MCAT Psychological Social Foundations Quiz: 7a Behavioral Genetics Gene Environment

19 questions · exam conditions

0:00

7a Behavioral Genetics Gene EnvironmentQuestion 1 of 19

A study examined gene–environment correlation in sports participation. Adolescents were genotyped for a variant associated with higher endurance capacity. The school offered multiple sports with open tryouts and no fees. Researchers found that students with the endurance-associated genotype were more likely to join cross-country or soccer rather than non-endurance clubs, and they reported enjoying long-duration exercise more. Participation predicted improved cardiovascular fitness at follow-up. The authors noted that genetic differences may have influenced selection into certain activities, increasing exposure to training environments.

What prediction is most consistent with gene-environment correlation as described?

Fitness gains should occur only for students without the endurance-associated genotype.

Training should alter the DNA sequence of the endurance gene, producing the endurance-associated genotype.

Enjoyment of endurance exercise should be unrelated to genotype because preferences are purely environmental.

If sports participation is assigned randomly, genotype differences in the types of activities chosen should decrease.

← Back to quizzes

MCAT Psychological Social Foundations Quiz

MCAT Psychological Social Foundations Quiz: 7a Behavioral Genetics Gene Environment

Practice 7a Behavioral Genetics Gene Environment in MCAT Psychological Social Foundations 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 7a Behavioral Genetics Gene Environment, giving you a quick way to practice the rules, question types, and explanations that matter most for MCAT Psychological Social Foundations.

How to use this quiz

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.

All questions

Question 1

What prediction is most consistent with gene-environment correlation as described?

Fitness gains should occur only for students without the endurance-associated genotype.
Training should alter the DNA sequence of the endurance gene, producing the endurance-associated genotype.
Enjoyment of endurance exercise should be unrelated to genotype because preferences are purely environmental.
If sports participation is assigned randomly, genotype differences in the types of activities chosen should decrease. (correct answer)

Explanation: This question evaluates gene–environment correlation in behavioral genetics, where genotypes influence sports selection. Active correlation involves choosing matching activities, enhancing fitness. The vignette links endurance genotype to specific sports. Choice D predicts decreased differences with random assignment. Choice B suggests genotype change from training. Test via forced participation. Differentiate by selection mechanisms.

Question 2

Researchers conducted a twin study on language development in bilingual homes. Monozygotic (MZ) and dizygotic (DZ) twins were assessed at age 5 on vocabulary in the community language. Some families used a bilingual environment at home (regular use of two languages), while others used only the community language. In monolingual homes, MZ twins were more similar than DZ twins in vocabulary. In bilingual homes, average vocabulary in the community language was slightly lower, and MZ–DZ differences in similarity were smaller. The authors suggested the language environment altered the extent to which genetic differences explained variability in vocabulary.

Based on the vignette, which conclusion about genetic predisposition and environment is supported?

The bilingual home environment may reduce the relative impact of genetic differences on community-language vocabulary. (correct answer)
Lower average vocabulary in bilingual homes proves genes are irrelevant to language development.
Smaller MZ–DZ differences in bilingual homes show that twins' genes have changed due to language exposure.
Because twins share a household, vocabulary differences must be caused only by measurement error.

Explanation: This question assesses gene–environment interaction in behavioral genetics using twins, with bilingualism moderating vocabulary heritability. Bilingual environments can attenuate genetic differences in language. The vignette indicates smaller MZ–DZ gaps in bilingual homes. Choice A supports reduced genetic impact. Choice B overclaims irrelevance of genes. Compare similarities by language exposure. Interactions alter heritability contexts.

Question 3

Researchers conducted a twin study on social media use and body dissatisfaction. Monozygotic (MZ) and dizygotic (DZ) twin pairs were surveyed at age 17. Some attended schools with a strict phone-free policy during the school day, while others attended schools without such restrictions. In unrestricted schools, MZ twins were noticeably more similar than DZ twins in body dissatisfaction scores. In phone-restricted schools, average body dissatisfaction was lower, and MZ–DZ differences in similarity were smaller. The authors argued that limiting exposure reduced the extent to which genetic differences in susceptibility were expressed.

Based on the vignette, which conclusion about genetic predisposition and environment is supported?

Phone restriction may dampen the expression of genetic susceptibility to body dissatisfaction. (correct answer)
Phone restriction proves body dissatisfaction is caused entirely by school policy rather than genes.
Greater MZ similarity in unrestricted schools indicates that environment plays no role in body dissatisfaction.
School phone policies change twins' zygosity classification over time.

Explanation: This question evaluates gene–environment interaction in behavioral genetics via twins, showing phone restrictions moderate body dissatisfaction heritability. Environmental limits can attenuate genetic expression, reducing twin similarity differences. The vignette illustrates smaller MZ–DZ gaps in restricted schools with lower dissatisfaction. Choice A supports this, indicating restrictions dampen genetic susceptibility. Choice B is a distractor, overclaiming environmental causation by ignoring genetic roles. For similar items, compare heritability estimates across conditions. Remember, interactions appear when protective environments shrink genetic variance.

Question 4

A study explored gene–environment correlation in risk-taking. Young adults were genotyped for a variant associated with higher sensation seeking. Participants reported their typical weekend activities and peer networks. Individuals with the sensation-seeking–associated genotype were more likely to report friends who enjoyed high-adrenaline activities (e.g., cliff diving) and were more likely to attend events where alcohol was present. The study noted that genetic predispositions may shape the social environments people select, which in turn influence risk-taking outcomes.

What prediction is most consistent with gene-environment correlation as described?

Risk-taking should occur only among individuals without the sensation-seeking–associated genotype.
Attending alcohol-present events should change participants' genotype toward lower sensation seeking.
Genotype should be unrelated to peer networks because peers are entirely determined by chance.
If access to high-adrenaline activities is restricted for everyone, genotype differences in exposure to those settings should decrease. (correct answer)

Explanation: This question examines gene–environment correlation in behavioral genetics, where sensation seeking shapes social environments. Correlation involves selecting risk-aligned peers and activities. The vignette links genotype to high-adrenaline friends and events. Choice D predicts decreased differences with restrictions. Choice B suggests event changes genotype. Predict under restricted access. Identify if predispositions drive selection.

Question 5

A longitudinal study explored gene–environment correlation in musical training. Children were genotyped for a polygenic score associated with rhythmic perception. Families were offered subsidized music lessons, but enrollment required parents to sign up and bring the child weekly. Researchers found that children with higher rhythmic-perception scores were more likely to request lessons, and their parents reported more frequent attendance at live music events. After a year, lesson attendance predicted improved rhythm tests. The authors noted that genetic differences may have influenced exposure to music-rich environments through both child preference and parental behavior.

What prediction is most consistent with gene-environment correlation as described?

Parents' attendance at music events should be unrelated to children's rhythmic-perception scores.
Children's polygenic scores should increase after a year of lessons, reflecting environmental enhancement of DNA.
Lesson attendance should predict improvement only among children with low rhythmic-perception scores.
If all children are automatically enrolled and transported to lessons, genotype differences in lesson exposure should shrink. (correct answer)

Explanation: This question assesses gene–environment correlation in behavioral genetics, where polygenic scores influence access to musical enrichment. Passive and active correlations occur when genes affect parental provision or child selection of environments. The vignette links higher scores to requested lessons and home enrichment. Choice D is correct, predicting reduced differences with automatic enrollment, disrupting correlation. Choice B distracts by implying environments change scores, reversing causality. Test by altering voluntariness in predictions. Strategy: identify correlation if genes predict environmental exposure.

Question 6

Investigators examined epigenetic signatures of chronic loneliness. Adults completed a loneliness scale and were categorized as persistently high or persistently low loneliness across three assessments in one year. Blood samples were analyzed for methylation at regulatory regions near an immune-related gene, and inflammatory markers were measured. The high-loneliness group showed higher methylation at one regulatory region and higher inflammation; DNA sequencing showed no systematic differences between groups. The authors suggested that a social experience may be associated with altered gene expression regulation.

Which finding is most consistent with the vignette's discussion of epigenetics?

Persistent loneliness is associated with differences in methylation near an immune gene without changes in DNA sequence. (correct answer)
Loneliness causes individuals to inherit different immune alleles from their parents during adulthood.
Higher methylation implies the immune gene's nucleotide sequence must differ between groups.
Because loneliness is subjective, it cannot be associated with biological differences.

Explanation: This question explores gene–environment interaction through epigenetics in behavioral genetics, with loneliness altering immune methylation. Epigenetic changes regulate genes without sequence alteration, linked to social experiences. The vignette shows higher methylation and inflammation in loneliness, no sequence differences. Choice A aligns, highlighting methylation without change. Choice C assumes sequence differences. Verify regulation focus. Epigenetics connects social to biological.

Question 7

A twin study examined how neighborhood resources interact with genetic liability for anxiety. Investigators recruited monozygotic (MZ) and dizygotic (DZ) twin pairs raised together until age 10, then some families moved (due to job relocation) to either a high-resource neighborhood (more parks, lower crime) or a low-resource neighborhood (fewer parks, higher crime). At age 16, anxiety symptoms were assessed. In low-resource neighborhoods, MZ twins were much more similar to each other in anxiety than DZ twins. In high-resource neighborhoods, MZ and DZ similarity was more comparable, and average anxiety was lower. Researchers argued the environment altered the extent to which genetic differences were expressed.

Based on the vignette, which conclusion about genetic predisposition and environment is supported?

High-resource neighborhoods appear to attenuate the expression of genetic liability for anxiety. (correct answer)
Moving to a high-resource neighborhood changes twins' DNA sequence, reducing heritability.
Greater MZ similarity in low-resource neighborhoods proves anxiety is caused only by genes.
DZ twins should be as similar as MZ twins in all environments if anxiety is polygenic.

Explanation: This question assesses knowledge of gene–environment interaction in behavioral genetics, focusing on how neighborhood resources influence the heritability of anxiety. In twin studies, greater MZ than DZ similarity indicates genetic influence, but environmental factors can moderate this heritability, reducing genetic expression in protective settings. The vignette connects this by showing reduced MZ–DZ differences in high-resource neighborhoods, suggesting these environments attenuate genetic liability. Choice A is supported as it reflects how high-resource areas lower average anxiety and minimize genetic differences, consistent with moderated heritability. Choice B is a distractor because it misrepresents interaction as changing DNA sequence rather than expression, a common misconception in epigenetics. For similar questions, compare twin correlations across environments to gauge interaction effects. Always distinguish between heritability estimates and actual genetic changes when evaluating environmental moderation.

Question 8

Researchers used a twin design to study how household chaos interacts with genetic influences on executive function. Monozygotic (MZ) and dizygotic (DZ) twins ages 9–10 completed the same inhibition task. Parents completed a household-chaos inventory (noise, unpredictable routines). In high-chaos homes, MZ twins were much more similar than DZ twins in inhibition performance. In low-chaos homes, MZ and DZ similarity was more comparable and average performance was higher. The authors suggested that calmer environments reduced the extent to which genetic differences accounted for variability.

Based on the vignette, which conclusion about genetic predisposition and environment is supported?

Low household chaos causes DZ twins to become genetically identical to MZ twins.
High household chaos proves inhibition is entirely genetic because MZ twins are similar.
Low household chaos may attenuate genetic differences in inhibition performance. (correct answer)
Because both twin types share a home, environment cannot influence executive function.

Explanation: This question assesses gene–environment interaction in behavioral genetics via twins, with chaos moderating inhibition heritability. Low chaos reduces genetic expression, equalizing twin similarities. The vignette shows comparable MZ–DZ in low-chaos homes. Choice C supports attenuation of differences. Choice B misclaims entirely genetic in chaos. Compare similarities across chaos levels. Interactions appear in varying heritabilities.

Question 9

Investigators explored gene–environment correlation in children's reading development. Children were genotyped for a polygenic score associated with higher verbal aptitude. Without informing teachers of genotypes, researchers observed that children with higher scores were more likely to join an after-school reading club and were also more likely to have parents who reported frequent library visits. The school offered the club to all students at no cost, and enrollment was voluntary. By the end of the year, club participation predicted higher reading comprehension, but the researchers noted that the same genetic factors linked to verbal aptitude may have increased children's likelihood of selecting reading-rich environments.

What prediction is most consistent with gene–environment correlation as described?

If the reading club is mandatory, children's genotypes should become more similar across classrooms over time.
Children with higher verbal polygenic scores should be disproportionately represented in other language-enriching electives when available. (correct answer)
Children's polygenic scores should change after a year of reading club participation, indicating environmental causation.
Reading comprehension gains from the club should occur only in children with low verbal polygenic scores.

Explanation: This question evaluates comprehension of gene–environment correlation in behavioral genetics, where genetic factors influence environmental exposure, such as through active selection of enriching activities. Active gene–environment correlation involves individuals seeking environments that match their genetic predispositions, like high verbal aptitude leading to reading-rich choices. The vignette illustrates this with children having higher polygenic scores more likely to join voluntary reading clubs, correlating genes with environment. Choice B is correct as it predicts disproportionate representation in other electives, aligning with active correlation where genotypes drive selection. Choice C distracts by suggesting environments alter DNA, confusing correlation with causation and ignoring that polygenic scores are stable. In future questions, test for correlation by predicting reduced genotype–environment links under random assignment. A strategy is to differentiate active, passive, and evocative types based on how genes shape exposure.

Question 10

Researchers investigated epigenetics in the context of early-life stress. Newborns were enrolled in a longitudinal study. Some infants experienced high caregiver instability during the first year (multiple primary caregivers due to housing transitions), while others had stable caregiving. At age 8, blood samples were analyzed for DNA methylation patterns near a glucocorticoid receptor gene involved in stress reactivity. Children exposed to early instability showed higher methylation at a regulatory region and, during a lab stress task, exhibited higher cortisol responses than children with stable caregiving. DNA sequencing showed no differences in the gene's coding region between groups. The authors proposed that environmental experience altered gene expression potential without changing the DNA sequence.

Which finding is most consistent with the vignette's discussion of gene–environment interaction?

Children with early instability show altered methylation near a stress-related gene despite identical DNA sequence in that region. (correct answer)
Children with early instability inherit new alleles for the glucocorticoid receptor gene from caregivers.
Cortisol responses fully determine DNA sequence differences between groups by age 8.
Methylation patterns are unrelated to environmental exposure and reflect only random measurement error.

Explanation: This question probes understanding of gene–environment interaction via epigenetics in behavioral genetics, where early stress alters gene expression without changing DNA sequence. Epigenetic modifications like DNA methylation can regulate gene activity, such as increasing stress reactivity through higher methylation near glucocorticoid receptors. The vignette links this to early caregiver instability, showing higher methylation and cortisol in affected children despite identical gene sequences. Choice A is consistent, emphasizing altered methylation without sequence changes, exemplifying epigenetic interaction. Choice B fails as it implies inheritance of new alleles, a misconception that confuses epigenetics with genetic mutation. For verification in similar items, confirm if outcomes involve expression changes rather than sequence alterations. Use this as a check: epigenetics explains environmental impacts on gene function without heritable mutations.

Question 11

Investigators studied epigenetic mechanisms linking diet and stress regulation. Adults enrolled in a 12-week program that either provided consistent access to nutritious meals (delivered weekly) or provided no food support. Participants were not selected based on genotype. At baseline and week 12, researchers measured methylation at regulatory sites near a gene involved in inflammatory signaling and collected self-reports of chronic stress. The food-support group showed decreased methylation at one regulatory site and reported reduced stress; the no-support group showed minimal change. DNA sequencing revealed no differences between groups. The authors suggested that improved nutrition may alter gene expression potential through epigenetic modification.

Which finding is most consistent with the vignette's discussion of gene–environment interaction?

Food support is associated with changes in methylation at a regulatory site without changes in DNA sequence. (correct answer)
Food support causes participants to inherit different alleles for inflammatory genes from their parents.
Methylation changes prove the gene's coding sequence has mutated during the program.
Because participants were not selected by genotype, genes cannot influence stress-related outcomes.

Explanation: This question explores gene–environment interaction through epigenetics in behavioral genetics, linking nutrition to stress gene regulation. Epigenetic changes like reduced methylation can enhance gene expression, potentially lowering stress without altering DNA. The vignette connects food support to decreased methylation and stress, with no sequence differences. Choice A aligns, highlighting methylation shifts without sequence changes, illustrating interaction. Choice C fails by assuming methylation implies mutation, a misconception in epigenetics. For verification, ensure explanations focus on regulation, not sequence. A strategy is to note epigenetics as a mechanism for environmental influence on gene activity.

Question 12

Researchers examined epigenetic changes following exposure to air pollution. Two groups of adults lived for at least 5 years in either high-traffic areas or low-traffic areas within the same city. Groups were matched on age and income. Blood samples were analyzed for histone acetylation patterns near genes involved in oxidative stress response. Participants in high-traffic areas showed lower acetylation at one regulatory region and higher levels of an oxidative stress biomarker; DNA sequencing showed no systematic differences between groups. The authors suggested that chronic environmental exposure may alter gene expression regulation.

Which finding is most consistent with the vignette's discussion of epigenetics?

High-traffic exposure is associated with altered histone acetylation near stress-response genes without changes in DNA sequence. (correct answer)
High-traffic exposure causes new alleles to appear in the oxidative stress genes across adulthood.
Lower acetylation implies the DNA code has been rewritten by pollutants.
Because groups were matched on income, environmental exposure cannot influence gene regulation.

Explanation: This question probes gene–environment interaction via epigenetics in behavioral genetics, with pollution altering stress gene acetylation. Epigenetics involves modifications like histone acetylation affecting expression without DNA changes. The vignette shows lower acetylation and higher stress in high-traffic areas, no sequence differences. Choice A aligns, emphasizing acetylation changes without sequence alteration. Choice C fails, assuming acetylation implies rewriting DNA. Verify by focusing on regulation. Check: epigenetics explains exposure effects on gene function.

Question 13

Researchers compared monozygotic (MZ) and dizygotic (DZ) twins to examine how food marketing exposure interacts with genetic influences on snack consumption. Twin pairs were surveyed at age 12. Some lived in households that restricted screen time and used ad-blocking software; others had no restrictions. In unrestricted households, MZ twins were more similar than DZ twins in daily sugary-snack intake. In restricted households, average intake was lower and MZ–DZ differences in similarity were smaller. The authors argued that limiting exposure reduced the degree to which genetic differences shaped behavior.

Based on the vignette, which conclusion about genetic predisposition and environment is supported?

Restricting marketing exposure may reduce the expression of genetic differences in snack consumption. (correct answer)
Because intake is lower with restrictions, snack consumption must be entirely environmental in origin.
Greater MZ similarity in unrestricted households proves that advertising has no effect.
Ad-blocking changes twins' genetic relatedness, making DZ twins more similar to MZ twins.

Explanation: This question evaluates gene–environment interaction in behavioral genetics using twins, with marketing restrictions moderating snack intake heritability. Restrictions can limit genetic expression, decreasing twin similarity disparities. The vignette shows smaller MZ–DZ differences in restricted households. Choice A is correct, indicating restrictions reduce genetic impact. Choice B overstates, claiming purely environmental origins. Compare concordances across exposures. Interactions reduce genetic variance in limits.

Question 14

Researchers examined epigenetic effects of shift work. Hospital employees worked either rotating night shifts or regular daytime schedules for at least 2 years. Groups were similar in age and job type. Blood samples were analyzed for methylation at regulatory regions near a circadian rhythm gene, and sleep quality was assessed. Night-shift workers showed higher methylation at one regulatory site and poorer sleep quality; DNA sequencing revealed no differences in the gene's coding sequence between groups. The authors suggested that work schedule may influence gene regulation through epigenetic mechanisms.

Which finding is most consistent with the vignette's discussion of epigenetics?

Night-shift work is associated with different methylation patterns near a circadian gene despite unchanged DNA sequence. (correct answer)
Night-shift work causes employees to acquire new circadian alleles through mutation that spreads across the group.
Methylation differences imply that the circadian gene's nucleotide sequence must differ between groups.
Because employees self-select schedules, epigenetic changes cannot be linked to work environment.

Explanation: This question explores gene–environment interaction through epigenetics in behavioral genetics, with shifts altering circadian methylation. Epigenetic modifications regulate genes without sequence changes, affected by schedules. The vignette shows higher methylation and poor sleep in night shifts, no sequence differences. Choice A aligns, highlighting methylation without alteration. Choice C assumes sequence differences from methylation. Focus on regulation. Epigenetics links environment to expression.

Question 15

Investigators studied epigenetic responses to psychotherapy. Adults with elevated anxiety were assigned to either cognitive-behavioral therapy (CBT) or a waitlist for 10 weeks. Before and after, researchers measured methylation near a gene involved in synaptic plasticity and collected anxiety symptom scores. The CBT group showed symptom reduction and decreased methylation at one regulatory region; the waitlist group showed little change. DNA sequencing showed no differences between groups at either time point. The authors proposed that psychological intervention can be linked to changes in gene regulation.

Which finding is most consistent with the vignette's discussion of epigenetics?

CBT is associated with changes in methylation near a plasticity-related gene without changes in DNA sequence. (correct answer)
CBT causes participants to inherit different alleles for synaptic plasticity from their parents.
Symptom reduction requires that the gene's nucleotide sequence mutate during treatment.
Because psychotherapy is psychological, it cannot be associated with any biological changes.

Explanation: This question probes gene–environment interaction via epigenetics in behavioral genetics, with CBT altering plasticity methylation. Epigenetics allows therapy to modify expression without DNA changes. The vignette shows reduced methylation and symptoms in CBT. Choice A aligns, emphasizing changes without sequence shift. Choice C requires mutation for reduction. Ensure focus on regulation. Strategy: epigenetics bridges psychology and biology.

Question 16

A study illustrated gene–environment correlation in academic tracking. Students were genotyped for a polygenic score associated with higher math aptitude. In a district where advanced math placement required a parent request and a teacher recommendation, students with higher scores were more likely to be placed into advanced classes. Parents of high-score students also reported providing more math-related enrichment at home. Advanced placement predicted higher end-of-year math achievement, but the authors cautioned that genetic differences may have influenced access to the advanced environment.

What prediction is most consistent with gene-environment correlation as described?

Only low-score students should benefit from advanced placement if gene–environment correlation is present.
Advanced placement should cause students' polygenic scores to increase by the end of the year.
Polygenic score should be unrelated to parental enrichment because enrichment is purely environmental.
If advanced placement is assigned randomly, the association between polygenic score and class placement should weaken. (correct answer)

Explanation: This question examines gene–environment correlation in behavioral genetics, where polygenic scores affect academic placement. Correlations arise when genes influence access via requests or recommendations. The vignette links scores to advanced classes and enrichment. Choice D predicts weakened association with random assignment, consistent with correlation. Choice B distracts by suggesting scores change. Predict under non-selective conditions. Identify if genes shape opportunities.

Question 17

Researchers used a twin design to examine how access to green space interacts with genetic influences on depression. Monozygotic (MZ) and dizygotic (DZ) twins raised together were assessed at age 20. Some twin pairs lived in areas with high green-space access (within a 10-minute walk to a large park), while others lived in low-access areas. In low-access areas, MZ twins' depression scores were substantially more similar than DZ twins' scores. In high-access areas, both MZ and DZ twins showed lower average depression, and the MZ–DZ difference in similarity was smaller. The authors argued that green space reduced the impact of genetic differences on depression symptoms.

Based on the vignette, which conclusion about genetic predisposition and environment is supported?

Green-space access may reduce the expression of genetic differences related to depression symptoms. (correct answer)
Green-space access eliminates all environmental influences, making depression entirely genetic.
The smaller MZ–DZ difference in high-access areas proves depression is not heritable.
Living near parks causes twins to become genetically identical over time.

Explanation: This question assesses gene–environment interaction in behavioral genetics using twin designs to show how green space moderates depression heritability. Heritability is environmentally contingent, with protective factors like parks reducing the expression of genetic differences in symptoms. The vignette demonstrates this through smaller MZ–DZ similarity gaps in high-access areas, alongside lower depression. Choice A is supported, indicating green space attenuates genetic liability, consistent with moderated expression. Choice C distracts by claiming non-heritability from smaller differences, ignoring that heritability can vary by context. For similar questions, calculate implied heritability changes across environments. Remember, twin studies reveal interactions when concordance patterns shift with environmental exposure.

Question 18

A developmental study examined gene–environment correlation in childhood aggression. Children were genotyped for a variant associated with higher sensation seeking. Researchers observed playground behavior and also recorded peer group characteristics. Children with the sensation-seeking–linked genotype were more likely to affiliate with peers who engaged in rule-breaking games and were more likely to be nominated by classmates as "exciting to play with." The school did not track students into groups; peer affiliation emerged naturally. Later, affiliation with rule-breaking peers predicted more teacher-reported aggression.

What prediction is most consistent with gene-environment correlation as described?

If peer groups are randomly assigned each week, genotype differences in peer affiliation should disappear.
Children with the sensation-seeking–linked genotype should be more likely to place themselves in other high-stimulation settings when available. (correct answer)
Aggressive behavior should cause children's genotype to change toward lower sensation seeking.
Peer rule-breaking norms should predict aggression only among children without the sensation-seeking–linked genotype.

Explanation: This question examines gene–environment correlation in behavioral genetics, where genotypes influence affiliation with stimulating peer environments. Active correlation involves selecting peers or activities that align with genetic traits like sensation seeking, amplifying behavioral outcomes. The vignette shows this with sensation-seeking genotypes linking to rule-breaking peers, predicting aggression. Choice B is correct, forecasting selection into other high-stimulation settings, matching active correlation. Choice C is a distractor, incorrectly positing behavior changes genotypes, reversing causation. To check in future items, predict weakened associations under forced environments. Differentiate correlation types by assessing if genes drive environmental selection.

Question 19

A study tested whether a supportive classroom climate moderates genetic risk for externalizing behavior. Middle-school students were genotyped for a variant in a serotonin transporter gene (alleles S and L) previously associated with impulsivity in stressful contexts. Teachers were trained to implement either a high-support approach (consistent routines, warm feedback) or standard management. Over a semester, disciplinary referrals were tracked. In standard-management classrooms, students with SS had more referrals than SL or LL. In high-support classrooms, referral rates were low and similar across genotypes. The investigators argued that the classroom environment buffered genetic susceptibility.

Which finding is most consistent with the vignette's discussion on gene-environment interaction?

Teacher training affects referrals only by changing parents' genotypes through assortative mating.
Students' genotypes shift from SS to LL after exposure to high-support teaching.
SS genotype predicts more referrals in both classroom types to the same degree.
Students in high-support classrooms show fewer referrals regardless of genotype, with genotype differences minimized. (correct answer)

Explanation: This question tests gene–environment interaction in behavioral genetics, examining how classroom support moderates genetic risk for impulsivity. Interaction occurs when environments like high-support teaching buffer genetic vulnerabilities, reducing phenotypic differences across genotypes. The vignette applies this to the serotonin transporter gene, where high-support classrooms minimize referral disparities for SS genotypes. Choice D aligns by noting low, similar referrals across genotypes in supportive settings, demonstrating buffering. Choice B is a distractor, wrongly suggesting environments change genotypes, which misinterprets interaction as altering DNA. In future questions, look for reduced genetic effects in protective environments as evidence of moderation. A transferable strategy is to identify buffering when outcomes equalize across genotypes in one condition.