AP Psych: Intelligence Testing

Brain Size

 Galton correlated student’s grade point average to head size

• Popularized eugenics movement

Binet-Simon Intelligence Scale (1905)

Test addressed memory, common knowledge, etc. Used exam to divide “normal” students from less able students to target for special needs

Mental Age

intellectual capability of someone compared to average individuals of same age

Stanford-Binet

Lewis Terman (Stanford) Univ) revises test for a score and new age norms for use in US

Intelligence Quotient (Stanford-Binet)

(mental age/ chronological age)x100

Buck v Bell

• Supreme Court that such sterilizations at the state level were constitutional

  • Carrie Buck was designated as “feebleminded” and institutionalized then sterilized 

Stanford Binet Intelligence Test

Consists of verbal and non-verbal tasks

ii. 5 tested factors: quantitative reasoning, visual-spatial processing, working memory, and fluid reasoning.

Wechsler Adult Intelligence Scale (WAIS-III) and Wechsler Intelligence Scale for Children (WISC-III)

1. IQ test with sections including Verbal (e.g. vocab) and Performance Sections (assembling an object)

2. Most widely used today

Intellectual Disability and IQ

a. Borderline = 50 – 75 (70% of individuals)

b. Mild/Moderate = 35 – 50 

c. Severely = 20-40 

d. Moderately Gifted = 130 – 150 (2% of pop)

e. Profoundly Gifted = 180 + (.0000001 % of pop) 

Flynn Effect

3. Q scores have been rising 

   1. Current Data indicates leveling off or possible decline

Cross-Sectional Studies

1. show decline in IQ as we age

   1. Problem: studies compared two different eras (those who grew up in 00’s to those in the 50’s) = different environmental condition

Longitudinal Studies

1. show relatively stable IQ

   1. Problem: Those who survive to participate may be the most intelligent

   2. Recent studies show more decline especially after age 85

Crystallized Intelligence

(accumulated knowledge) increases with age-Vocab+Analogy tests

Fluid Intelligence

(reasoning speed and abstract thinking) decreases slowly with age – past 75 more rapidly

Nature/Nurture:Twin Studies

1. Identical twins IQs correlate very highly regardless of being raised together and apart (although twins raised together are more similar) 

2. Similarities increase with age

3. Twins are more similar than non-twin siblings

Nature/Nurture:Adoption Studies

1. Some children adopted out of impoverished conditions do show a substantial increase in scores

2. Correlations between adopted children and their siblings/parents start to wane over time

Nature/Nurture:Early Environment 

1. Severe deprivation is correlated with cognitive/emotional delays

2. Intervention Programs (e.g. Head Start)

   1. shown to support academic, emotional, and social growth (better behavior/grad rates)

   2. Initial boosts in IQ fade over time

3. Enrichment Products (e.g. Baby Einstein)

   1. not shown to produce any effects when compared to control

Modern Testing:Intelligence

test innate cognitive ability (e.g. Stanford-Binet)

Modern Testing:Achievement

what you have learned (AP Exam)

Modern Testing:Aptitude

predicts ability to learn a new skill (e.g. SAT) *some studies show high correlation between IQ and SAT scores* 

Test Construction:Standardization

Part I

Establishing uniform testing procedures, then issuing test to a representative sample

Test Construction:Standardization

Part II

Establishing norms from the scores of the sample

Test Construction:Standardization

Part III

using norms from sample to compare to all future test takers.

Test Construction:Reliability

test scores are consistent over time on similar tests

Test Construction: Test-Retest Method (Reliability)

give same test to same group at separate sittings

Problem =  Testing Effect

Test Construction: Alternate Form (Reliability)

two versions of test to same group at separate sittings

Problem = slight variations in difficulty

Test Construction:Validity

test measures what it is supposed to

Test Construction: Content (Validity)

measures all the knowledge intended

Test Construction: Criterion (Validity)

extent to which it is correlated with other accepted measures (eg. Stanford vs WAISC)

Test Construction: Predictive (Validity)

how accurately it forecasts performance (e.g. SAT)

Test Construction: Construct (Validity)

measures hypothetical construct accurately (IQ tests, MMPI – 2 Schizophrenia)