the reliability2).  Split-half scores-split the test in half and see if odd question scores are consistent 

with even question scores-Stanford-Binet and WAIS both have about +.9 reliability 

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Assessing Intelligence

Reliability Cont’d3. Equivalent-Form Reliabilty4. Test-Retest Reliability

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Assessing Intelligence

Validity~ Accuracy --extent to which the test measures what it is supposed to be measuring

1. content validity-extent to which a test samples the behavior of interest

ex.  Road test for a driver’s license2. predictive validity- the success with which a test predicts 

the behavior it is designed to predict assessed by computing the correlation between test 

scores and the criterion behavior also called criterion-related validity

ex.  An aptitude test for a job How well the SAT predicts college performanceFyi-SAT has a +.5 correlation w/ undergrad GPA (freshman yr)

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Assessing Intelligence

As the range of data under consideration narrows, its predictive power diminishes

Greater correlationover broad rangeof body weights

10

9

8

7

6

5

4

3

2

1

0

Little corre-lation withinrestricted

range

Football linemen’s

success

Body weight in pounds180 250 290

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8. Distinguish between the reliability and validity of intelligence tests, and explain how reliability and validity are assessed.

9. Discuss evidence for both genetic and environmental influences on intelligence.

10. Describe group differences in intelligence test scores, and show how they can be explained in terms of environmental factors.

11. Discuss whether intelligence tests are culturally biased.

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Assessing Intelligence

Can a test have high reliability but low validity? Yes Can a test have low reliability but high predictive 

validity? No Could have content validity if it is measuring what its 

supposed to See Barron’s Manual for more in depth on Reliability 

& Validity if needed

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Stability v. Change

2-7 mo old who habituates (grows bored w/ picture – stares at it for shorter pd of time) faster scores higher IQ @ 11

Early reading better predictor of Intel than talking (Einstein)

By age 4, intel tests predict adolescent & adult scores After age 7 IQ scores stabilize 11 yr old – 77 yr old (+.73 correlation) SAT-GRE (+.86 correlation)

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Extremes of Intel

MR (Mental Retardation) 1% of pop below 70 & can’t live indep (there are 2% total below 70) physical cause sometimes Down Syndrome (extra chrom) FAS--Leading known cause of MRGifted Can be isoloated/introverted/ in own world Eg. Piaget studied birds/ fossils 

@ 7 and pub scient art @15 However, most gifted thrive sociallyTracking (Academic) Doesn’t help Hi IQ kids, hurts low IQ kids (self-fulfilling prophecy)>>why there is no A.T. in Jap & China in elem sch

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Other Tests

Personality TestsMMPI Minnesota Multiphasic Personality InventoryMyers-Briggs Personality Inventory

Projective Tests- Used by Psychoanalysts to Tap Unconscious

1. TAT2. Rorschach Inkblot>>personality slides

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The Dynamics of Intelligence

Mental Retardation a condition of limited mental ability indicated by an intelligence score below 70 produces difficulty in adapting to the demands of life varies from mild to profound FAS is leading known cause of MR

Down Syndrome retardation and associated physical disorders caused by 

an extra chromosome in one’s genetic makeup

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The Dynamics of Intelligence

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Genetic Influences

The most genetically similar people have the most similar scores

Also:  Higher correlation than siblings reared together shows environmental (nurture) inf

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Genetic Influences

Heritability the proportion of variation among individuals that we can 

attribute to genes Doesn’t pertain to indiv but as to why 2 indivs or groups 

differ Boys in barrel example – heritability of intel 100% (diff is 

100% attributable to genes)

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Genetic Influences11-2

Environmental Influences

Extra Early Childhood instruction doesn’t produce extra intellectual dev over a normal env <<but>> a subnormal env can produce cog delays

>>Head Start Program Intel inc during school year and dec during summer Flynn Effect – results from more people aware of this info

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Environmental Influences

The Schooling Effect

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Ethnic Similarities and Differences

Bell curve for whites is centered around 100, for blacks: 85 Flynn Effect: 20 pts smarter than last generation To what do we attribute F.E (generational gap)? To what do we attribute racial gap?Facts: Indiv diff w/in races > than those b/w races Group differences provide little basis for judging individuals (women 

outlive men by six years but knowing an individual’s gender doesn’t tell you how long they’ll live.)

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Group Differences

Group differences and environmental impact

Variation within group

Variation within group

Difference within group

Poor soil Fertile soil

Seeds

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Gender Differences

Males=Females as group on math test mean scores F higher on computation, M on prob solving(Int fact: males have a gr8er differentiation w/in group) Differences can be explained in socialization differences b/w males & 

females Males better on spatial tasks (evol per: hunting in 3D space, bio per: 

prenatal male sex hormones) Females better on emotion detecting (evol per: women’s ability to det 

emotions helped them read emo in infants & potential lovers)

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Group Differences

Sample Test of Spatial Abilities: The Mental Rotation Test 

Which two of the other circles contain a configuration of blocksidentical to the one in the circle at the left?

Standard Responses

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Group Differences

Stereotype Threat A self-confirming concern that one will be evaluated based on a 

negative stereotype~”self-fulfilling prophecy”

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