Minnesota Twin Study Overview

Questions and Answers

What was the aim of the Minnesota Twin Study?

To establish the influence of genes or environment on particular traits and characteristics of human beings.

What was the hypothesis of the Minnesota Twin Study?

It was expected that monozygotic twins raised together and apart would have a high concordance rate due to the inheritance of genes. It was also expected that monozygotic twins would have a higher concordance rate than dizygotic twins.

What were the independent and dependent variables of the Minnesota Twin Study?

Independent variables: monozygotic twins reared together (MZT) or apart (MZA), and dizygotic twins reared together or apart (DZT and MZA). Dependent variable: the measurement of IQ using an intelligence test called WAIS.

What was the research design of the Minnesota Twin Study?

Correlational data. Signup and view all the answers

What sampling technique was used in the Minnesota Twin Study?

Use of media coverage to recruit sample - self-selected. Signup and view all the answers

What was the procedure of the Minnesota Twin Study?

Over 100 sets of MZT and DZT twins from around the world were studied, with researchers conducting approximately 50 hours of psychological and physiological testing using the WAIS intelligence test. Signup and view all the answers

What were the results of the Minnesota Twin Study?

Concordance rate for IQ between monozygotic twins reared together was approximately 88%. Similarity rates between monozygotic twins raised apart was at 69%. Bouchard determined a heritability estimate of 70% attributed to genetics and 30% to other factors. Signup and view all the answers

What are the pros of the Minnesota Twin Study?

Much research has supported the findings, making them more reliable; large sample of participants increases external validity. Signup and view all the answers

What are the cons of the Minnesota Twin Study?

Self-selected sample, no control over frequency of contact between twins, equal environment assumption, correlation data cannot establish cause and effect, lack of generalisability due to wealth restrictions. Signup and view all the answers

What are the applications of the Minnesota Twin Study?

The findings can be used to determine the role of genes in intelligence and personality. Signup and view all the answers

What outcomes can the Minnesota Twin Study be used for?

"With reference to relevant research studies, discuss the extent to which genetic inheritance influences human behaviour" and "Outline principles that define the biological level of analysis and explain how these principles may be demonstrated in research." Signup and view all the answers

What are the ethical considerations of the Minnesota Twin Study?

Twins raised apart may have undergone emotional turmoil in being reunited with their twin with whom they've never made contact. Signup and view all the answers

Which experimenter conducted the Minnesota Twin Study?

Bouchard et al. Signup and view all the answers

What year was the Minnesota Twin Study conducted?

<ol start="1990"> <li></li> </ol> Signup and view all the answers

What does Turkeheimer's summary discuss regarding twins and IQ?

A substantial proportion of the twins were raised in impoverished families, showing that IQ variance is affected by environment and socioeconomic status. Signup and view all the answers

Study Notes

Minnesota Twin Study Overview

Aimed to assess the influence of genetic versus environmental factors on human traits and characteristics.
Bouchard et al. conducted the study in 1990.

Study Hypothesis

Anticipated high concordance rates for monozygotic twins whether raised together or apart due to genetic inheritance.
Expected monozygotic twins to show higher concordance in traits than dizygotic twins.

Key Variables

Independent Variables: Monozygotic twins raised together (MZT) vs. apart (MZA) and dizygotic twins (DZT) raised together and apart.
Dependent Variable: IQ measured using the Wechsler Adult Intelligence Scale (WAIS).

Research Design

Utilized a correlational data approach.

Sampling Technique

Relied on media coverage for participant recruitment, resulting in a self-selected sample.

Study Procedure

Involved over 100 sets of twins (MZT and DZT) worldwide.
Conducted approximately 50 hours of psychological and physiological testing, including IQ assessments.

Study Results

Concordance rate for IQ in MZT was around 88%; for monozygotic twins raised apart, it was 69%.
Determined that 70% of intelligence heritability could be attributed to genetics, with 30% from environmental factors.

Advantages of the Study

Supported by substantial research, enhancing reliability of findings.
Large participant sample increases external validity compared to other twin studies.

Limitations of the Study

Self-selected sample due to recruitment methods.
Lack of control over pre-study contact frequency between twins.
Assumed equal environments for twins raised together, leading to assumptions that may not hold true.
Correlational data prevents establishing cause-and-effect relationships.
Limited generalizability as study participants mainly came from affluent backgrounds, with few from poorer socioeconomic statuses.

Applications of Findings

Insights into the genetic basis of intelligence and personality, though difficult to generalize broadly.

Potential Outcomes for Further Discussion

Examination of the impact of genetic inheritance on human behavior in the context of relevant studies.
Identification of biological level principles demonstrated through research findings.

Ethical Considerations

Emotional impact on twins raised apart, especially regarding potential trauma from reuniting after long separations.

Additional Research Reference

Turkeheimer's study analyzed IQ scores in 7-year-old twins, indicating that environmental factors significantly influence intelligence, particularly in impoverished families, contrasting with affluent environments where genetic factors are more influential.

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Description

Explore the Minnesota Twin Study conducted by Bouchard et al. in 1990, which investigates the impact of genetic versus environmental influences on human traits. The study examines the differences in IQ concordance rates between monozygotic and dizygotic twins, shedding light on the nature versus nurture debate.