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Identical twins Jim Lewis and Jim Springer, adopted by different families as babies, met in 1979 at 39. Both had married a Linda, divorced and married a Betty, named a son James Alan or James Allan, and owned a dog called Toy.

Minnesota Study of Twins Reared Apart, 1979

MindScience

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Their meeting led psychologist Thomas Bouchard at the University of Minnesota to begin the Minnesota Study of Twins Reared Apart, which went on to test well over a hundred pairs of twins brought up in different homes. Because such twins share their genes but not their upbringing, they help show how much of a trait is inherited. The study reported that roughly half the variation in personality, and more of the variation in measured intelligence, was linked to genes. Bouchard himself stressed that the two Jims were unusually alike: most separated twins differ in many ways, and some matches are less remarkable than they sound, since James, Linda and Betty were common names at the time.

Türkçe oku
Tek yumurta ikizleri Jim Lewis ile Jim Springer bebekken ayrı ailelere evlatlık verildi ve ancak 1979'da, 39 yaşında buluştular. İkisi de Linda adında bir kadınla evlenip boşanmış, sonra bir Betty'yle evlenmişti. Oğullarına James Alan ve James Allan adını vermişlerdi, köpeklerinin adı da Toy'du.
Minnesota Ayrı Büyütülmüş İkizler Araştırması, 1979

İkizlerin buluşması, Minnesota Üniversitesi'nden psikolog Thomas Bouchard'ı Minnesota Ayrı Büyütülmüş İkizler Araştırması'nı başlatmaya yöneltti. Araştırmada farklı evlerde büyümüş yüzden fazla ikiz çifti incelendi. Böyle ikizlerin genleri aynı, yetiştirilme koşulları farklı olduğu için bir özelliğin ne kadarının kalıtımla geldiğini anlamaya yardım ederler. Çalışma, kişilik farklarının yaklaşık yarısının, ölçülen zekâdaki farkların ise daha büyük bir kısmının genlerle bağlantılı olduğunu bildirdi. Bouchard, iki Jim'in olağandışı ölçüde benzediğini kendisi de vurguladı: Ayrı büyüyen ikizlerin çoğu birçok bakımdan birbirinden farklıdır. Bazı rastlantılar da göründüğü kadar şaşırtıcı değil, çünkü James, Linda ve Betty o dönemin yaygın adlarıydı.

Sources and further reading

Background reading: Jim Twins
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