Minnesota Twin Study

AIM OF STUDYIt seeks to identify the genetic & environmental influences on the development of psychological traits.

METHOD & COLLECTING DATALongitudinal study of 11-17 year-old twins, started in 1979. Involved a week-long of medical & psychological assessment or identical and fraternal twins separated in early life. Medical Assessment: - Psychiatric interview - Medical life history - Standard blood test - Detailed dental & periodontal exams

METHOD &COLLECTING DATAPsychological Assessment: -Academic ability -Personality & Interests -Family & Social relationships -Mental & Physical health -Psychological MeasurementsA systematic assessment of aspects of the twin's rearing environments that might have had causal roles in their psychological development is also carried out. This study provided many examples of separated identical twins showing multiple similarities.

FINDINGS (EXAMPLES)Twins reared apart: Thomas Bouchard found that an identical twin reared away from their co-twin seemed to have about an equal chance of being similar to their twin in personality, interests & attitudes as on who has been reared with his/her co-twin.

FINDINGS (examples)Separated as infants, twins Gerald (Jerry Levey) and Mark Newman grew up to share characteristics ranging from their firefighting avocation to taste in beer.Neither of them knew of the others existenceWhen they first met, they saw their reflection in the other person.Grew same mustache, wore the same glasses.Both worked in supermarkets for a while.Both men are bachelors and are attracted to the same kind of woman.Both volunteer fire fighters.Both brought up in the Jewish faith but neither is particularly religiousBoth men drink only Budweiser Beer. ( They even hold the can in the same way)DIFFERENCES: IQ LEVEL AND THINKING SKILLS

Influence of Nature & NurtureNature:Sharing same genes, gives us physical traits and behavior characteristics

Nurture:Lifestyle, EnvironmentShowed in their working habits and thoughtsNurture cultivates the nature

CONCLUSION This leads to the conclusions that most similarities between twins are due to genes rather than from the environment they live in. This is because the DIFFERENCES of twins which had been reared apart must have been due to their environment.

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