EXTREMES OF INTELLIGENCE

MENTAL RETARDATION• DEF: subaverage general mental ability accompanied by deficiencies in adaptive skills, originating before age 18

• IQ score of 70 or lower• 1-3% of the population

LEVELS OF RETARDATION• Characterized as mild, moderate, severe, or profound

• Most fall under mild• Majority are unrecognizable outside of schooling

Super Swaggy!

ORIGINS OF RETARDATION• Down syndrome involves and extra chromosome

• Phenylketonuria is an inherited enzyme deficiency

• Hydrocephaly is an excessive accumulation of cerebrospinal fluid in the skull

GIFTEDNESS• Identifying giftedness comes from IQ tests• Upper 2-3% of scores are considered gifted (130)• Gifted tend to be above avg in height, weight, strength,

emotional adjustment, mental health, and social maturity (Terman)

• Profoundly gifted (scores of 180+) are often introverted and socially isolated (Winner)

HEREDITARY AND ENVIRONMENT AS DETERMINANTS OF INTELLIGENCE

TWIN STUDIES IN INTELLIGENCE• Twins develop in similar environments and share genetic kinship

• Even identical twins raised in separate environments show similar IQs

HERITABILITY ESTIMATES• Heritability ratio: an estimate of the proportion of trait variability in a population that is determined by variations in genetic inheritance

EVIDENCE FOR ENVIRONMENTAL INFLUENCE

• Adopted children show more similarity in IQ to their adoptive parents

• Cumulative deprivation hypothesis: children who are raised in substandard circumstances should experience a gradual decline in IQ as they grow older

GENERATIONAL CHANGES: THE FLYNN EFFECT

• James Flynn discovered that IQ performance has risen steadily in the industrialized world since 1930

• Reduction in malnutrition, advances in technology, improved schools, etc…

CULTURAL DIFFERENCES IN IQ SCORES

• Larger minority groups in U.S. have lower avg IQ scores than the avg for whites

• Some believe it’s hereditary (no proof)• Others point to socioeconomic disadvantages• Stereotype vulnerability is another explanation• Some argue that IQ tests are culturally biased• Evidence shows that cultural bias produces only weak

and inconsistent effects on the IQ scores of minority examinees

NEW DIRECTIONS IN THE ASSESSMENT AND STUDY OF INTELLIGENCE

INCREASING EMPHASIS ON SPECIFIC ABILITIES

• Factor analysis: correlations among many variables are analyzed to identify closely related clusters of variables

• Attempts to identify hidden factors influencing others

• Charles Spearman

EMPHASIS ON SPECIFIC ABILITIES CONTINUED

• L.L. Thurstone concluded that intelligence involves multiple abilities

• 7 distinct factors: word fluency, verbal comprehension, spatial ability, perceptual speed, numerical ability, inductive reasoning, and memory

EMPHASIS CONTINUED• Raymond Cattell and John Horn suggest fluid and crystallized intelligence should be the divisions of intelligence

EXPLORING BIOLOGICAL INDEXES OF INTELLIGENCE

• Correlation btwn reaction time and higher IQ scores

• Correlation btwn inspection time and high IQ scores

COGNITIVE PROCESSES IN INTELLIGENT BEHAVIOR• Focuses on how people use their intelligence• Robert Sternberg• Triarchic theory of human intelligence• 3 parts:• Contextual subtheory: intelligence is a culturally defined

concept• Experiential subtheory: ability to deal with novelty and

ability to learn how to handle familiar tasks automatically and effortlessly

• Componential subtheory: describes specific types of mental processes that intelligent thought depends on

EXPANDING THE CONCEPT OF INTELLIGENCE

• Many today believe IQ test focus is too narrow

• IQ tests emphasize verbal and mathematical skills

• Howard Gardner suggests there are numerous autonomous human intelligences