[Music]
let’s talk about twins twins turn heads
wherever they go sing two identical
infants children or adults is
irresistible causing us to peer into
baby carriages staring to playgrounds
and even ask rather personal questions
such as who was older who was smarter
and who decides what both of you will do
as if everything twins do is exactly the
same Society tells us that we all differ
in appearance and behavior so when we
encounter two people who look and act so
much alike it challenges our belief and
the way that the world works but we find
ourselves intrigued and drawn into twins
lives trying to understand them for most
of human history psychologists believe
that we were largely products of our
environment but twin research is
teaching us that so many more of our
behaviors than we ever would have
imagined are influenced by the genes
there are two kinds of twins identical
and fraternal and both are essential and
twin research identical twins result
when a single fertilized egg divides
within the first 14 days after
conception and these twins share all
their genes in common fraternal twins
share half the genes on average just
like ordinary brothers and sisters and
they result when a woman releases two
eggs at the same time that is separately
fertilized by two separate sperm we can
compare the similarity of identical
twins in running speed or and how fast
they solve math problems – the
similarity of fraternal twins and if
identical twins are more alike and they
usually are this tells us the genes play
an important role
now most studies use identical twins
raised together but studying the rare
pairs of identical twins reared apart is
even better because if identical twins
raised apart are as alike as identical
twins raised together this is even more
compelling evidence that genes are
important in our development think about
the identical gym twins Jim Lewis and
Jim Springer who grew up in different
Ohio cities they didn’t meet until they
were nearly 40 and they discovered that
both twins bit their fingernails down to
the nub they both drove light blue
Chevrolet’s they both had mixed headache
syndromes beginning in their teenage
years and they both liked to vacation on
the same three-block strip of beach in
Florida the Jim twins also both named
their sons James Allen now James is a
fairly common first name but Allen is a
much less common first or second name
both of the twins had worked part-time
in sheriff’s offices and part-time at
McDonald’s and they loved to scatter
love-letters around the house for their
wives and in a curious twist both twins
had married women named Linda divorced
em and married women named Betty
but then one of the Jim twins divorced
Betty and married sandy we know the
divorce is a partly genetically
influenced trait so you could imagine
the worry and the part of the remaining
Betty now what about the twins Jack and
Oscar they had dramatically different
environments but even that did not
prevent them from amassing a whole list
of similarities that surpassed even
those of the Jim twins Jack was raised
Jewish by his father in Trinidad and
Oscar was raised Catholic by his
grandmother in Nazi Germany and when
they met for the first time they
discovered that both twins like to wear
rubber bands around the wrists they
thought it was funny to sneeze loudly in
elevators they both washed their hands
before and after using the toilet and
they both read books from back to front
and they hated floral centerpieces
because they said it blocked the view of
the person seen it across the table how
do we explain these similarities well it
could be that reading books from back to
front suggests impatience or a sneezing
loudly an elevator is a cry for
attention but regardless the fact that
we see these similarities repeated in
identical twins so much more than
fraternal twins tells us that genes do
play a role Dorothy and Brigitte reared
apart twins in Great Britain they show
us that you don’t have to live with
somebody to be like them you only have
to share their genes when they met for
the first time as adults both twins were
wearing seven rings three bracelets and
a watch and the similarities did not
stop there the twins described
themselves as short-tempered disciplined
and strict they liked the same brand of
perfume they liked the same kinds of
books they had worn nearly identical
dresses to their weddings and carried
nearly identical floral bouquets
they remind me of the identical reared
apart twins mark and Jerry mark and
Jerry grew up in different cities in New
Jersey and they didn’t meet until they
were in their early 30s they were both
volunteer firefighters but their
signature quirk was holding a can of
Budweiser beer with the pinky finger
underneath and you can see that they
also carried huge key rings they attach
to their belts bells had huge buckles on
them they both threw their heads back
sharply when they laughed they were six
foot four bald and heavily moustached
and when I took them out to dinner I
discovered they had a shared passion for
Chinese food and for steak served
extremely rare and I also studied
Barbara and Daphne the giggle twins my
colleagues and I affectionately call
them that because when they met for the
first time they discovered that they
laughed uncontrollably with each other
and with nobody else and they had the
same crooked pinky fingers the same
disinterest in politics and they drunk
they drank their coffee cold black and
without sugar these twins had had a
first miscarriage in their first
pregnancy followed by two healthy boys
and a daughter that may not be so
surprising because female physiology may
in fact the sex of our children and in
this case the physiology was perfectly
matched shortly after they met they
concocted a drink called twin sin that
was made of vodka Blue Curacao creme de
cacao and cream my colleagues and I
thought it was a little curious but the
twins thought it was just delicious I
finally want to mention two sets of
identical twins males born in Columbia
South America one pair from the city one
pair from the country we don’t know how
this half
but early on and the premature nursery
one newborn twin was accidentally
exchanged with one newborn twin in the
other pair so these two sets of brothers
grew up thinking they were fraternal
twins when in fact they were completely
genetically unrelated when they were 25
the truth was discovered and the real
pairs were reunited I went down to
Bogota to study them and I discovered
that the personalities of the reunited
twins aligned almost perfectly in one
case the twins were outgoing gregarious
risk-taking and in the other case they
were introverted little cautious a
little restrained again we don’t fully
understand the reasons behind these
similarities but seeing them repeated in
identical twins more so than fraternal
twins gives us a genetic perspective on
human development now we need to think
seriously about these findings because
they have huge implications for how we
raise our children and how we can all
make the best of our abilities our goals
and our dreams now in my experience
parents of one child are
environmentalists and parents of two
children are geneticists and I say that
because parents of two children realize
rather quickly that what works for one
child doesn’t work for the other and
that’s because children come into the
world with their own genetic
predispositions that lead them towards
certain activities and places and
opportunities parents have to have
realistic expectations about each
child’s – dancing parents may not have a
dancing child because even though each
parent shares half their genes with the
child genes get reshuffled in each
generation you know I tell parents you
don’t really bring up your children they
bring you up because each child evokes
certain treatments and certain responses
from each of their parents a child with
athletic abilities should be given
opportunities to play sports an artistic
child should be given opportune
to paint and to draw and a shy child
should be given opportunity to speak up
more encouraged gently to do so in this
way parents can make a huge difference
in the lives of their children and I
also want to acknowledge the teachers
and the mentors and the managers who
works though closely with twins and
others and affect their lives as a
psychology professor I identified a very
promising undergraduate student one who
showed real ability talent and drive but
he was the first in his family to go to
college and he lacked guidance and
opportunity I work with his students on
a number of projects and today he is an
advanced graduate student at the
prestigious University of Michigan back
to our twins twins are not just mere
objects of fascination just by being
themselves just by acting naturally to
give science a powerful tool for
understanding genetic and environmental
influences on behavior and in this way
they tell us about our humanity why we
are the way that we are and how we got
that way thank you
[Applause]
let’s talk about twins twins turn heads
wherever they go sing two identical
infants children or adults is
irresistible causing us to peer into
baby carriages staring to playgrounds
and even ask rather personal questions
such as who was older who was smarter
and who decides what both of you will do
as if everything twins do is exactly the
same Society tells us that we all differ
in appearance and behavior so when we
encounter two people who look and act so
much alike it challenges our belief and
the way that the world works but we find
ourselves intrigued and drawn into twins
lives trying to understand them for most
of human history psychologists believe
that we were largely products of our
environment but twin research is
teaching us that so many more of our
behaviors than we ever would have
imagined are influenced by the genes
there are two kinds of twins identical
and fraternal and both are essential and
twin research identical twins result
when a single fertilized egg divides
within the first 14 days after
conception and these twins share all
their genes in common fraternal twins
share half the genes on average just
like ordinary brothers and sisters and
they result when a woman releases two
eggs at the same time that is separately
fertilized by two separate sperm we can
compare the similarity of identical
twins in running speed or and how fast
they solve math problems – the
similarity of fraternal twins and if
identical twins are more alike and they
usually are this tells us the genes play
an important role
now most studies use identical twins
raised together but studying the rare
pairs of identical twins reared apart is
even better because if identical twins
raised apart are as alike as identical
twins raised together this is even more
compelling evidence that genes are
important in our development think about
the identical gym twins Jim Lewis and
Jim Springer who grew up in different
Ohio cities they didn’t meet until they
were nearly 40 and they discovered that
both twins bit their fingernails down to
the nub they both drove light blue
Chevrolet’s they both had mixed headache
syndromes beginning in their teenage
years and they both liked to vacation on
the same three-block strip of beach in
Florida the Jim twins also both named
their sons James Allen now James is a
fairly common first name but Allen is a
much less common first or second name
both of the twins had worked part-time
in sheriff’s offices and part-time at
McDonald’s and they loved to scatter
love-letters around the house for their
wives and in a curious twist both twins
had married women named Linda divorced
em and married women named Betty
but then one of the Jim twins divorced
Betty and married sandy we know the
divorce is a partly genetically
influenced trait so you could imagine
the worry and the part of the remaining
Betty now what about the twins Jack and
Oscar they had dramatically different
environments but even that did not
prevent them from amassing a whole list
of similarities that surpassed even
those of the Jim twins Jack was raised
Jewish by his father in Trinidad and
Oscar was raised Catholic by his
grandmother in Nazi Germany and when
they met for the first time they
discovered that both twins like to wear
rubber bands around the wrists they
thought it was funny to sneeze loudly in
elevators they both washed their hands
before and after using the toilet and
they both read books from back to front
and they hated floral centerpieces
because they said it blocked the view of
the person seen it across the table how
do we explain these similarities well it
could be that reading books from back to
front suggests impatience or a sneezing
loudly an elevator is a cry for
attention but regardless the fact that
we see these similarities repeated in
identical twins so much more than
fraternal twins tells us that genes do
play a role Dorothy and Brigitte reared
apart twins in Great Britain they show
us that you don’t have to live with
somebody to be like them you only have
to share their genes when they met for
the first time as adults both twins were
wearing seven rings three bracelets and
a watch and the similarities did not
stop there the twins described
themselves as short-tempered disciplined
and strict they liked the same brand of
perfume they liked the same kinds of
books they had worn nearly identical
dresses to their weddings and carried
nearly identical floral bouquets
they remind me of the identical reared
apart twins mark and Jerry mark and
Jerry grew up in different cities in New
Jersey and they didn’t meet until they
were in their early 30s they were both
volunteer firefighters but their
signature quirk was holding a can of
Budweiser beer with the pinky finger
underneath and you can see that they
also carried huge key rings they attach
to their belts bells had huge buckles on
them they both threw their heads back
sharply when they laughed they were six
foot four bald and heavily moustached
and when I took them out to dinner I
discovered they had a shared passion for
Chinese food and for steak served
extremely rare and I also studied
Barbara and Daphne the giggle twins my
colleagues and I affectionately call
them that because when they met for the
first time they discovered that they
laughed uncontrollably with each other
and with nobody else and they had the
same crooked pinky fingers the same
disinterest in politics and they drunk
they drank their coffee cold black and
without sugar these twins had had a
first miscarriage in their first
pregnancy followed by two healthy boys
and a daughter that may not be so
surprising because female physiology may
in fact the sex of our children and in
this case the physiology was perfectly
matched shortly after they met they
concocted a drink called twin sin that
was made of vodka Blue Curacao creme de
cacao and cream my colleagues and I
thought it was a little curious but the
twins thought it was just delicious I
finally want to mention two sets of
identical twins males born in Columbia
South America one pair from the city one
pair from the country we don’t know how
this half
but early on and the premature nursery
one newborn twin was accidentally
exchanged with one newborn twin in the
other pair so these two sets of brothers
grew up thinking they were fraternal
twins when in fact they were completely
genetically unrelated when they were 25
the truth was discovered and the real
pairs were reunited I went down to
Bogota to study them and I discovered
that the personalities of the reunited
twins aligned almost perfectly in one
case the twins were outgoing gregarious
risk-taking and in the other case they
were introverted little cautious a
little restrained again we don’t fully
understand the reasons behind these
similarities but seeing them repeated in
identical twins more so than fraternal
twins gives us a genetic perspective on
human development now we need to think
seriously about these findings because
they have huge implications for how we
raise our children and how we can all
make the best of our abilities our goals
and our dreams now in my experience
parents of one child are
environmentalists and parents of two
children are geneticists and I say that
because parents of two children realize
rather quickly that what works for one
child doesn’t work for the other and
that’s because children come into the
world with their own genetic
predispositions that lead them towards
certain activities and places and
opportunities parents have to have
realistic expectations about each
child’s – dancing parents may not have a
dancing child because even though each
parent shares half their genes with the
child genes get reshuffled in each
generation you know I tell parents you
don’t really bring up your children they
bring you up because each child evokes
certain treatments and certain responses
from each of their parents a child with
athletic abilities should be given
opportunities to play sports an artistic
child should be given opportune
to paint and to draw and a shy child
should be given opportunity to speak up
more encouraged gently to do so in this
way parents can make a huge difference
in the lives of their children and I
also want to acknowledge the teachers
and the mentors and the managers who
works though closely with twins and
others and affect their lives as a
psychology professor I identified a very
promising undergraduate student one who
showed real ability talent and drive but
he was the first in his family to go to
college and he lacked guidance and
opportunity I work with his students on
a number of projects and today he is an
advanced graduate student at the
prestigious University of Michigan back
to our twins twins are not just mere
objects of fascination just by being
themselves just by acting naturally to
give science a powerful tool for
understanding genetic and environmental
influences on behavior and in this way
they tell us about our humanity why we
are the way that we are and how we got
that way thank you
[Applause]
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