Question 1

Which of the following is the best evidence for a genetic contribution to intelligence?
A) the high correlation between intelligence scores of close biological relatives
B) the fact that aptitude test scores of identical twins reared together tend to be more highly correlated than the scores of identical twins reared apart
C) the fact that intelligence scores of identical twins tend to be more similar than those of fraternal twins
D) the fact that intelligence scores of fraternal twins tend to be more similar than those of non-twin siblings

Accepted Answer

Identical twins share 100% of their genes, so the higher similarity in their intelligence scores compared to fraternal twins, who share about 50% of their genes, suggests a genetic contribution to intelligence.

Question 2

Studies comparing identical and fraternal twins reveal that __________.
A) identical twins have more highly correlated intelligence scores
B) identical twins are generally better in verbal tasks than fraternal twins
C) identical twins have higher IQ scores than fraternal twins
D) both groups have equally highly correlated intelligence scores

Accepted Answer

Studies comparing identical and fraternal twins have consistently found that identical twins have more highly correlated intelligence scores than fraternal twins, indicating that genetics plays a stronger role in intelligence than environmental factors.

Question 3

Which of the following most closely approximates the correlation a researcher might find between the intelligence test scores and the household incomes of a sample of American adults?
A) .91
B) .36
C) -.41
D) .05

Accepted Answer

There is a positive correlation between intelligence and income, but it is not perfect (i.e. not close to 1). A correlation of .36 would indicate a moderate positive correlation, suggesting that as intelligence test scores increase, so does household income, but there is still variability in the relationship. Choices A and D are too high and suggest a near perfect positive or positive correlation, respectively. Choice C is negative, which suggests intelligence test scores and household incomes are inversely related, which is not supported by research.

Question 4

A researcher finds a significant correlation between the IQ scores and the SES of a large sample of American adults. Which of the following can she conclude?
A) Low IQ produces low SES.
B) High IQ leads to high SES.
C) SES is related to IQ.
D) Low SES results in low IQ.

Accepted Answer

The significant correlation between IQ scores and SES indicates that the two variables are related, but this correlation does not imply causation. It is possible that IQ influences SES or that SES influences IQ, or that there is a third variable that affects both. Therefore, the researcher cannot conclude that one variable causes the other. The best conclusion that can be drawn from the correlation is that there is a relationship between IQ scores and SES.

Question 5

An individual's phenotype __________.
A) is a direct expression of his or her genotype
B) is different from, and independent of, his or her genotype
C) depends on the interaction between an individual's genotype and his or her environment
D) cannot be changed

Accepted Answer

An individual's phenotype depends on the interaction between his or her genotype and environmental factors. While genetics plays a role in determining how an individual develops and looks, environmental variables such as nutrition, exposure to toxins, and lifestyle can also shape an individual's phenotype. This is why identical twins, despite having the same genotype, can have differences in their phenotype due to differences in their environment.

Question 6

Rosa is a toddler in Sao Paulo, Brazil. That she is learning language is __________. That she is learning Portuguese is __________.
A) environmental; environmental, too
B) environmental; genetic
C) genetic; genetic, too
D) genetic; environmental

Accepted Answer

The fact that Rosa is learning language is due to environmental factors, such as exposure to language and interaction with caregivers. However, the specific language she is learning (Portuguese) is determined by her cultural and environmental background, which are both environmental factors. Therefore, her ability to learn language is genetic but the specific language she is learning is environmental.

Question 7

When we compare the similarity in intelligence scores for identical twins reared together with identical twins reared apart, we find that identical twins reared apart __________.
A) are significantly less similar than are identical twins reared together
B) are nearly as similar as identical twins reared together
C) are as similar as identical twins reared together in mathematical skills but significantly different in verbal abilities
D) score significantly lower than identical twins reared together

Accepted Answer

Research studies have found that identical twins reared apart have very similar intelligence scores, nearly as high as those of identical twins reared together. This suggests that genetics play a strong role in determining intelligence, although environmental factors also have some influence. Option A and Option D are incorrect because it is not true that identical twins reared apart score significantly less or lower than identical twins reared together. Option C is incorrect because there is no empirical evidence to support that identical twins reared apart are as similar as identical twins reared together in mathematical skills but significantly different in verbal abilities.

Question 8

Your text reports that in the early 20th century, a congressional committee examined the scores of immigrant groups on the U.S. Army's intelligence test. Which of the following statements is consistent with the claims of the committee?
A) Intelligence primarily reflects the influence of genes.
B) The immigrants' scores reflect the length of time they have spent in the United States.
C) Intelligence may be increased by enriching the environment.
D) The U.S. Army's intelligence test is culture-fair.

Accepted Answer

The answer of Your text reports that in the early...

Question 9

The term phenotype refers to an organism's __________.
A) recessive genes
B) visible structure and behavior
C) genetic blueprint
D) shared characteristics with offspring

Accepted Answer

The term phenotype refers to an organism's visible structure and behavior, or the physical and behavioral traits that are exhibited as a result of an individual's genetic makeup and environmental factors. This can include traits such as eye color, height, and behavior patterns.

Question 10

An individual's observable characteristics are its __________.
A) phenotype
B) genotype
C) PKU
D) recessive genes

Accepted Answer

An individual's observable characteristics, such as physical traits, are known as their phenotype. Genotype refers to an individual's genetic makeup. PKU is a genetic disorder and recessive genes are a type of gene that is only expressed when paired with another recessive gene.

Question 11

If we compare the correlation between adopted children's intelligence scores and those of their biological and adoptive mothers, we find that __________.
A) in both childhood and adolescence, children's intelligence scores are more highly correlated with those of their biological mothers than with those of their adoptive mothers
B) in both childhood and adolescence, children's intelligence scores are more highly correlated with those of their adoptive mothers than with those of their biological mothers
C) in childhood, children's intelligence scores are more highly correlated with those of their biological mothers, while in adolescence children's intelligence scores are more highly correlated with those of their adoptive mothers
D) in childhood, children's intelligence scores are more highly correlated with those of their biological mothers, while in adolescence, their scores are equally correlated with those of their biological and adoptive mothers

Accepted Answer

The question states that if we compare the correlation between adopted children's intelligence scores with those of their biological and adoptive mothers, we find that children's intelligence scores are more highly correlated with those of their biological mothers than with those of their adoptive mothers in both childhood and adolescence. Therefore, option A is the correct answer.

Question 12

Which of the following is inconsistent with the idea that there is a hereditary component in the development of intelligence?
A) more highly correlated intelligence scores for identical than fraternal twins
B) greater similarity of intelligence scores between adopted children and their biological parents than with their adoptive parents
C) more highly correlated intelligence scores for full siblings than half-siblings who share only one parent
D) a positive correlation between intelligence scores of adopted children and their adoptive parents

Accepted Answer

Choice D is inconsistent with the idea of a hereditary component in the development of intelligence because it suggests that intelligence can be influenced by environmental factors, such as being raised by intelligent adoptive parents, rather than genetics. The other choices (A, B, and C) support the idea of a hereditary component in intelligence, as they demonstrate a stronger correlation between intelligence scores for individuals who share more genetic material.

Question 13

Comparisons between the correlations of intelligence scores in identical and fraternal twins are often regarded as evidence for the role of genetic factors in the development of intelligence. This argument is based on the assumption that __________.
A) siblings have shared genes and shared environments
B) identical twins have the same phenotype
C) fraternal twins have the same genotype and different phenotypes
D) the environments of identical twins are no more similar than those of fraternal twins

Accepted Answer

The argument that comparisons between the correlations of intelligence scores in identical and fraternal twins provide evidence for the role of genetic factors in intelligence development assumes that the environments of identical twins are no more similar than those of fraternal twins. This allows any observed differences in correlation to be attributed to genetics rather than environmental factors.

Question 14

According to your text, the IQ scores of immigrants in the early 20th century reflected the length of time they have lived in the United States, rather than their true intelligence. In the language of research methodology, length of time in the United States is a(n) __________ variable in this instance.
A) confounding
B) independent
C) control
D) IQ and socioeconomic status are unrelated.

Accepted Answer

A confounding variable is one that can affect the outcome of a study and is related to both the independent and dependent variables. In this instance, the length of time in the United States is a potential confounding variable because it is related to both IQ scores (dependent variable) and immigrant status (independent variable). Therefore, it needs to be controlled for in order to accurately determine the relationship between immigrant status and IQ scores.

Question 15

An organism's genetic blueprint is called its __________.
A) expression
B) dominant gene
C) genotype
D) phenotype

Accepted Answer

A genotype refers to an organism's particular set of genes, which determine its traits and characteristics. In contrast, expression refers to how those genes are actually being used or "expressed" in the organism, while dominant genes are those that are more likely to be expressed over other genes. Phenotype refers to the physical manifestation of an organism's traits and characteristics, which is influenced both by its genotype and by environmental factors.

Question 16

Identical twins __________.
A) can differ in genotype
B) can differ in phenotype
C) can differ in both genotype and phenotype
D) arise from the simultaneous fertilization of two ova by two different sperm cells

Accepted Answer

Identical twins arise from the splitting of a single fertilized egg and therefore share the same genotype. However, environmental factors and random genetic mutations can lead to differences in their phenotype, such as differences in fingerprints, health conditions, and even personality traits.

Question 17

Fraternal twins __________.
A) are as genetically similar as non-twin siblings
B) have identical genotypes
C) originate from a single fertilized egg
D) have identical phenotypes

Accepted Answer

Fraternal twins, also known as dizygotic twins, come from two separate eggs fertilized by two different sperm. Therefore, they are no more genetically identical than non-twin siblings.

Question 18

Which of the following pairs of correlation coefficients most closely corresponds to the observed correlations between the intelligence scores of adopted children and those of their adoptive or biological parents?
A) child-adoptive: 0.15; child-biological: 0.28
B) child-adoptive: 0.28; child-biological: 0.15
C) child-adoptive: 0.90; child-biological: 0.10
D) child-adoptive: 0.10; child-biological: 0.90

Accepted Answer

Research in behavioral genetics has consistently shown that the intelligence scores of adopted children have a higher correlation with their biological parents than with their adoptive parents. This is because intelligence has a significant genetic component. The options provided suggest that the correlation with biological parents (0.28) is higher than with adoptive parents (0.15), which aligns with empirical findings.

Question 19

Dr. Hardhead has developed a measure of stubbornness and wants to determine the influence of genetics on performance on his new measure. Which of the following findings from administrations of the new test provides the best evidence for genetic influence?
A) Scores are more highly correlated in identical twins reared together than identical twins reared apart.
B) Scores are more highly correlated in identical than fraternal twins.
C) Scores are highly correlated between adopted children and their adoptive parents.
D) Scores are highly correlated between siblings.

Accepted Answer

This finding suggests that genetic factors are influencing performance on the measure of stubbornness, as identical twins share all of their genetic material while fraternal twins only share about half. A higher correlation in scores between identical twins compared to fraternal twins therefore suggests a stronger genetic influence on performance.

Question 20

Your text reports that in the early years of the 20th century, advocates for the disadvantaged argued that good education can lift the IQ scores of the disadvantaged. In light of subsequent research, were the advocates correct?
A) No. Intelligence largely reflects genetic mechanisms.
B) Yes. A lack of schooling results in continuing declines in IQ.
C) Somewhat. Increases in IQ scores stemming from enriched education are generally short-lived.
D) I'm not sure. Little research has examined the potential effect of education on IQ scores.

Accepted Answer

Research has shown that education can have a significant impact on IQ scores, and lack of schooling can lead to declines in IQ.

Quiz 11: Intelligence

Which of the following is the best evidence for a genetic contribution to intelligence?

Studies comparing identical and fraternal twins reveal that __________.

Which of the following most closely approximates the correlation a researcher might find between the intelligence test scores and the household incomes of a sample of American adults?

A researcher finds a significant correlation between the IQ scores and the SES of a large sample of American adults. Which of the following can she conclude?

An individual's phenotype __________.

Rosa is a toddler in Sao Paulo, Brazil. That she is learning language is . That she is learning Portuguese is .

When we compare the similarity in intelligence scores for identical twins reared together with identical twins reared apart, we find that identical twins reared apart __________.

Your text reports that in the early 20th century, a congressional committee examined the scores of immigrant groups on the U.S. Army's intelligence test. Which of the following statements is consistent with the claims of the committee?

The term phenotype refers to an organism's __________.

An individual's observable characteristics are its __________.

If we compare the correlation between adopted children's intelligence scores and those of their biological and adoptive mothers, we find that __________.

Which of the following is inconsistent with the idea that there is a hereditary component in the development of intelligence?

Comparisons between the correlations of intelligence scores in identical and fraternal twins are often regarded as evidence for the role of genetic factors in the development of intelligence. This argument is based on the assumption that __________.

An organism's genetic blueprint is called its __________.

Identical twins __________.

Fraternal twins __________.

Which of the following pairs of correlation coefficients most closely corresponds to the observed correlations between the intelligence scores of adopted children and those of their adoptive or biological parents?

Dr. Hardhead has developed a measure of stubbornness and wants to determine the influence of genetics on performance on his new measure. Which of the following findings from administrations of the new test provides the best evidence for genetic influence?

Your text reports that in the early years of the 20th century, advocates for the disadvantaged argued that good education can lift the IQ scores of the disadvantaged. In light of subsequent research, were the advocates correct?