One of the most difficult and controversial issues in psychology is sorting out the effects of nature and nurture.
Nature and nurture both stress the importance of the environment and learning.
Intelligence is one of the more controversial aspects of the nature-nurture debate.
Nature and nurture affect human intelligence.
Genetic and environmental factors play a role in intelligence.
Heritability is an important term used in discussing the effects of nature and nurture.
Heritability is how much of a trait's variation is explained by genetic factors.
Heritability can range from 0 to 1, where 0 indicates that the environment is responsible for differences in the trait and 1 means that all of the variation in the trait can be accounted for genetically.
It's important to point out that heritability doesn't apply to an individual but to a population.
The heritability ratio won't tell us how much of a person's intelligence was determined by nature or nurture.
We can't ethically set up a controlled experiment to provide definitive answers to this question, so we can't solve it once and for all.
The Flynn effect is a finding that shows the increasing performance on intelligence tests.
Environmental factors such as nutrition, education, and television and video games are thought to play a role in intelligence.
Twins who share 100 percent of their genetic material score better on intelligence tests than twins who have only 50 percent of their genes in common.
Monozygotic twins tend to be treated the same as dizygotic twins, according to some researchers.
There are correlations in intelligence scores between identical twins separated at birth.
It is difficult to discern the relative effects of nature and nurture when the twins are placed into similar environments.
If each of the twins is placed into a white, middle-class, suburban home, concluding that all their similarities are genetically based does not make sense.
Some researchers argue that intelligence is largely determined by genetics.
The majority of psychologists believe that the racial differences are more likely explained by differences in environments.
African Americans tend to score less on IQ tests than whites.
Many researchers believe that the main cause of the disparity in test scores is the poverty level of the minority population.
The gap in test scores may be contributed to by test bias.
Head Start, a government program meant to help poor people, has been shown to correlate with higher scores on intelligence tests.
Opponents of such programs say that the gains are limited.
It is unreasonable for advocates of such interventions to expect the gains to last.
When comparing groups of people on any characteristic, keep in mind that differences within groups tend to dwarf differences between groups.
In other words, any one group will be more diverse than any other.
More of a difference will exist between the highest scoring boy and the lowest scoring boy than between the average boy and the average girl if we find that boys perform better on certain tests than girls do.
Knowing that boys generally perform better than girls on this test tells us nothing about the performance of any particular girl.
We need to be careful about how we use the information.
We should evaluate each person as an individual, regardless of group membership.
Between-group differences are smaller than within-group differences.
It is said that we live in a testing society.
We like to measure things and assign them a number.
Keeping in mind the limitations and extraordinary labeling power of these instruments is important.
Many factors affect people's performances on tests, and the definition of intelligence is still being debated.
We need to be careful not to say too much about a test score.
Many schools have stopped measuring all their students' IQs.
Schools that used to base admission to programs for exceptional children solely on these tests now gather information in other ways as well.
When IQ tests are given, the results remain confidential so as not to create expectations about how people should perform.
Well-designed tests can be useful, but we must recognize their limitations.
Five suggested answers or completions are followed by each of the questions or incomplete statements.
Pick the one that is the best.
Paul took a test in the army to see if he would be a good pilot.
Mrs. Cho is careful to make sure that she does not plagiarize the entire year's work on the final exam for her American literature class.
Mary is very popular and outgoing despite her low score on the personality test.
He has a mental age of 10 and is 8 years old.
Nature is more important than nurture in shaping personality according to Desmond.