What Causes IQ? Genetic & Environmental Factors

Question 1

Brain regions associated with intelligence

Answer 1

frontal, parietal, and temporal lobes associated with g; prefrontal cortex, parietal lobe linked to fluid intelligence; temporal lobes linked to crystallized intelligence; white matter linked to processing speed

Question 2

Higher IQ equals?

Answer 2

Less, more efficient brain activity

Question 3

Brain volume?

Answer 3

Modestly/moderately correlated w/ intelligence

Question 4

What does plasticity suggest?

Answer 4

brain structures and functioning are not nly determined by genes but also by our experiences; higher IQ may be associated with greater plasticity

Question 5

IQ heritability is likely between?

Answer 5

0.4-0.8, but common to hear “about 50%”

Question 6

Studies explain how much of IQ based on gene regions?

Answer 6

5%

Question 7

Factors reliably related to intelligence/achievement (8)

Answer 7

SES; Enriched home environment; Nutrition; Teratogens/toxins; Low birth weight; Early language exposure; Birth Order; Schooling

Question 8

Chronic stress does what to where?

Answer 8

Damages the brain; prefrontal cortex (self-regulation) and hippocampus (memory)

Question 9

Stereotype Threat (Steele & Aronson, 1995)

Answer 9

Awareness of stereotype–>Threat of devaluation–>Arousal & anxiety–>Impaired executive functioning–>Poorer performance on complex tasks

Question 10

The paradox of intelligence

Answer 10

high heritability AND malleability

Question 11

GxE correlation

Answer 11

individuals with a particular genotype are more likely to experience particularly relevant environments

Question 12

GxE interaction

Answer 12

There is a different effect of a relevant environment depending on an individual’s genotype

Question 13

Three gene-environment correlations (rGE)

Answer 13

1) passive: the environment parents create 2) reactive: what the individual evokes from others 3) active: the environment the individual selects

Question 14

The individual multiplier

Answer 14

Gene leads one to experience environments that strengthen genetic tendencies over time; the environment reinforces our dispositions; may explain why heritability increases over the lifespan

Question 15

Scarr-Rowe Hypothesis

Answer 15

Gene X SES interaction: Lower heritability of IQ among those from low SES backgrounds; Two ways of thinking 1) natural potential is more fully expressed in nurturing environments OR 2) poverty suppresses a child’s ability to develop to their full potential; May be moderated by the amount of social stratification

Question 16

Social Multiplier

Answer 16

High levels of intelligence in a community can have a spillover effect on the individual; Example: the environment shifts to accommodate the needs of a high IQ community and the individual benefits from these changes; May be another reason why heritability increases with SES

Question 17

Life outcomes and intelligence

Answer 17

Strong relationship between intelligence and life outcomes such as self-control, health, longevity, occupational success