Transcript Identical Twin Studies

Peter Neubauer did a series of
experiments on identical twins given up
for adoption in the late 1960s
 He separated the twins at adoption and
put them in different homes, leaving the
infants to be studied by teams of
physicians, psychologists,
psychoanalysts, and more.
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Beth went to a good home with loving
parents with a good income. Her mother
went out of her way to make Beth feel
loved and welcomed in the family. They
were not very strict and made sure Beth
knew that she would be loved in her
family no matter how she did in school
 Upper class
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Amy was sent to a home where her
mother was jealous of the way she
looked. Her brother was considered the
“golden boy” and basically put on a
pedestal. Amy’s father saw what was
going on but ignored it, eventually
joining in on the behaviors.
 Lower class

They were both sent to Jewish homes in
New York
 Their mothers stayed home
 They each had a brother 7 years older
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Traits:
› Thumb-sucking, nail-biting, bed-wetting
› Learning disorder
› Gender confusion, role-playing, artificial quality
› Longing for maternal attention
› Hypochondriac and pathologically immature
› “the picture of a neglected child”
Which twin do you think this is?
13 children were involved in the study, 5
sets of identical twins and one set of
identical triplets, all separated at
adoption
 Due to controversy, his results are sealed
until the year 2066 and currently reside in
the archives at Yale University

Not birth.
 Twins share common experiences in the
womb, they hear the same sounds, get
the same nutrition, and can become
addicted to the same substances
 Even if you separate twins at birth, they
may have similarities based on their time
in the womb

When a mother separates twins, if she
does, she will often give one of the
children to a close relative, or someone
who shares the same views and
parenting styles as herself
 Adoption agencies, too, will often give
siblings to similar households; it is not
random selection, but a very intense
interview process

Because they look the same, people
treat them the same
 Parents will dress identical twins in
identical clothing, people will confuse
the two, their teachers will speak to
them the same way, etc
 Twins subconsciously mimic each other
because they see someone who looks
like them, and because people expect
them to act alike

Identical twins are the same height, have
the same hair and eye color, and have
similar musculature (among other things),
which means they will see the world from
the same place (eye level), they may
attract the same kind of spouse, and they
may be good at the same types of sports.
 Experiences based on their DNA (such as
getting glasses at the same age) may
influence them to be a certain way.

Mitochondrial DNA comes from the
mother, after conception, in most cases
with twins, after the “split”
 This means that identical twins can have
different mitochondrial DNA

Twins with a biological parent who is an
alcoholic were separated. One was
raised with the alcoholic parent, and
one was raised in an alcohol-free home.
 Both twins grew up to become
alcoholics

Adopted away children of alcoholics are
four times more likely to become
alcoholics themselves than children of
non-alcoholics
 Genetics have been shown to play a
role in alcohol addiction in men.
 Genetics have do not seem to play as
much of a role in women

Neil Whitehead did a study on
homosexual twins. He found sets of
identical twins and asked about their
sexual orientation, among other things.
 When one twins was homosexual, the
other was less than 50% of the time. If
homosexuality was caused by genetics,
then the percentage would have been
100%
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Beetle. (2004, October). Identical Twin Studies and Evolutionary Psychology.
Retrieved February 4,
2013, from Homestead website:
http://drbeetle.homestead.com/twins.html
Richman, J. (2007, October 25). 'Identical Strangers' Explore Nature Vs. Nurture.
Retrieved February
4, 2013, from NPR website:
http://www.npr.org/2007/10/25/15629096/identical-strangersexplore-naturevs-nurture
Sparknotes Editors (Ed.). (n.d.). Sparknote on Addiction. Retrieved February 6,
2013, from
Sparknotes website:
http://webpath.follettsoftware.com/resource/viewurl?encodedUrl=QA3e1Z
mfGQTyUhHafx
GQj39a9aC8L1a9mU63Acf1vQ&version=1&appsignature=Destiny&appversion=10.5.6.0+%28RC6%29
Whitehead, N. (n.d.). The Importance of Twin Studies. Retrieved February 9, 2013,
from
http://www.narth.com/docs/whitehead2.html
Winerman, L. (2004, April). A second look at twin studies. Retrieved February 4,
2013, from
American Psychology Association website:
http://www.apa.org/monitor/apr04/second.aspx
Wright, L. (1997). Twins. Retrieved February 4, 2013, from New York Times website:
http://www.nytimes.com/books/first/w/wright-twins.html