General
$100: This is the main topic Kendler et al. (2006) investigated.
Answer: What is the heritability of major depression?
$100: The total number of twin pairs analyzed in the study.
Answer: What is over 42,000?
$100: The heritability estimate for major depression Kendler et al. reported.
Answer: What is approximately 38%?
$100: A term for identical twins.
Answer: What are monozygotic twins?
$100: This is one strength of the study related to sample size.
Answer: What is a large sample size increases generalizability?
$200: The year Kendler et al. conducted their study.
Answer: What is 2006?
$200: The method used to assess depression in participants.
Answer: What are structured interviews?
$200: Kendler et al. found this type of twin had a higher concordance rate for major depression.
Answer: What are monozygotic twins?
$200: A term for non-identical twins.
Answer: What are dizygotic twins?
$200: This type of validity is strengthened by using structured interviews and DSM-IV criteria.
Answer: What is diagnostic validity?
$300: The type of twins used in this study.
Answer: What are monozygotic and dizygotic twins?
$300: The name of the diagnostic tool used for diagnosing depression in this study.
Answer: What is DSM-IV?
$300: Kendler et al. found no significant differences in heritability between these groups.
Answer: What are men and women?
$300: The percentage of genetic material shared by dizygotic twins.
Answer: What is 50%?
$300: A limitation related to the representativeness of twin studies.
Answer: What is low generalizability to the general population?
$400: This country provided the twin sample used in the study.
Answer: What is Sweden?
$400: The type of study design Kendler et al. used.
Answer: What is a correlational twin study?
$400: The study found that environmental factors play a greater role in depression among these twins.
Answer: What are dizygotic twins?
$400: The type of environmental influence shared by twins growing up in the same household.
Answer: What is shared environment?
$400: A critique of the study’s reliance on self-reported data.
Answer: What is potential bias or inaccuracies in self-reports?
$500: The study's participants came from this specific registry.
Answer: What is the Swedish Twin Registry?
$500: These two types of environmental influences were examined in the study.
Answer: What are shared and non-shared environments?
$500: The study concluded this relationship between genetics and environment in causing depression.
Answer: What is gene-environment interaction?
$500: The theory that genes and environment interact to influence behavior.
Answer: What is gene-environment interaction?
$500: This type of bias might occur due to the overestimation of genetic influence in twin studies.
Answer: What is equal environments assumption bias?