Biological Psychology Flashcards

Flashcards for reviewing key concepts from the Biological Psychology lesson on twin studies and Brendgen et al. (2005).

What is the main purpose of twin studies in research?

To understand genetic and environmental influences on traits.

How do twin studies relate to the 'nature' explanation of human behavior?

They help determine the extent to which innate biological factors influence traits.

How do psychologists use twin studies to investigate clinical disorders?

They determine the probability that twin pairs might inherit disorders like schizophrenia.

What percentage of DNA do identical twins share?

100%

What percentage of DNA do fraternal twins share?

50%

What is the purpose of comparing concordance rates between twin pairs?

To determine the likelihood of both or one twin inheriting a particular trait.

Define Zygosity

The degree of similarity between the alleles for a trait in an organism.

Define Monozygotic Twins (MZ)

Identical twins developed from one zygote, which splits and forms two embryos. Share 100% DNA

Define Dizygotic Twins (DZ)

Fraternal twins, each twin developed from a separate egg fertilised by individual sperm cells. Share 50% DNA

Define Concordance

A positive or negative correlation between the IV/DV.

Define Genotype

The complete genetic heritability (e.g. the alleles inherited Bb).

Define Physical aggression

Hitting, punching, physical violence displayed by children.

What are the two types of Social Aggression?

Relational aggression and Indirect aggression

What was the aim of Brendgen's (2005) twin study?

To investigate the extent to which social aggression could be explained by genetic, shared environmental, or nonshared environmental factors, and to what extent the covariance between physical and social aggression could be explained by these factors.

What were the Independent and Dependent Variables in Brendgen's (2005) study?

IV: Type of twin pair (MZ or DZ). DV: Teacher and peer ratings for social and physical aggression.

Who were the participants in Brendgen's (2005) study?

234 pairs of MZ/DZ twins taken from the Quebec Newborn Twin Study, Canada, aged 6 years old.

What type of sampling method was used in Brendgen's (2005) study?

Opportunity/Cluster Sample.

What was the procedure for data collection in Brendgen's (2005) study?

Teacher ratings based on agreement with statements and peer ratings involving classmates identifying classmates fitting behavior descriptions.

What statistical test was used in the Brendgen study?

Chi Squared inferential test

According to Brendgen's 2005 study, Approximately what percentage of social aggression is explained by the ACE model?

genetic and shared environmental factors each accounted for 20% of social aggression.

According to Brendgen's 2005 study, what percentage of physical aggression accounted for?

genetic heritability accounted for 54% of the physical aggression.

What were the main conclusions of Brendgen's (2005) study?

Physical aggression is mostly nature (genes), while social aggression is mostly nurture (environment). Genes might give a predisposition towards aggression, but the environment determines if it becomes social aggression.

What does GRAVE stand for when evaluating studies?

Generalisability, Reliability, Application, Validity, Ethics

What are the two types of reliability?

Inter-rater and test-retest

Explain how Brendgen's study might have low generalizability.

Twins are a unique population, and sampled only from Quebec, limiting generalizability to other populations and cultures.

What is a strength of Brendgen's study in terms of reliability?

The use of questionnaires allows for easy replication, making the study repeatable. Two researchers also visited the classroom to administer the study allowing for inter-rater reliability.

How might Brendgen's study be considered unethical?

It involves children judging their classmates, which could negatively impact friendships and cause psychological harm.

How can Brendgen's study be applied?

The results have implications for preventive interventions in schools, suggesting that reducing physical aggression early on might prevent social aggression.

Name one weakness of twin studies.

Correlation does not mean causation because of the quasi-experimental design