Question 1

The heritability coefficient of intelligence is roughly .8.

Accepted Answer

The heritability coefficient of intelligence is generally estimated to be around 0.5 to 0.7, not 0.8. Heritability can vary based on the population and environment studied.

Question 2

Absolute intelligence tends to increase over the course of an individual's lifetime.

Accepted Answer

Intelligence, particularly fluid intelligence, which involves problem-solving and the ability to learn new information, tends to peak in early adulthood and can decline over time. Crystallized intelligence, related to accumulated knowledge and skills, may remain stable or even increase until later in life, but the overall capacity for new cognitive processing does not generally increase with age.

Question 3

As environments become more similar, the heritability coefficient of intelligence decreases.

Accepted Answer

The heritability coefficient of intelligence can actually increase in more similar environments because heritability measures the proportion of variation in a trait (like intelligence) that can be attributed to genetic variation, and in more uniform environments, differences due to genetics become more pronounced.

Question 4

Relative intelligence stays approximately constant over the course of an individual's lifetime.

Accepted Answer

Relative intelligence, often measured as IQ, tends to remain stable over a person's lifetime, although absolute cognitive abilities can change with age.

Question 5

As the number and variety of nonshared experiences in a population increases, the heritability coefficient of intelligence will decrease.

Accepted Answer

Heritability estimates for a trait depend on the degree of genetic and environmental variation in the population being studied. As nonshared experiences (such as unique life experiences and environmental factors) increase, the environmental variation increases, and the influence of genetics on intelligence decreases, leading to a decrease in the heritability coefficient.

Question 6

Fraternal twins share more genetic material than biological siblings (two parents in common) who are not born at the same time.

Accepted Answer

Fraternal twins share the same amount of genetic material as biological siblings, which is about 50%, because they are the result of two separate eggs being fertilized by two separate sperm.

Question 7

In a large and diverse population, about 50 percent of the variability in intelligence scores can be accounted for by genetic factors.

Accepted Answer

Studies on twin and adoption have shown that genetic factors play a large role in determining intelligence scores. However, it is important to note that environmental factors also contribute significantly to intelligence. Therefore, the exact percentage of variability in intelligence scores accounted for by genetic factors may vary depending on the specific population being studied.

Question 8

The IQ correlation of biological siblings raised in different households is about the same as the IQ correlation of biological siblings raised in the same household, illustrating the role of genetics in influencing intelligence.

Accepted Answer

The answer of The IQ correlation of biological siblings raised...

Question 9

The Flynn Effect refers to the fact that absolute intelligence scores are increasing across generations.

Accepted Answer

The Flynn Effect is a well-documented phenomenon where IQ scores have been increasing over time, and it is widely accepted that this is due to environmental factors such as improved nutrition, education, and access to information. However, it is important to note that the Flynn Effect only applies to IQ scores and not to other measures of intelligence.

Question 10

First-born children tend to have higher IQs than their later-born siblings.

Accepted Answer

Various studies have shown that first-born children often have higher IQs than their siblings. Some researchers have suggested that this may be due to the fact that parents tend to provide more intellectual stimulation for their first child, or because older siblings may act as "teachers" for their younger siblings, helping to enhance their cognitive development.

Question 11

Identical twins are also called dizygotic twins.

Accepted Answer

Identical twins are actually called monozygotic twins, while dizygotic twins are fraternal twins who develop from two separate sets of eggs and sperm.

Question 12

Increases in the genetic similarity of a population are associated with an increased heritability coefficient of intelligence.

Accepted Answer

The answer of Increases in the genetic similarity of a...

Question 13

The heritability of intelligence generally increases with the age of the sample measured.

Accepted Answer

As people age, their environments become more similar due to shared experiences such as education and employment. Therefore, genetic differences become more pronounced in influencing intelligence.

Question 14

First-born children tend to have higher IQs because they receive more parental attention than their later-born siblings.

Accepted Answer

This is a commonly accepted theory known as the "birth order effect." The first-born child typically receives more one-on-one attention from parents in their early years, which can positively impact their cognitive development and result in higher IQ scores. However, it's important to note that this is not a universal rule and there are many other factors that can impact a child's intelligence.

Question 15

The heritability coefficient of intelligence is lower in children from low-SES families than in children from high-SES families.

Accepted Answer

Studies have shown that the heritability coefficient of intelligence is lower in children from low-SES families (i.e. those with lower socio-economic status) than in children from high-SES families (i.e. those with higher socio-economic status). This is because environmental factors such as access to quality education, nutrition, and healthcare can have a significant impact on a child's cognitive development and ability to reach their full potential.

Question 16

Fraternal twins are also called monozygotic twins.

Accepted Answer

Fraternal twins are actually called dizygotic twins, while monozygotic twins are identical twins.

Question 17

Monozygotic twins share 100 percent of their genes.

Accepted Answer

Monozygotic twins, also known as identical twins, develop from a single fertilized egg that splits into two embryos. As a result, they share the same DNA and are essentially genetic replicas of each other. Therefore, they share 100 percent of their genes.

Question 18

The heritability coefficient of intelligence provides a rough estimate of how much of an individual's intelligence is determined by genes and how much of it is determined by environmental factors.

Accepted Answer

The answer of The heritability coefficient of intelligence provides a...

Question 19

The IQ correlation between siblings decreases as the age difference between them increases.

Accepted Answer

Studies have shown that the correlation between the IQ scores of siblings decreases as the age difference between them increases. This is likely due to environmental factors such as different experiences, education, and opportunities as they grow older. However, genetics still plays a role in determining IQ, so there will always be some correlation between the IQ scores of siblings no matter the age difference.

Question 20

The IQ correlation of identical twins raised apart is higher than that of fraternal twins raised in the same household.

Accepted Answer

This is because identical twins share 100% of their DNA while fraternal twins share only 50%, making it more likely that their IQs will differ. Additionally, being raised in the same household can introduce environmental factors that may affect IQ scores, while being raised apart reduces these environmental influences.

Quiz 10: Section 4 : Intelligence