Psychology Quiz: Genetics And Environment
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Genetics And EnvironmentQuestion 1 of 20

A couple, both accomplished musicians, raise their child in a home filled with musical instruments, frequent concerts, and constant musical discussion. The child, who has likely inherited some of their parents' genetic aptitude for music, goes on to become a talented musician as well. The influence of the home environment in this case is an example of:

an evocative gene-environment correlation.
a passive gene-environment correlation.
a non-shared environmental factor.
a gene-environment interaction.
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Psychology Quiz

Psychology Quiz: Genetics And Environment

Practice Genetics And Environment in Psychology with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Genetics And Environment, giving you a quick way to practice the rules, question types, and explanations that matter most for Psychology.

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Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

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Question 1

A couple, both accomplished musicians, raise their child in a home filled with musical instruments, frequent concerts, and constant musical discussion. The child, who has likely inherited some of their parents' genetic aptitude for music, goes on to become a talented musician as well. The influence of the home environment in this case is an example of:

  1. an evocative gene-environment correlation.
  2. a passive gene-environment correlation. (correct answer)
  3. a non-shared environmental factor.
  4. a gene-environment interaction.
Explanation: The correct answer is B. Passive gene-environment correlation occurs when children receive genotypes correlated with their family environment. In this case, the parents provide both genes that may predispose the child to musical talent and an environment that fosters the development of that talent. The child does not have to do anything to receive this environment; it is provided 'passively.' A is incorrect because evocative rGE would involve the child's innate talent eliciting special treatment. C is incorrect because the home environment is a shared factor for siblings. D is incorrect because this describes a correlation between genotype and environment, not an interaction where the gene's effect would differ in another environment.

Question 2

Researchers find that individuals with a specific allele for a serotonin transporter gene (5-HTTLPR) are significantly more likely to develop major depression only if they have experienced multiple stressful life events. Individuals with the same allele who have not experienced such events show rates of depression similar to the general population. This finding is a classic example of:

  1. a passive gene-environment correlation, where parents provide both genes for depression and a stressful environment.
  2. a gene-environment interaction, where the effect of a gene on a phenotype depends on a specific environment. (correct answer)
  3. high heritability for depression, which proves that the disorder is primarily genetic in origin.
  4. an evocative gene-environment correlation, where a genetic predisposition for depression elicits stress from others.
Explanation: The correct answer is B. This scenario is a textbook example of a gene-environment interaction (GxE), specifically the diathesis-stress model. The genetic variant (diathesis) creates a vulnerability that is only expressed in the presence of an environmental trigger (stress). The effect of the gene is conditional on the environment. A is incorrect because passive gene-environment correlation (rGE) involves receiving correlated genes and environment from parents, which is not what is described. C is incorrect because while the finding points to a genetic contribution, it does not provide enough information to calculate heritability, and the key concept illustrated is the interaction itself. D is incorrect because evocative rGE is when a person's traits elicit responses from the environment; the scenario describes the environment acting on the person's genetic vulnerability.

Question 3

A teenager with a genetic predisposition for sensation-seeking consistently chooses to associate with peers who engage in risky behaviors, tries extreme sports, and prefers loud, stimulating social settings. This pattern becomes more pronounced as she moves from childhood to adolescence. This increasing alignment between her genetic tendencies and her chosen environments is best explained by:

  1. an increase in passive gene-environment correlation with age.
  2. a decrease in the heritability of sensation-seeking over time.
  3. the growing influence of active gene-environment correlation. (correct answer)
  4. the onset of a gene-environment interaction during puberty.
Explanation: The correct answer is C. Active gene-environment correlation (niche-picking) is the process by which individuals select or create environments that align with their genetic predispositions. The influence of this process increases with age as individuals gain more autonomy to choose their own friends, activities, and lifestyles. A is incorrect because the influence of passive rGE (where parents provide both genes and environment) decreases with age. B is incorrect because the heritability of many traits actually increases with age, partly due to the cumulative effects of active rGE. D is incorrect because the process described is one of environmental selection (correlation), not environmental moderation of genetic effects (interaction).

Question 4

A baby with a genetically influenced 'easy' temperament tends to smile and coo frequently. In response, her caregivers spend more time holding, cuddling, and talking to her than they do with less responsive infants. This increased social stimulation, in turn, fosters her social and emotional development. The process described here is best termed:

  1. active gene-environment correlation.
  2. epigenetic modification.
  3. passive gene-environment correlation.
  4. evocative gene-environment correlation. (correct answer)
Explanation: The correct answer is D. Evocative (or reactive) gene-environment correlation occurs when an individual's genetically influenced traits elicit or evoke specific responses from the environment. Here, the baby's 'easy' temperament (a genetically influenced trait) evokes more nurturing responses from her caregivers. A is incorrect because active rGE involves the individual actively seeking out an environment. B is incorrect because while epigenetic changes might be a result of this process, the psychosocial mechanism described is evocative rGE. C is incorrect because passive rGE involves the parents providing both genes and environment, independent of the child's behavior.

Question 5

An intellectually curious child constantly begs her parents to take her to the library and science museum. The parents, seeing her interest, enroll her in advanced science camps and buy her challenging books. This cycle reinforces her intellectual development over time. This scenario best illustrates which concept?

  1. Passive gene-environment correlation
  2. Evocative gene-environment correlation
  3. Active gene-environment correlation (correct answer)
  4. Gene-environment interaction
Explanation: The correct answer is C. Active gene-environment correlation, also known as niche-picking, occurs when an individual's genetic predispositions lead them to select and create environments that are compatible with those predispositions. In this case, the child's genetically influenced curiosity leads her to actively seek out intellectually stimulating environments. A is incorrect because passive rGE would involve the parents providing a stimulating environment based on their own interests, without the child actively seeking it. B is incorrect because evocative rGE would involve the child's innate traits eliciting a response from others without her active seeking. D is incorrect because the scenario describes a correlation between genotype and environmental exposure, not an interaction where the effect of a gene differs across environments.

Question 6

Imagine a society that successfully creates a uniform and optimal educational environment for all its children, completely eliminating disparities in school quality, teacher training, and learning resources. In this society, what would be the most likely effect on the heritability of academic achievement?

  1. Heritability would decrease to zero, as the environment would now account for all the variance in achievement.
  2. Heritability would increase, because as environmental variance decreases, the proportion of remaining variance due to genes becomes larger. (correct answer)
  3. Heritability would remain unchanged, as the genetic contributions to academic achievement are constant across environments.
  4. It would be impossible to determine the effect, as heritability cannot be calculated in an environmentally uniform population.
Explanation: The correct answer is B. Heritability is the ratio of genetic variance to total phenotypic variance (h2=VG/VPh^2 = V_G / V_P), where VP=VG+VEV_P = V_G + V_E. If the environment is made uniform, the variance attributable to environment (VEV_E) decreases, approaching zero. As VEV_E shrinks, the denominator (VPV_P) gets smaller, and the heritability fraction (h2h^2) gets larger, approaching 1.0. Paradoxically, making the environment more equal for everyone means that the remaining differences between people are more likely to be due to their genetic differences. A is incorrect; the opposite is true. C is incorrect because heritability is a ratio that changes when its components change. D is incorrect; this is a classic thought experiment in behavior genetics.

Question 7

Which of the following scenarios provides the clearest example of a gene-environment interaction (GxE) rather than a gene-environment correlation (rGE)?

  1. A particular allele is associated with a heightened risk of anxiety, but only in individuals who experienced childhood trauma. (correct answer)
  2. A sociable and outgoing toddler receives more smiles and positive attention from his preschool teachers than his shy peers do.
  3. A musically gifted child's parents, who are also musicians, provide her with extensive musical training from a young age.
  4. An intelligent adolescent seeks out intellectually challenging courses and befriends peers who are also academically oriented.
Explanation: Gene-environment interactions and correlations are fundamental concepts in behavioral genetics that students often confuse. The key distinction is that interactions (GxE) occur when genes and environment work together to produce an outcome—the effect of genes depends on the environment, or vice versa. Correlations (rGE) happen when genes and environment are simply associated because people's genetic makeup influences the environments they encounter or create. Option A demonstrates a clear gene-environment interaction because the genetic risk factor (the anxiety-related allele) only produces its effect under specific environmental conditions (childhood trauma). Without the trauma, the allele doesn't increase anxiety risk—the gene's impact is conditional on the environment. Options B, C, and D all illustrate gene-environment correlations instead. In B, the child's genetic temperament (sociability) elicits specific responses from teachers, creating a correlation between genes and social environment. Option C shows how parents pass on both genes for musical ability and provide a musical environment, creating a passive correlation. Option D demonstrates an active correlation where the adolescent's genetic predisposition for intelligence drives them to seek out stimulating environments. Remember this distinction: GxE interactions ask "Does this gene matter differently depending on the environment?" while rGE correlations ask "Do genes influence which environments people experience?" Look for conditional relationships—where genetic effects depend on environmental triggers—to identify true gene-environment interactions on psychology exams.

Question 8

A study of obsessive-compulsive disorder (OCD) finds a concordance rate of 65% for monozygotic (MZ) twins and 20% for dizygotic (DZ) twins. What is the most appropriate conclusion to draw from these findings?

  1. Environmental factors are more influential than genetic factors in the development of OCD.
  2. OCD is entirely caused by genetic factors, with some individuals having incomplete penetrance.
  3. There is a significant genetic component to OCD, but non-shared environmental factors also play a crucial role. (correct answer)
  4. Shared environmental factors are the primary cause of similarity between twins with respect to OCD.
Explanation: The correct answer is C. The fact that the concordance rate for MZ twins (65%), who share 100% of their genes, is much higher than for DZ twins (20%), who share about 50% of their genes, indicates a significant genetic influence. However, because the MZ concordance rate is not 100%, it means that genetics alone cannot explain the outcome. The remaining discordance must be due to non-shared environmental factors or stochastic biological events. A is incorrect because the large difference between MZ and DZ rates points to a strong genetic effect. B is incorrect because a 65% concordance rate rules out a purely genetic cause. D is incorrect because if shared environment were the primary factor, the DZ rate would be much closer to the MZ rate.

Question 9

An adoption study on adult antisocial behavior finds a correlation of +0.40 between adopted individuals and their biological parents, and a correlation of +0.10 between the same adopted individuals and their adoptive parents. Which interpretation is most consistent with these results?

  1. The shared family environment provided by adoptive parents has a stronger influence on antisocial behavior than genetic inheritance.
  2. Genetic factors have a substantial influence on antisocial behavior, while the shared family environment has a weaker influence. (correct answer)
  3. Antisocial behavior is primarily learned from biological parents before adoption, negating any genetic influence.
  4. There is a strong gene-environment interaction, where the adoptive environment determines the expression of genes from biological parents.
Explanation: The correct answer is B. In an adoption study design, the correlation with biological parents (who provide genes but no rearing environment) reflects genetic influences, while the correlation with adoptive parents (who provide the rearing environment but no genes) reflects shared environmental influences. Since the correlation with biological parents (+0.40) is substantially higher than with adoptive parents (+0.10), this suggests a larger role for genetic factors in influencing antisocial behavior. A is incorrect because the data show the opposite. C is an implausible explanation that misinterprets the meaning of the correlation. D describes a gene-environment interaction, which cannot be directly inferred from these two correlations alone; the data are more direct evidence for the main effects of genes and environment.

Question 10

A researcher identifies a gene variant that is associated with heightened emotional sensitivity. Children with this variant who are raised in supportive, positive environments become exceptionally prosocial and empathetic. However, children with the same variant who are raised in harsh, negative environments are at high risk for emotional dysregulation and aggression. This pattern, where the gene amplifies the effect of both positive and negative environments, is best described as:

  1. the diathesis-stress model.
  2. passive gene-environment correlation.
  3. differential susceptibility. (correct answer)
  4. canalization.
Explanation: The correct answer is C. This scenario describes differential susceptibility (also known as the 'orchids and dandelions' hypothesis). This model posits that certain genetic markers make individuals more susceptible to environmental influences in general, both for better (in positive environments) and for worse (in negative environments). A is incorrect because the diathesis-stress model focuses only on the negative outcome: a genetic vulnerability (diathesis) that is triggered by stress. It does not account for the enhanced positive outcomes in supportive environments. B is incorrect as it refers to the correlation between genes and environment, not an interaction. D, canalization, is the opposite concept, referring to a developmental pathway that is resistant to environmental perturbation.

Question 11

Suppose the heritability of reading ability is found to be high (e.g., h2=0.70h^2 = 0.70) within both a high-income population and a low-income population. However, the average reading ability score is significantly lower in the low-income population. What can be concluded about the cause of the average difference in reading ability between the two groups?

  1. The difference between the groups is most likely due to genetic differences, as the trait is highly heritable in both.
  2. The high heritability within each group indicates that environmental factors, such as school quality, cannot explain the difference between them.
  3. Within-group heritability estimates provide no information about the cause of between-group differences in average scores. (correct answer)
  4. The difference between the groups must be due to a gene-environment interaction specific to the low-income group.
Explanation: The correct answer is C. This is a critical point about heritability. A heritability estimate explains the proportion of variance within a specific population at a specific time. It provides no information about the cause of average differences between populations, especially when those populations experience systematically different environments (e.g., differences in nutrition, resources, school quality). The 'seeds in different soil' analogy applies here: even if height is highly heritable within a plot of well-fertilized soil and within a plot of poorly-fertilized soil, the average height difference between the plots is due to the soil (environment). A is the most common and serious misinterpretation of heritability. B is incorrect because environmental factors that differ between groups are a very likely cause of the average difference. D is a possibility but not a necessary conclusion; the core issue is that heritability is uninformative for this question.

Question 12

A couple, both accomplished musicians, raise their child in a home filled with musical instruments, frequent concerts, and constant musical discussion. The child, who has likely inherited some of their parents' genetic aptitude for music, goes on to become a talented musician as well. The influence of the home environment in this case is an example of:

  1. an evocative gene-environment correlation.
  2. a passive gene-environment correlation. (correct answer)
  3. a non-shared environmental factor.
  4. a gene-environment interaction.
Explanation: The correct answer is B. Passive gene-environment correlation occurs when children receive genotypes correlated with their family environment. In this case, the parents provide both genes that may predispose the child to musical talent and an environment that fosters the development of that talent. The child does not have to do anything to receive this environment; it is provided 'passively.' A is incorrect because evocative rGE would involve the child's innate talent eliciting special treatment. C is incorrect because the home environment is a shared factor for siblings. D is incorrect because this describes a correlation between genotype and environment, not an interaction where the gene's effect would differ in another environment.

Question 13

Researchers in Finland in the 1990s calculated the heritability of educational attainment to be approximately 0.65. If a similar study were conducted today in a developing nation with vastly unequal access to education, what would be the most likely finding regarding the heritability of educational attainment in that nation?

  1. The heritability estimate would be even higher, as genetic potential becomes more important when resources are scarce.
  2. It is impossible to calculate heritability in a population with environmental inequality, so no estimate could be produced.
  3. The heritability estimate would be identical, as heritability is a fixed biological constant for a given trait.
  4. The heritability estimate would be significantly lower, because environmental variation has a much larger impact on outcomes. (correct answer)
Explanation: When you encounter heritability questions, remember that heritability estimates are not fixed biological constants—they depend heavily on the specific population and environmental conditions being studied. Heritability measures how much of the variation in a trait within a population is due to genetic differences versus environmental differences. Finland in the 1990s had relatively equal access to quality education, meaning environmental factors were fairly consistent across the population. In such conditions, genetic differences become a larger source of variation in educational outcomes, leading to higher heritability estimates like 0.65. In a developing nation with vastly unequal educational access, environmental factors would create enormous variation in outcomes. Some children might have no schooling while others attend excellent schools. This dramatic environmental variation would overshadow genetic contributions, making heritability estimates significantly lower. Answer D correctly identifies this inverse relationship between environmental inequality and heritability. Answer A incorrectly assumes genetic potential becomes more important when resources are scarce—actually, resource scarcity increases environmental variation's impact. Answer B is wrong because heritability can absolutely be calculated in unequal populations; the calculation simply reflects the high environmental variation present. Answer C represents a fundamental misconception that heritability is biologically fixed, when it actually varies dramatically across different populations and contexts. Remember this key principle: heritability estimates are higher in more equal environments and lower in unequal environments. When you see heritability questions comparing different societies or time periods, always consider how environmental variation differs between them.

Question 14

A longitudinal study investigates the link between a polymorphism of the DRD4 gene, associated with novelty-seeking, and the development of adolescent conduct problems. The study finds a strong positive association, but only for adolescents living in neighborhoods with high levels of disorganization and low collective efficacy. For those in organized, supportive neighborhoods, the gene variant has no association with conduct problems. This finding best supports which principle?

  1. The DRD4 gene has a direct, causal effect on conduct problems, which is masked by protective environments.
  2. Neighborhood disorganization causes a mutation in the DRD4 gene, leading to conduct problems.
  3. Adolescents with the DRD4 polymorphism actively choose to live in disorganized neighborhoods.
  4. The influence of the DRD4 gene polymorphism on conduct problems is moderated by the social environment. (correct answer)
Explanation: When you encounter questions about genetic influences on behavior, look for whether the study shows a direct effect or an interaction with environmental factors. Gene-environment interactions are fundamental to understanding how genetics actually influence psychological outcomes. This study demonstrates a classic gene-environment interaction. The DRD4 polymorphism only predicts conduct problems when combined with disorganized neighborhoods - it has no effect in supportive environments. This pattern shows that the gene's influence is moderated by social context, meaning the environmental factor changes the strength or direction of the genetic effect. Answer D correctly identifies this moderation pattern. Answer A incorrectly suggests the gene has a direct causal effect that's simply "masked" by good environments. But the data shows no relationship at all in supportive neighborhoods, not a masked one. Answer B reverses causation entirely - environments don't cause genetic mutations. The DRD4 polymorphism exists before environmental exposure. Answer C proposes gene-environment correlation (people choosing environments based on their genetics), but the study examined neighborhood effects on adolescents who typically don't choose where they live. The key insight is recognizing moderation versus main effects. A main effect would show the gene predicting conduct problems regardless of environment. Moderation means the effect depends on context - exactly what this study found. When studying behavioral genetics, remember that most genetic influences on complex behaviors work through interactions with environmental factors, not as simple direct effects.

Question 15

A 20-year longitudinal study followed two groups of children: one group with a genetic predisposition for impulsivity and one group without. Within each group, children were raised in either high-conflict or low-conflict family environments. The study found that children with the genetic predisposition raised in high-conflict homes had significantly higher rates of delinquency than any other group. The same children raised in low-conflict homes had delinquency rates similar to children without the predisposition. Furthermore, children without the predisposition showed only a very small increase in delinquency when raised in high-conflict versus low-conflict homes.

The results of this study most strongly suggest that:

  1. the genetic predisposition and the family environment interact to predict delinquency. (correct answer)
  2. high-conflict home environments are the sole cause of delinquency for all children.
  3. the genetic predisposition for impulsivity is the sole determinant of delinquency.
  4. passive gene-environment correlation fully explains the development of delinquency.
Explanation: When you encounter psychology research describing different groups with varying genetic and environmental factors, you're likely dealing with gene-environment interaction concepts. Pay attention to how outcomes change when both factors are present versus absent. This study demonstrates a classic gene-environment interaction because the genetic predisposition for impulsivity only leads to significantly higher delinquency rates when combined with a high-conflict environment. The key evidence is that genetically predisposed children in low-conflict homes showed normal delinquency rates, while the same genetic group in high-conflict homes showed dramatically elevated rates. This means neither factor alone determines the outcome—they must work together. Answer A correctly identifies this interaction pattern where genetic vulnerability requires environmental stress to manifest problematic behavior. Answer B is wrong because children without genetic predisposition showed only minimal increases in delinquency even in high-conflict homes, proving environment alone isn't the sole cause. Answer C is incorrect because genetic predisposition by itself (in low-conflict homes) didn't increase delinquency rates. Answer D misunderstands the concept—passive gene-environment correlation refers to parents providing both genes and environment that match those genes, but this study specifically manipulated environmental conditions across genetic groups. When studying developmental psychology, remember that gene-environment interactions follow this pattern: genetic risk + environmental stress = amplified problems, but genetic risk + supportive environment = normal outcomes. Look for research designs that cross genetic factors with environmental conditions to identify true interactions versus simple additive effects.

Question 16

A new body of research robustly demonstrates that a specific genetic variant significantly increases the risk for developing learning disabilities, but only among children who experience poor nutrition in early childhood. Which policy intervention is most logically supported by this gene-environment interaction finding?

  1. Implementing a universal early childhood nutrition program to mitigate the risk for all children. (correct answer)
  2. Focusing educational resources exclusively on children with the genetic variant, as others are not at risk.
  3. Genetic screening for all newborns to identify at-risk individuals for placement in specialized education programs.
  4. Concluding that learning disabilities are primarily a nutritional issue and that genetic research is irrelevant to policy.
Explanation: When you encounter questions about gene-environment interactions, remember that these findings reveal how genetic and environmental factors work together—neither operates in isolation. This research shows that the genetic variant only increases learning disability risk when combined with poor early nutrition, demonstrating a classic gene-environment interaction. Answer A is correct because a universal early childhood nutrition program addresses the environmental trigger (poor nutrition) that activates the genetic risk. Since we can't change genetics but can modify environmental conditions, ensuring good nutrition for all children would prevent the gene-environment interaction from occurring, protecting even genetically vulnerable children. Answer B misunderstands the interaction—children without the genetic variant aren't completely risk-free, and more importantly, this approach ignores that we can prevent the risk entirely through environmental intervention. Answer C focuses on genetic screening and specialized education after problems develop, rather than prevention through addressing the environmental trigger. This reactive approach misses the key insight that good nutrition could prevent the learning disabilities from developing in the first place. Answer D incorrectly dismisses genetic factors entirely, failing to recognize that this is specifically about gene-environment interaction rather than nutrition alone causing learning disabilities. The takeaway for psychology exams: when you see gene-environment interaction research, look for policy solutions that modify the environmental component rather than trying to change genetics or ignoring one factor entirely. Prevention through environmental intervention is typically more effective and feasible than reactive approaches.

Question 17

A specific gene variant is linked to increased risk-taking behavior. In a stable, predictable environment with abundant resources, this trait is maladaptive and associated with poor outcomes. However, in a volatile, resource-scarce environment, the same trait is associated with greater success in acquiring mates and resources. This context-dependent fitness illustrates which core concept?

  1. Genetic drift is the primary driver of the frequency of the risk-taking allele in different populations.
  2. All genetic variants associated with behavior are eventually eliminated by natural selection if they are maladaptive in any context.
  3. Risk-taking behavior is a purely learned strategy that is independent of any genetic predisposition.
  4. The adaptiveness of a genetically influenced trait is often dependent on the specific ecological or social environment. (correct answer)
Explanation: This question tests your understanding of gene-environment interactions and evolutionary psychology principles. When you encounter scenarios describing how the same trait produces different outcomes in different environments, think about how natural selection operates contextually rather than absolutely. The scenario perfectly illustrates that genetic predispositions don't exist in a vacuum—their adaptive value depends entirely on environmental context. In stable environments, risk-taking leads to poor outcomes because unnecessary risks waste resources and threaten survival. But in volatile, scarce conditions, risk-taking becomes advantageous because conservative strategies won't secure enough resources for survival and reproduction. This demonstrates that the same genetic variant can be adaptive or maladaptive depending on circumstances, making D correct. Option A incorrectly focuses on genetic drift, which refers to random changes in allele frequency—but this scenario describes systematic selection pressures, not random processes. Option B represents a common misconception that any trait showing maladaptive effects will be eliminated. This ignores how environmental variation maintains genetic diversity and how traits can be adaptive in some contexts while maladaptive in others. Option C dismisses genetic influence entirely, contradicting the premise that discusses a specific gene variant linked to the behavior. Remember that evolutionary psychology questions often test whether you understand that "adaptive" isn't absolute—it's always relative to specific environmental conditions. When you see traits that seem contradictory in their effects, look for the environmental factors that determine when each effect occurs.

Question 18

A 20-year longitudinal study followed two groups of children: one group with a genetic predisposition for impulsivity and one group without. Within each group, children were raised in either high-conflict or low-conflict family environments. The study found that children with the genetic predisposition raised in high-conflict homes had significantly higher rates of delinquency than any other group. The same children raised in low-conflict homes had delinquency rates similar to children without the predisposition. Furthermore, children without the predisposition showed only a very small increase in delinquency when raised in high-conflict versus low-conflict homes.

The results of this study most strongly suggest that:

  1. the genetic predisposition and the family environment interact to predict delinquency. (correct answer)
  2. high-conflict home environments are the sole cause of delinquency for all children.
  3. the genetic predisposition for impulsivity is the sole determinant of delinquency.
  4. passive gene-environment correlation fully explains the development of delinquency.
Explanation: When you encounter psychology research describing different groups with varying genetic and environmental factors, you're likely dealing with gene-environment interaction concepts. Pay attention to how outcomes change when both factors are present versus absent. This study demonstrates a classic gene-environment interaction because the genetic predisposition for impulsivity only leads to significantly higher delinquency rates when combined with a high-conflict environment. The key evidence is that genetically predisposed children in low-conflict homes showed normal delinquency rates, while the same genetic group in high-conflict homes showed dramatically elevated rates. This means neither factor alone determines the outcome—they must work together. Answer A correctly identifies this interaction pattern where genetic vulnerability requires environmental stress to manifest problematic behavior. Answer B is wrong because children without genetic predisposition showed only minimal increases in delinquency even in high-conflict homes, proving environment alone isn't the sole cause. Answer C is incorrect because genetic predisposition by itself (in low-conflict homes) didn't increase delinquency rates. Answer D misunderstands the concept—passive gene-environment correlation refers to parents providing both genes and environment that match those genes, but this study specifically manipulated environmental conditions across genetic groups. When studying developmental psychology, remember that gene-environment interactions follow this pattern: genetic risk + environmental stress = amplified problems, but genetic risk + supportive environment = normal outcomes. Look for research designs that cross genetic factors with environmental conditions to identify true interactions versus simple additive effects.

Question 19

Researchers find that individuals with a specific allele for a serotonin transporter gene (5-HTTLPR) are significantly more likely to develop major depression only if they have experienced multiple stressful life events. Individuals with the same allele who have not experienced such events show rates of depression similar to the general population. This finding is a classic example of:

  1. a passive gene-environment correlation, where parents provide both genes for depression and a stressful environment.
  2. a gene-environment interaction, where the effect of a gene on a phenotype depends on a specific environment. (correct answer)
  3. high heritability for depression, which proves that the disorder is primarily genetic in origin.
  4. an evocative gene-environment correlation, where a genetic predisposition for depression elicits stress from others.
Explanation: The correct answer is B. This scenario is a textbook example of a gene-environment interaction (GxE), specifically the diathesis-stress model. The genetic variant (diathesis) creates a vulnerability that is only expressed in the presence of an environmental trigger (stress). The effect of the gene is conditional on the environment. A is incorrect because passive gene-environment correlation (rGE) involves receiving correlated genes and environment from parents, which is not what is described. C is incorrect because while the finding points to a genetic contribution, it does not provide enough information to calculate heritability, and the key concept illustrated is the interaction itself. D is incorrect because evocative rGE is when a person's traits elicit responses from the environment; the scenario describes the environment acting on the person's genetic vulnerability.

Question 20

An adoption study on adult antisocial behavior finds a correlation of +0.40 between adopted individuals and their biological parents, and a correlation of +0.10 between the same adopted individuals and their adoptive parents. Which interpretation is most consistent with these results?

  1. The shared family environment provided by adoptive parents has a stronger influence on antisocial behavior than genetic inheritance.
  2. Genetic factors have a substantial influence on antisocial behavior, while the shared family environment has a weaker influence. (correct answer)
  3. Antisocial behavior is primarily learned from biological parents before adoption, negating any genetic influence.
  4. There is a strong gene-environment interaction, where the adoptive environment determines the expression of genes from biological parents.
Explanation: The correct answer is B. In an adoption study design, the correlation with biological parents (who provide genes but no rearing environment) reflects genetic influences, while the correlation with adoptive parents (who provide the rearing environment but no genes) reflects shared environmental influences. Since the correlation with biological parents (+0.40) is substantially higher than with adoptive parents (+0.10), this suggests a larger role for genetic factors in influencing antisocial behavior. A is incorrect because the data show the opposite. C is an implausible explanation that misinterprets the meaning of the correlation. D describes a gene-environment interaction, which cannot be directly inferred from these two correlations alone; the data are more direct evidence for the main effects of genes and environment.