Question 1

One problem with studying identical and fraternal twins raised together or apart is that:

Accepted Answer

The fact that identical twins raised together may be treated more similarly than fraternal twins raised together could account for their greater behavioural similarity, making it difficult to determine if their similarities are due to genetics or environmental factors. A, C, and D are not accurate descriptions of the problems with studying twins.

Question 2

What do we currently know about the specific sizes of reaction ranges for individuals?

Accepted Answer

The answer of What do we currently know about the...

Question 3

Barbara and Brenda are identical twins who were adopted at birth and raised by two different families.Andy and Andrew are identical twins raised together by their biological parents.When the four children entered high school they took an IQ test.Barbara and Andy each had scores of 110,while Brenda's IQ was measured at 120 and Andrew scored 108.These results support which of the following conclusions?

Accepted Answer

The fact that identical twins raised in different environments (Barbara and Brenda) have different IQ scores suggests that environmental factors can influence intelligence. However, the fact that identical twins raised in the same environment (Andy and Andrew) also have different IQ scores suggests that genetics also play a role in determining intelligence. Therefore, the results support the conclusion that intelligence is shaped by both genetics and environmental influences.

Question 4

Scott and Shawn are identical twins raised together,whereas Tammy and Tracey are identical twins raised apart.Scott and Shawn are more similar on IQ than are Tammy and Tracey.This finding:

Accepted Answer

The answer of Scott and Shawn are identical twins raised...

Question 5

A genetically determined trait may have an upper and lower limit,and the environment may determine the exact level of the trait that ultimately gets expressed.This is referred to as the concept of ______.

Accepted Answer

The concept of a reaction range suggests that genetics provide an upper and lower limit for a trait, while the environment determines where the expression of the trait ultimately falls within that range. Genetic potential refers to the maximum genetic expression of a trait. Concordance refers to the degree of similarity between traits among individuals, usually with respect to genetic factors. Gene knockout refers to the removal or inactivation of a gene, which can reveal the function of that gene.

Question 6

Which of the following statements regarding the similarity of IQ between twins is FALSE?

Accepted Answer

This statement is false. The correlation for identical twins raised apart is higher than fraternal twins raised together, not the other way around.

Question 7

Twin studies have consistently revealed that the factor that accounts for the least amount of variation in personality trait attributes is:

Accepted Answer

Twin studies have consistently shown that genetics play a significant role in personality trait attributes. However, family environment (such as shared experiences and upbringing) accounts for a relatively small amount of variation in personality traits when compared to genetics and non-shared environmental factors such as peer groups and individual experiences. Therefore, option B is the best choice as it represents the factor that accounts for the least amount of variation in personality trait attributes.

Question 8

Based on Hans Eysenck's work on genetic components of personality,research has shown that the personality trait neuroticism is related to increased action of the neurotransmitter _______.

Accepted Answer

Research has shown that the personality trait of neuroticism is related to increased activity of the neurotransmitter serotonin. This is supported by both molecular genetic studies and neuroimaging studies, which have found associations between variations in serotonin receptor genes and brain regions involved in emotional processing, respectively.

Question 9

In general,which statement below best summarizes the outcome of the role of heredity and environment as they affect intelligence:

Accepted Answer

Research suggests that heredity and environment both contribute to intelligence and that they interact in complex ways. Genes provide a foundation or potential for intelligence, but environmental factors such as nutrition, education, and life experiences can influence whether or not that potential is realized. Furthermore, the effects of genes and environment on intelligence are not static and can vary across different stages of development and in different contexts. Therefore, it is most accurate to say that heredity and environment both play a role in determining intelligence, and that they work together in a dynamic and multifaceted way.

Question 10

Which of the following was NOT mentioned as a factor contributing to the differences in personality traits in identical twins?

Accepted Answer

The factors mentioned as contributing to the differences in personality traits in identical twins were genetics, family environment, and social interactions. School experiences were not mentioned as a contributing factor.

Question 11

Keith and Kirk are identical twins who were separated at birth and raised in different parts of the country in different environments.When as adults they were reunited,researchers compared them on several psychological characteristics.Compared to identical twins that have been raised together,Keith and Kirk probably have:

Accepted Answer

The fact that Keith and Kirk were raised in different environments suggests that they would have different environmental influences on their psychological characteristics. Therefore, they are likely to have fewer characteristics in common compared to identical twins that had been raised together.

Question 12

An adoption study examining the heritability of criminal behaviour found that people who had biological parents and adoptive parents who both had criminal records were the most likely to be criminals themselves.This example was presented to demonstrate:

Accepted Answer

The adoption study provides evidence of how both genetic and environmental factors can interact to produce criminal behavior, as individuals with both biological and adoptive parents with criminal histories were the most likely to exhibit criminal behavior themselves.

Question 13

Although genetic factors are considerably important,they appear to account for about a certain percentage of the IQ variation within a group.This percentage ranges from _________________.

Accepted Answer

Genetic factors are estimated to account for about 50 to 70 percent of IQ variation within a group, with the remainder influenced by environmental factors and their interactions with genetic predispositions.

Question 14

The reaction range principle suggests that genetics sets the upper and lower limits for a trait and _________ indicates where in that range a particular trait will fall.

Accepted Answer

The reaction range principle suggests that genetics sets the upper and lower limits for a trait but the specific trait expression within that range is determined by environmental factors.

Question 15

Though presently there is no quantifiable way to determine the reaction ranges of various intelligence-related traits,research on environmental enrichment programs and adoption studies suggest that the ranges could be:

Accepted Answer

Research on environmental enrichment programs and adoption studies suggest that the ranges of intelligence-related traits could be 15 to 20 IQ points.

Question 16

Researchers who believe in the concept of a reaction range are most likely to argue that intelligence is:

Accepted Answer

The concept of a reaction range suggests that genetics provide a range of potential abilities, but the environment plays a critical role in determining where within that range an individual will fall. Therefore, those who believe in this concept are likely to argue that intelligence is the product of the interaction between genetics and the environment.

Question 17

According to the notion of a reaction range for intelligence,if Dean has a reaction range that is equivalent to Shannon's and Shannon has experienced a considerably more enriched environment compared to Dean,who would have a higher intelligence score?

Accepted Answer

The concept of a reaction range for intelligence suggests that while genetic factors set the boundaries (the range) of an individual's intelligence, environmental factors determine where within this range an individual's intelligence will fall. Since Shannon has experienced a more enriched environment compared to Dean, and they have the same reaction range, Shannon would likely have a higher intelligence score due to the positive impact of the enriched environment on her development within that range.

Question 18

If intelligence was completely determined by genetics,then which set of correlations would be the same?

Accepted Answer

The answer of If intelligence was completely determined by genetics,then...

Question 19

Twin studies have found that some psychological traits,such as intelligence,have a notable genetic contribution.This can be concluded from what evidence?

Accepted Answer

The similarity of identical twins raised apart being greater than the similarity of fraternal twins raised apart suggests a genetic contribution to psychological traits. This is because identical twins share 100% of their genes, while fraternal twins share only 50% on average. Therefore, if identical twins are more similar than fraternal twins, it suggests that genetics play a role in the development of those traits.

Question 20

An adoption study examined the heritability of criminal behaviour in boys adopted at a young age.The level of boys' criminality was greatest when _______.

Accepted Answer

The study found that the level of boys' criminality was greatest when both biological and adoptive fathers had criminal records, meaning that there is a strong hereditary component to criminal behavior. When neither biological nor adoptive fathers had criminal records, the level of boys' criminality was lowest, indicating that environmental factors play a significant role. When only biological fathers had criminal records or only adoptive fathers had criminal records, the level of boys' criminality fell in between these two extremes.

Quiz 4: Genes, Evolution, and Behaviour