Chapter 11 - Intelligence Do I belong in this class? Just Kidding

Intelligence & brain anatomy Mild relationship between brain size, shape, convolutions, etc. & intelligence –Neural plasticity – ability to grow neural connections in response to the environment More neural connections = higher intelligence –More grey matter in memory, attention, & language = higher intelligence Area may influence ability Function –Frontal lobe seems to organizing area –Brain speed influences intelligence Perceptional speed Neurological speed –Fast reaction on simple tasks predicts performance on complex tasks

Intelligence Assessments tests that measure mental aptitudes compared to others and gives them a numerical score Origins –Binet – school achievement Assumed that development of intelligence was the same for everyone but we progress at different rates Used mental age to predict child’s success in school –Not designed to measure ability to learn only ability in a grade –Terman – innate IQ Stanford-Binet test IQ = (mental age/chronological age) x 100 –100 = average intelligence Test was used to evaluate immigrants & proposed to evaluate who should reproduce

Modern tests Aptitude tests –predict ability to learn/perform skill Achievement tests –check for learning Wechsler Adult Intelligence Scale (WAIS) –11 subtests –Scores on verbal comprehension, perceptual organization, working memory, & processing speed

Principles of test construction Standardization –Representative sample determines scores Normal distribution or bell curve Normal scores fall within 2 standard deviations –Flynn effect – rising test performance scores = recalibrating tests Why? Nutrition, schooling, stimulation, smaller family, etc Reliability –Scores must be consistent (repeated) to be reliable Validity – does it measure what it’s supposed to –Content validity vs. predictive validity (criterion-related validity) –Aptitude tests lose their predictive powers with age Lower correlations with each successive tests

Dynamics of Intelligence Stability vs. change –Relatively little predictability of level of intelligence prior to age 3 –From age 4 – intelligence scores predict adolescent and adult intelligence scores –After age 7 intelligence scores stabilize Stability of math and English SAT and GRE scores –Long-term study (Deary, 2004) confirms Extremes –Low extreme Cognitive Disabled/mental impairment – low intel. score & inability to adapt Down syndrome – extra chromosome (a cause of c.g.) Care has changed –High extreme High intelligence scores don’t predict social adeptness Inclusion vs. tracking

Genetic & Environmental Influences Who gets the credit for your smarts (or lack there of)?

Genetics twin studies –nearly identical IQ scores –same amount of grey matter genetic mapping trappings of heritability

Environment orphanage study –deprivation of normal interaction delays development poverty affects nutrition therefore development –poor environment not as “advantaged” as others school has an effect –higher IQ scores in vs. out of school –Flynn effect – the gradual increase of intelligence from generation to generation

Group differences Ethnic differences in IQ scores do exist –Avg. scores white = 100, black = 85, Hispanic approx –Not able to predict just an average Race differences –alikeness between races, more variety within races genetically more similar to some races that look less alike –A social definition not biological – diverse ancestry –Asians score highest on math aptitude Attend 30% more school days More studying out of school –1930’s vs. today = blacks vs. whites nutrition, ed., opportunities, etc.

Group differences Gender differences –girls score higher on spelling, verbal and non-verbal ability (memory), sensation (touch, taste, odor) –boys are more prevalent in underachievement = special education –math boys outnumber girls at the highest and lowest levels boys rate higher on spatial reasoning boys show math problem-solving abilities

Bias in Intelligence Testing Cultural differences because of experience not ability Is the test less valid for some groups? –Statistically