Chapter 11 pt. 2: Chapter 11 pt. 2: Intelligence AssessmentIntelligence Assessment

Qualities of A Good TestQualities of A Good Test

To be accepted all To be accepted all psychological tests must be:psychological tests must be:

1.1. StandardizedStandardized

2.2. Reliable Reliable

3.3. ValidValid

StandardizationStandardizationStandardization:Standardization: is a two part test is a two part test

development procedure that first development procedure that first establishes establishes test normstest norms by testing a by testing a representative sample of individuals representative sample of individuals who initially took the test, then who initially took the test, then assures the test is administered and assures the test is administered and scored correctly for all administrators.scored correctly for all administrators. Your scores are compared with the pretested Your scores are compared with the pretested

group scores (norms) who took the test. group scores (norms) who took the test. Standardized tests usually follow a normal Standardized tests usually follow a normal

distribution.distribution.

Standardized Tests Usually Follow Standardized Tests Usually Follow a Normal or Bell Curved a Normal or Bell Curved

Distribution Where Most Scores Distribution Where Most Scores Occur in the Middle.Occur in the Middle.

Ninety-five percent of all people fall within 30 points

of 100

Number of

scores

55 70 85 100 115 130 145

Wechsler intelligence score

Sixty-eight percentof people score within 15 points

above or below 100

Understanding Distributions: Understanding Distributions: Variance and Standard Variance and Standard

DeviationDeviation Both variance and standard Both variance and standard deviation are measures which tell deviation are measures which tell us how scores differ from one us how scores differ from one another or how spread out the another or how spread out the distribution is.distribution is.

Variance is reported in squared Variance is reported in squared units.units.

To get the standard deviation To get the standard deviation which will be in regular units you which will be in regular units you just take the square root of the just take the square root of the variance.variance.

Reliability vs. Validity (DON’T MIX Reliability vs. Validity (DON’T MIX THEM UP)THEM UP)

ReliabilityReliability deals with consistency. deals with consistency.

Asks the question Asks the question do I always get do I always get SIMILAR results each time the SIMILAR results each time the test is administered?test is administered?

QUESTION: Would basing QUESTION: Would basing intelligence on a man’s arm pit hair intelligence on a man’s arm pit hair color be a reliable measure? Why or color be a reliable measure? Why or Why Not? Why Not?

Classic Examples of Ways to Classic Examples of Ways to Check Reliability (Consistency)Check Reliability (Consistency)

1. 1. Test/Retest:Test/Retest: same test is same test is administered to the same group on two administered to the same group on two different occasions and compared. different occasions and compared.

2. 2. Split half:Split half: score on one half of test score on one half of test questions is correlated with the score on questions is correlated with the score on the other half to see if they are consistent. the other half to see if they are consistent.

3. 3. Alternate form (Equivalent Form):Alternate form (Equivalent Form): two different versions of a test on the same two different versions of a test on the same material are given to the same test takers, material are given to the same test takers, and the scores are correlated to see if and the scores are correlated to see if results are consistentresults are consistent. .

Reliability vs. Validity (DON’T Reliability vs. Validity (DON’T MIX THEM UP!)MIX THEM UP!)

ValidityValidity deals with accuracy or deals with accuracy or predictability. predictability.

Asks the question Asks the question does the test does the test measure what it is supposed measure what it is supposed to measure?to measure?

Would using a scale that assessed Would using a scale that assessed athletic ability by measuring athletic ability by measuring fingernail length be a valid measure? fingernail length be a valid measure? Why or Why Not? Why or Why Not?

Types of ValidityTypes of Validity1. Content or Face Validity:1. Content or Face Validity: is a is a

measure of the extent to which the measure of the extent to which the content of the test measures all of the content of the test measures all of the knowledge or skills that are supposed to knowledge or skills that are supposed to be included within the domain being be included within the domain being tested?tested?Example: If 45% of the Chapter 11 AP Psych Example: If 45% of the Chapter 11 AP Psych

Exam asks you to solve calculus problems it Exam asks you to solve calculus problems it lacks content or face validity. lacks content or face validity.

2. Predictive Validity:2. Predictive Validity: The success The success with which a test predicts the behavior it with which a test predicts the behavior it is supposed to predict.is supposed to predict.Do high SAT scores correlate with high Do high SAT scores correlate with high

college grades?college grades?

Types of ValidityTypes of Validity3. 3. Construct Validity:Construct Validity: refers to refers to

whether or not a scale measures the whether or not a scale measures the theorized concept (or construct) it is theorized concept (or construct) it is supposed to. supposed to.

If an IQ test has construct validity, it If an IQ test has construct validity, it would mean the problems truly deal would mean the problems truly deal with all the components that make a with all the components that make a person intelligent. (Intelligence would person intelligent. (Intelligence would be the construct). be the construct).

Predictive Validity is Based on Predictive Validity is Based on CriterionCriterion

Criterion:Criterion: the behavior that a the behavior that a test is supposed to predict. Is test is supposed to predict. Is used to see if test is successful. used to see if test is successful.

What would the criterion be for What would the criterion be for the SAT’s? the SAT’s?

What would the criterion be for What would the criterion be for the NFL combine drills?the NFL combine drills?

The Flynn EffectThe Flynn EffectSince the advent of intelligence Since the advent of intelligence

tests, people’s IQ scores have tests, people’s IQ scores have been improving with time been improving with time (flynn effect).(flynn effect).

If standardized with today’s If standardized with today’s tests, scores 80 years ago tests, scores 80 years ago would have a average IQ of 76. would have a average IQ of 76.

Possible Causes?Possible Causes?

The Flynn EffectThe Flynn Effect

70

75

80

85

90

95

100

105

1910 1930 1950 1970 1990

Year

IQ scores

Low Extreme of Low Extreme of IntelligenceIntelligence

Mental Retardation:Mental Retardation: condition of condition of limited mental ability, indicated by limited mental ability, indicated by an intelligence score of below 70 an intelligence score of below 70 andand difficulty adapting to the difficulty adapting to the demands of life.demands of life.

Caused by genetic disorders, Caused by genetic disorders, difficulties during childbirth, and difficulties during childbirth, and women who drink and use drugs women who drink and use drugs while pregnant.while pregnant.

Low Extreme of IntelligenceLow Extreme of IntelligenceDown Syndrome:Down Syndrome: condition condition

of retardation and associated of retardation and associated physical disorders caused by physical disorders caused by an extra chromosome in one’s an extra chromosome in one’s genetic makeup. genetic makeup.

Many mentally retarded Many mentally retarded people with Down Syndrome people with Down Syndrome can adapt to disorder and can adapt to disorder and some have earned college some have earned college degrees with accomodations…degrees with accomodations…nearly all learn how to read. nearly all learn how to read.

Degrees of Mental Degrees of Mental RetardationRetardation

Degrees of Mental Retardation

Level Typical Intelligence Scores Percentage of the Retarded Adaptation to Demands of Life

Mild 50-70 85% Most learn academic skills up to sixth-grade level. Adults may, with assistance, achieve self-supporting social and vocational skills.

Moderate 35-49 10 May progress to second-grade level. academically. Adults may contribute to their own support by labor in sheltered workshops.

Severe 20-34 3-4 May learn to talk and perform simple work tasks under close supervision but are generally unable to profit from vocational training.

Key Dynamic of IntelligenceKey Dynamic of IntelligenceCreativity: Creativity: the ability to produce the ability to produce

novel and valuable ideasnovel and valuable ideascomponents of creativity:components of creativity:

expertiseexpertiseimaginative thinking skillsimaginative thinking skillsventuresome personalityventuresome personalityintrinsic motivationintrinsic motivationcreative environmentcreative environment

Is Intelligence Genetic or Is Intelligence Genetic or Environmental?Environmental?

Influenced Influenced by both, by both, but the but the most most genetically genetically similar similar have the have the most most similar similar scores.scores.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0Similarity ofintelligence

scores(correlation)

Identicaltwinsreared together

Identicaltwinsreared apart

Fraternaltwinsreared together

Siblingsreared together

Unrelatedindividualsreared together

Genetic InfluencesGenetic InfluencesWith age, genetic influences become With age, genetic influences become

more apparent.more apparent.Adopted children’s intelligence scores Adopted children’s intelligence scores

become more like their biological become more like their biological parents, and identical twins parents, and identical twins similarities continue to increase as similarities continue to increase as they age. they age.

Still hard to tell what percentage of Still hard to tell what percentage of intelligence comes from genes to intelligence comes from genes to account for differences between account for differences between people (heritability). people (heritability).

Genetic InfluencesGenetic Influences

0.35

0.30

0.25

0.20

0.15

0.10

0.05

0.003 years 16 years

Child-parentcorrelation inverbal ability

scores

Children and theirbirth parents

Adopted childrenand their birthparents

Adopted childrenand their adoptiveparents

Schooling EffectSchooling Effect

Grade 6

Grade 5

Grade 4

110 115 120 125 130 135 140 145 150Age in months

118

115

112

109

106

103

100

97

IQ gains relativeto grade 4

baseline

Group Differences in Group Differences in Intelligence Scores Are Probably Intelligence Scores Are Probably

Mostly Attributed to the Mostly Attributed to the EnvironmentEnvironment

Variation within group

Variation within group

Difference within group

Poor soil Fertile soil

Seeds