Thomas J. Bouchard
Thomas Bouchard was a man who specifically studied identical twins separated at birth which has been the most famous research on genetic influences in humans. However, the purpose of studying identical twins who were separated at birth and raised by different families, was that Thomas Bouchard could analyse similarities and/or differences which might have emerged despite a different family environment and upbringing.
One specific example was The Minnesota Twin Study. Thomas Bouchard directed this study which began in 1979 and involved several assessments including medical and psychological factors of fraternal twins separated not long after being born and reared apart. The psychological assessment involved rigorous testing which included multiple measures of personality traits, personal values, intellectual abilities, interests, psychomotor skills, reading, writing and spelling. The medical assessment encompassed areas such as a psychiatric interview, a medical life history, a standard blood battery and even intricate dental exams. The evidence that identical twins show many remarkable similarities can all stem from this single massive study.
Twins Gerald and Mark Newman were separated as infants and grew up to share characteristics ranging from their jobs as fire-fighters to even taste in beer. However, as they were separated as young babies, neither knew of the other’s existence until an acquaintance brought them together. Upon meeting for the first time, many similarities emerged. Each man saw his own reflection- while both had grown the same moustache and wore the same glasses, they had discovered they had more than looks in common. These similarities ranged from studying the same subject at college (forestry) and graduating with degrees for trimming city trees. Both men also worked in supermarkets for a period of time and Gerald previously had a job installing sprinkler systems while Mark had a job installing fire alarms. In addition, both twins share pastimes of hunting, fishing, going to the beach and eating food. Though both were raised in the Jewish faith, neither formally practised the religion.
Following on from the Minnesota study, the twins completed a series of interviews and tests, as with any other case-study. The results from these tests reported back that heredity accounted for 64 to 74 per cent of the differences observed in IQ between the twins. This finding is a 16 to 17 per cent increase of the variance where previous studies found that heredity proved 47 to 58 per cent of the difference.
Therefore from these findings, we can conclude that the majority of twins seem to share similar personalities- peculiarities of manner and personal preferences such as habits, hobbies and interests, likings, tastes in clothes, food, occupations and choices of names.
Additionally, the authors and investigators of many twin/identical twins studies have claimed that the environments which the twins reside in do little to create differences in intelligence, personality and intellectual abilities.
And for this, genes are responsible for the similarities which occur between twins, not the environment or upbringing because the differences between twins brought up apart must be solely due to the environment.
However, if genes were the primary reason why identical twins possessed multiple similarities, it would directly contradict what was previously said regarding the fact that a particular person’s emotional characteristic’s was dependant on the environment of upbringing throughout their life, to a certain extent.
One specific example was The Minnesota Twin Study. Thomas Bouchard directed this study which began in 1979 and involved several assessments including medical and psychological factors of fraternal twins separated not long after being born and reared apart. The psychological assessment involved rigorous testing which included multiple measures of personality traits, personal values, intellectual abilities, interests, psychomotor skills, reading, writing and spelling. The medical assessment encompassed areas such as a psychiatric interview, a medical life history, a standard blood battery and even intricate dental exams. The evidence that identical twins show many remarkable similarities can all stem from this single massive study.
Twins Gerald and Mark Newman were separated as infants and grew up to share characteristics ranging from their jobs as fire-fighters to even taste in beer. However, as they were separated as young babies, neither knew of the other’s existence until an acquaintance brought them together. Upon meeting for the first time, many similarities emerged. Each man saw his own reflection- while both had grown the same moustache and wore the same glasses, they had discovered they had more than looks in common. These similarities ranged from studying the same subject at college (forestry) and graduating with degrees for trimming city trees. Both men also worked in supermarkets for a period of time and Gerald previously had a job installing sprinkler systems while Mark had a job installing fire alarms. In addition, both twins share pastimes of hunting, fishing, going to the beach and eating food. Though both were raised in the Jewish faith, neither formally practised the religion.
Following on from the Minnesota study, the twins completed a series of interviews and tests, as with any other case-study. The results from these tests reported back that heredity accounted for 64 to 74 per cent of the differences observed in IQ between the twins. This finding is a 16 to 17 per cent increase of the variance where previous studies found that heredity proved 47 to 58 per cent of the difference.
Therefore from these findings, we can conclude that the majority of twins seem to share similar personalities- peculiarities of manner and personal preferences such as habits, hobbies and interests, likings, tastes in clothes, food, occupations and choices of names.
Additionally, the authors and investigators of many twin/identical twins studies have claimed that the environments which the twins reside in do little to create differences in intelligence, personality and intellectual abilities.
And for this, genes are responsible for the similarities which occur between twins, not the environment or upbringing because the differences between twins brought up apart must be solely due to the environment.
However, if genes were the primary reason why identical twins possessed multiple similarities, it would directly contradict what was previously said regarding the fact that a particular person’s emotional characteristic’s was dependant on the environment of upbringing throughout their life, to a certain extent.