Biology of intelligence Flashcards
Four biological factors…
That many underlie intelligence
1. Brain size
2. Speed and efficiency of neural transmission
3. Working memory
4. Sensory ability
Brain size
Studies measured brain volume using neuroimaging techniques.
- Larger brain size is correlated with intelligence
- Intelligence has been found to be correlated with the number of neurons in the brain and with the thickness of the cortex.
A stimulating environment that rewards thinking and learning may lead to greater brain growth.
Also possible that a third variable, such as better nutrition, causes both brain volume and intelligence.
Faster and more efficient neurons
- People who are more intelligent frequently show less brain activity than those with lower intelligence when they work on a task.
- Brains of more intelligent people also seem to run faster than the brains of the less intelligent people.
Working memory
- Manipulates visual and auditory information
- Sustains attention
- Impacts school performance and IQ
- Can be trained using exercises
- Temporary storage
Used as a measure of intelligence on many teats.
Scores also correlates at about r=.5 with measures of working memory.
○ Impacts school performance and IQ
○ Is now used as a measure of intelligence of many tests.
40% of variability of IQ explained by genetic
Importance of biology
Biology is important because intelligence, or IQ is quite heritable with at lease 40% of variability of IQ being explained by genetics.
Nature
The IQs of identical twins correlate very highly (r = .86), much higher than do the scores of fraternal twins who are less genetically similar (r = .60).
The correlations between the IQs of parents and their
biological children (r = .42) is significantly greater than the correlation between parents and adopted children (r = .19)
The role of genetics
The role of genetics gets stronger as children get older.
- The intelligence of children (less than 3 years old) does not predict adult intelligence.
- By the age of 7 it does.
IQ scores remain very stable in adulthood.
Nurture
Indicates that individuals are not born with fixed, unchangeable levels of
intelligence.
- Twins raised together in the same home have more
similar IQs than do twins who are raised in different homes, and fraternal twins have more similar IQs than do nontwin siblings, which is likely due to the fact that they are treated more similarly than nontwin siblings are.
Environmental Factors
Environmental factors play a huge role.
More variability in low economic households: the basics of diet, exercise, low toxins.
This is because most upper
-class households tend to provide a safe, nutritious, and supporting environment for children, whereas these factors are more variable in
lower-class households.
Social and Economic factors
Can adversely affect IQ.
Children from households in poverty have lower IQs than do children from households with more resources even when other factors such as education, race, and parenting are controlled.
Poverty may lead to diets that are undernutrition or lacking in appropriate vitamins, and poor children may also be more likely to be exposed to toxins such as lead in drinking water, dust, or paint chips.
Both factors can slow brain development and reduce intelligence.
Early experience
The fact that intelligence becomes more stable as we get older provides evidence that early environmental experiences matter more
than later ones.
Steve Ceci
American Psychologist, school does make us more intelligent
Intelligence is improved by education.
The number of years a person has spent in school correlates at about r = .6 with IQ.
- correlation may be due to the fact that people with higher IQ scores enjoy taking classes more than people with low IQ scores, and thus they are
more likely to stay in school.
Education has a casual effect on IQ.
- Children who enter a school a year earlier have higher IQ than those who have to wait until next year to begin.
Children’s IQ tend to drop significantly during summer vacations.
- a finding that suggests that a longer school year, as is used in Europe and East Asia, is beneficial
Emotional regulation
Refers to the ability to control and productively use one’s emotions.
- people who are better
able to override their impulses to seek immediate gratification and who are less impulsive also have higher cognitive and social intelligence. - they have better test scores, and are rated by their friends as more socially adept, and cope with frustration and stress better than those with less skill at emotion regulation.
Intelligence and the bell curve
- About 2% are gifted
- About 95% of people fall in the range within 30 points of 100.
- About 68% of people fall in the rage within 15 points of 100.
- About 2% are intellectually disabled.
Average Intelligence
The majority of us have average intelligence.
