Chapter 4: Heritability and IQ Flashcards
In a family study, why might your close cousin and grandparent have IQ scores correlated with you at the same level—despite clear differences in relatedness?
You share more of your developmental environment with your cousin than with your grandparent.
Why should we care about the ‘Norm of Reaction’?
The ‘Norm of Reaction’ describes several situations where individuals with identical genetics can have drastically different outcomes that are considered entirely heritable. Yet, in reality, these are entirely environmentally determined. We care about this norm because it is a flaw with our heritability metric. It explains that we have a huge range of possible expressions based upon our environmental support. Ex. Think back to the plant seed example with the varied watering and nutrient provision.
How can we explain changes in heritability over the life course?
Environmental conditions either become more or less stable over the life course.
Although infant IQ tests are effectively useless, we do have another measure of later IQ. What measure can effectively predict an infants intelligence at a later period?
“…the speed at which a child habituates during the habituation paradigm and the greater their preference for the novel stimulus in the habituation paradigm, the higher their adult IQ…”
The success of youth intervention programs—in promoting a higher IQ, alongside other positive outcomes—is reliant on what factor?
Intervening before the age of three—and ideally in infancy.
At what level, roughly, does IQ tend to predict positive life outcomes?
Between .5 and .6 depending on the study.
At which age does IQ become the most stable trait measurable?
Age 5.
What do studies of the shared versus non-shared environment tell us about sibling similarity?
Siblings are more different, on average, than are two strangers.
What are the four sub-scales of an intelligence test?
1) Verbal comprehension 2) Perceptual reasoning 3) Working memory 4) Processing speed
What is the relationship between IQ and summer break across high and low SES children?
“Children from high-SES (socio-economic status) and low-SES families both show an increase in IQ throughout the school year… However, the drop in IQ that is seen over the summer is much more pronounced in children from low- SES families compared to children from high-SES families.”
What function do infant intelligence tests serve? Why is it not useful as a general metric?
The detection of intellectually delayed children. “…some cognitive functions that underlie adult intelligence, language, abstract reasoning, problem solving, have not yet developed in these pre- verbal infants.” This means that Bayley’s infant IQ test has no ability to predict adult IQ.
To what degree do a school’s financial and physical resources predict their student’s IQ scores?
“You may be surprised to know that the financial resources of the school, the physical resources of the school and class size do not predict student’s performance on IQ tests.”
The ‘Fallacy of Exclusive Determinism’ was a central theme for this chapter. Can you explain this concept in simple words?
Our intuition that an event has a single, identifiable cause. Leads to the nature vs. nurture argument among others.
Who was the initial Binet-Simon metric designed to measure?
Children.
For the sake of this course, what is Galton known for?
Creating regression analysis and then, subsequently, the heritability statistic through studies of MZ versus DZ twins.
