Twins: Research into Nature and Nurture


[ MUSIC ]>>HELLO AND WELCOME
TO TALKING POINTS. I’M DAVE KELLY, DIRECTOR OF
ADVANCED MEDIA PRODUCTION AT CAL STATE LONG BEACH. TODAY WE’RE GOING TO
EXPLORE THE MYSTERY OF TWINS AND WHAT THE RESEARCH IS
TELLING US ABOUT TWINS IS IN THEIR RELATIONSHIPS. MY GUEST TODAY IS
DOCTOR NANCY SEGAL. DOCTOR SEGAL IS AN AWARD
WINNING PROFESSOR OF PHYCOLOGY AT CAL STATE FULLERTON AND SHE
IS ALSO THE FOUNDER AND DIRECTOR OF THE TWIN STUDY CENTER. WELCOME NANCY AND THANK
YOU FOR TAKING TIME AWAY FROM YOUR VERY BUSY
SCHEDULE TO SPEND TIME WITH US IN THE STUDIO.>>IT’S MY PLEASURE DAVE.>>WELL YOU ARE A WORLD
RENOWNED RESEARCHER IN THIS AREA AND AUTHOR AS WELL THAT
PERHAPS NOW WE SHOULD START THE CONVERSATION BY REVEALING
TO OUR AUDIENCE WHY IT IS THAT YOU BECAME SO
INTERESTED IN THIS AREA OF ACADEMIC RESEARCH
THAT IS TWIN STUDIES.>>DAVE THEY’RE ACTUALLY TWO
REASONS WHY I’M IN THIS FIELD AND THE FIRST IS THAT
I AM A TWIN MYSELF. I HAVE A PATERNAL TWIN
SISTER, ANN, WHO LOOKS AND BEHAVES NOTHING LIKE ME
AND I WAS ALWAYS SO FASCINATED WITH THAT AS A CHILD WONDERING
HOW TWO CHILDREN COULD END UP IN THE SAME FAMILY WITH
THE SAME EXPERIENCES AND YET BE SO VERY DIFFERENT. THEN I WENT TO COLLEGE AT
BOSTON UNIVERSITY AND MAJORED IN PHYCOLOGY AND TOOK
A WONDERFUL CLASS IN PERSONAL ADJUSTMENT
AND IN THE COURSE OF WRITING AN ASSIGNMENT
FOR THAT CLASS, I CAME UPON TWIN STUDIES. AND I WAS JUST HOOKED; I
THOUGHT THEY WERE FASCINATING. I COULD RELATE TO THEM BOTH
PERSONALLY AND PROFESSIONALLY AND SO MY CAREER
ESSENTIALLY SEALED WHEN I WAS A SENIOR IN COLLEGE.>>AND YOU ARE A FRATERNAL
TWIN AS YOU’VE JUST MENTIONED SO WE SHOULD PROBABLY
IDENTIFY WHAT THOSE TERMS MEAN. FRATERNAL TWIN MEANS THAT YOU
HAVE WHAT’S CALLED THE DIZYGOTIC SITUATION WHEN THE MOTHER
IS READY TO HAVE TWINS; THERE’S ACTUALLY TWO SEPARATE
EMBRYOS THAT WERE FERTILIZED SO THEIR INDEPENDENT
OF EACH OTHER. THAT’S DIFFERENT FROM
THE IDENTICAL TWINS, WHICH ARE CALLED MONOZYGOTIC,
WHICH IS ONE EGG INITIALLY. IT’S ONE ZYGOTE, WHICH IS
THE PRECURSOR TO THE EMBRYO THAT SPLITS INTO TWO EMBRYOS
AND THEN YOU HAVE TWO SETS OF CHILDREN; TWO EMBRYO’S THERE; THAT THE EXACT SAME
GENETIC MATERIAL. SO IDENTICAL TWINS ARE
DIFFERENT FROM FRATERNAL TWINS.>>WELL I CAN SEE THAT
YOU’VE DONE YOUR HOMEWORK. YOU’VE GOT IT EXACTLY RIGHT. AND THE BEAUTY OF THE
TWO TYPES OF TWINS IS THAT WE COMPARE THE
SIMILARITIES IN IDENTICAL PAIRS TO THE SIMILARITIES
IN FRATERNAL PAIRS. IF THE IDENTICALS ARE MORE ALIKE
WITH RESPECT TO INTELLIGENCE, PERSONALITY, JOB SATISFACTION
OR SELF-ESTEEM, THIS TELLS US THAT THOSE TRAITS HAVE A
PARTIAL GENETIC EFFECT. AND WE FIND THAT VIRTUALLY ALL
MEASURED TRAITS THERE’S SOME GENETIC COMPONENT. IT’S A BEAUTIFUL,
NATURAL DESIGN.>>AND YOU SO TALKED ABOUT
IN THE FIRST QUESTION OR THE FIRST ANSWER ABOUT THE
FACT THAT THERE WERE DIFFERENCES BETWEEN YOU AND YOUR SISTER IN
TERMS OF PERSONALITY AND TRAITS AND SO ON, BUT WITH
IDENTICAL TWINS WE FIND THAT THEY TEND TO
BE MORE SIMILAR. WHY IS THAT?>>IDENTICAL TWINS ARE MUCH
MORE ALIKE THAN FRATERNAL TWINS ON VIRTUALLY EVERY
MEASURED TRAIT. AND THE REASON FOR THAT IS
THAT THEY SHARE THEIR GENES. THEY ARE ONE HUNDRED PERCENT
GENETICALLY THE SAME AND SO IN COMBINATION WITH
THE ENVIRONMENTS IN WHICH THEY’RE RAISED, THEY’RE
BEHAVIORS, THEIR INTELLIGENCE, THEIR PERSONALITIES ARE
FAIRLY WELL MATCHED. IT’S NOT PERFECT SIMILARITY; IN
FACT WE DON’T FIND CORRELATIONS OF ONE FOR ANYTHING THAT
WE MEASURE IN IDENTICALS, BUT THE IMPORTANT POINT IN
THEY ARE MUCH MORE ALIKE THAN ANY OTHER PAIR OF PEOPLE. AND WE NEED THAT
COMPARISON OF THE FRATERNALS. I THINK THAT MANY PEOPLE ARE SO
STRUCK BY THE VISUAL INTEREST OF IDENTICAL TWINS, BUT FRATERNALS ARE THESE
ESSENTIAL COMPARISON GROUPS IN ANY TWIN RESEARCH PROJECT.>>AND IF WE TALK
ABOUT THE IDENTICALS, THEY DO HAVE SOME
MINOR DIFFERENCES; FOR EXAMPLE THEY DON’T HAVE
THE SAME FINGER PRINTS. AND IN SOME CASES ONE MIGHT HAVE
SCHIZOPHRENIA AND THE OTHER NOT.>>THAT’S A MAJOR DIFFERENCE.>>WELL OK, WELL THAT
WOULDN’T BE A MINOR DIFFERENCE, AS YOU SAY THAT WOULD BE MAJOR. ARE THERE ENVIRONMENTAL
INFLUENCES OR WHAT WE WOULD REFER TO
IS MEDIAGENIC INFLUENCES THAT AFFECT THESE
DIFFERENCES AMONG IDENTICALS?>>WELL IT’S IMPORTANT
TO FIND OUT AS YOU SAY THAT IDENTICAL TWINS
ARE NOT EXACTLY THE SAME AND THIS CAN HAPPEN FOR
A VARIETY OF REASONS. IT COULD BE SOME
PRENATAL EFFECT; PERHAPS ONE TWIN RECEIVED
MORE PRENATAL NUTRITION THAN THE OTHER TWIN. IN FACT THE BIRTH WEIGHTS OF
IDENTICAL TWINS ARE LESS ALIKE THAN THE BIRTH WEIGHTS OF
FRATERNAL TWINS; ALTHOUGH, OVER TIME THEY EVENTUALLY
BECOME MORE CONCORDANT. BUT EPIGENETICS, THE TURNING
ON AND TURNING OFF OF GENES, THAT DOES NOT CHANGE THE DNA, BUT WHAT IT DOES CHANGE
IS THE EXPRESSION THOSE PARTICULAR TRAITS. THAT’S ALSO A POSSIBILITY. IT COULD BE POST-NATAL EXPOSURE
TO CERTAIN THINGS, INFECTION, OR SOME TRAUMATIC EVENT
COULD CAUSE A DIFFERENCE BETWEEN IDENTICAL TWINS AND
THIS IS WHAT’S SO FASCINATING BECAUSE WHEN WE SEE DIFFERENCES
BETWEEN IDENTICAL TWINS, IT CAN TELL US WHAT IS THE
EFFECT THAT MIGHT CAUSE OR PREVENT A CONDITION IN
THE NON-TWIN POPULATION. SO TWINS THAT IS, NOT JUST
FOR TWINS, THERE ARE MODEL; THEY’RE LOOKING AT BEHAVIOR AND MEDICAL CONDITIONS
FOR EVERYBODY ELSE.>>AND A DESCRIPTION OF YOU
THAT WAS WRITTEN RECENTLY SAID THAT AS A PROFESSOR OF
DEVELOPMENTAL PHYCOLOGY, DOCTOR SEGAL’S INTEREST LIE
IN THE JUNCTURE OF GENETICS, EVOLUTIONAL PHYCOLOGY
AND TWIN STUDIES. WHAT DOES THAT ALL MEAN?>>WELL IT ALL MEANS THAT RESEARCH IS NOW VERY
HIGHLY INTERDISCIPLINARY AND SO BEHAVIOR GENETICS
IS A STUDY OF THE GENETIC TRANSMISSION OF
BEHAVIOR ACROSS GENERATIONS. AND NO BETTER STUDY THAT
IS TO USE TWIN STUDIES. AND I’M VERY INTERESTED IN
DEVELOPMENT AND SO IF YOU LOOK AT TWIN STUDIES OVER TIME,
THAT WILL GIVE YOU CLUES AS TO DIFFERENT TRAITS AND
HOW THAT MIGHT CHANGE AND WHY. AND IF YOU TAKE A LOOK AT
EVOLUTIONARY PHYCOLOGY, THE IDEA OF TRYING TO FIND OUT WHY CERTAIN BEHAVIORS
ARE ADAPTIVE IN OUR CURRENT ENVIRONMENT; WHY THEY REMAINED THROUGHOUT
THE COURSE OF HUMAN HISTORY, TWIN STUDIES ARE
ALSO A WAY OF LOOKING AT A SPECIFIC HYPOTHESIS RELATED
TO EVOLUTIONARY PHYCOLOGY, PARTICULARLY WHEN IT COMES TO
COOPERATION BETWEEN INDIVIDUALS.>>WELL LET’S TALK ABOUT
THE FREQUENCY OF TWINS BECAUSE THEY ARE ACTUALLY
FRATERNAL, AT LEAST, BECOMING MORE FREQUENT TODAY; WE’LL GET TO THAT
IN JUST A MOMENT. BUT AS FAR AS FRATERNAL
VERSUS IDENTICAL, YOU’RE MUCH MORE
LIKELY TO HAVE FRATERNAL BECAUSE THEY ARE
TWO SEPARATE EGGS THAT ARE FERTILIZED WHEREAS
THE OTHER ONE INVOLVES THAT SPLITTING OF ONE ZYGOTE,
WHICH IS MUCH MORE RARE. SO STATISTICALLY
SPEAKING ABOUT ONE OUT OF EVERY THREE HUNDRED
THIRTY THREE BIRTHS OR THREE OUT OF A THOUSAND
WOULD BE IDENTICAL; WHEREAS WITH THE FRATERNAL
TWINS IT’S MORE LIKE THREE OUT OF A HUNDRED OR
ABOUT THREE PERCENT. THAT NUMBER HAS ACTUALLY STARTED
TO GO UP PRETTY DRAMATICALLY SINCE ABOUT NINETEEN EIGHTY. IN FACT I THINK IT’S UP AT LEAST
SEVENTY SIX PERCENT SINCE THEN. WHY IS THAT?>>WELL LET’S FIRST TALK
ABOUT NATURAL TWINNING RATES AND THE TWINNING RATES
WE’RE SEEING NOW. THE NATURAL TWINNING RATE IS
ABOUT ONE IS EIGHTY BIRTHS. SINCE NINETEEN EIGHTY, THE
TWINNING RATE HAS ACTUALLY GONE UP TO IN ONE IN THIRTY
BIRTHS IN WESTERN COUNTRIES AND THERE ARE TWO
REASONS FOR THAT. THE FIRST REASON IS THAT WOMAN
DELAYING THE CHILD BEARING YEARS TO ESTABLISH THEMSELVES
PROFESSIONAL TO COMPLETE EDUCATIONAL
PROGRAMS. AND SO WHEN YOU DELAY
THE CHILD BEARING YEARS, WHAT YOU’RE DOING IS
INCREASING THE PROBABILITY OF RELEASING TWO EGGS. NOW YOU CAN THINK OF THAT
AS A REPRODUCTIVE MISTAKE BECAUSE WOMEN ARE BEST GEARED
TO HAVING ONE BABY AT A TIME. ON THE OTHER HAND, IT’S
KIND OF A NICE MISTAKE TO HAVE TWO CHILDREN AT
ONE TIME, INSTANT FAMILY, AND ONE HOSPITAL BILL. NOW THE OTHER REASON
THAT TWINNING IS GOING UP AND THIS COUNTS FOR
ABOUT TWO THIRDS OF THE RISE ARE FERTILITY
TREATMENTS, FERTILITY DRUGS, IN VITRO FERTILIZATION, OTHER
REPRODUCTIVE TECHNOLOGIES THAT ASSIST IN VIRAL
WOMEN IN HAVING FAMILIES. BUT ONE THING THAT’S
IMPORTANT TO POINT OUT, IT IS NOT JUST FRATERNAL
TWINNING THAT’S GOING UP, BUT IT’S ALSO IDENTICAL
TWINNING; ALL BE IT NOT THE SAME RATE. WHEN YOU MICRO MANIPULATE
AN EGG IN THE LABORATORY FOR IN VITRO FERTILIZATION
PURPOSES, THIS ALSO CREATES AS A PROBABILITY OF
SPLITTING THAT FERTILIZED EGG AND SO MANY COUPLES WONDER
GO FOR FERTILITY TREATMENT AND PRODUCE TWINS WHO ARE
IDENTICAL ARE SORT OF SHOCKED BECAUSE THEY WERE
EXPECTING FRATERNALS. BUT IDENTICAL TWINNING
RATE HAS GONE UP AND ONE MORE REASON IT
HAS CONTRIBUTED TO THIS IS THAT WE ARE MUCH BETTER
ABLE TO DETECT PREGNANCIES AND MANAGE THEM THROUGHOUT
THE PREGNANCY.>>SO SCIENTIFIC
MANIPULATION, IF YOU WILL, HAS HAD A PRETTY IMPORTANT
IMPACT ON ALL OF THIS.>>YES IT HAS.>>OK, SO LET’S TALK ABOUT DIET
BECAUSE THERE ARE SOME STUDIES THAT SHOW THAT DIET ALSO
PLAYS A ROLE IN TWINNING.>>THAT’S RIGHT.>>AND WHAT ABOUT THE
DIET AND WHAT ABOUT VEGANS WHO ARE NOT ABLE TO HAVE
TWINS NEARLY AS EASILY AS PEOPLE THAT ARE VEGANS?>>WELL THEY KNOW THAT PROTEIN
IS A VERY IMPORTANT CONSTITUENT IN THE DIET IF ONE IS
GOING TO HAVE TWINS. AND VEGANS TEND TO HAVE A LOWER
RATE OF TWINNING THAN PEOPLE WHO ARE MEAT EATERS THAT GET
A LOT OF THE NATURAL PROTEIN. THEY ALSO KNOW THAT IN
YORUBA IN WESTERN NIGERIA, IT SEEMS THAT A VERY
PARTICULAR KIND OF SWEET POTATO, THE WHITE YAM, SEEMS TO
BE LINKED TO THE HIGH RATE OF TWINNING AMONG THE
YORUBA FROM WESTERN NIGERIA. AND IT’S NOT JUST THE WHITE YAM, BUT IT MAY BE ALSO
SOMETHING ABOUT THOSE WOMEN. FOR SEVERAL REASONS THEY HAVE
A GENETIC LIKE PROPENSITY TO RELEASE TWO OR THREE
EGGS AT THE SAME TIME. KEEP IN MIND TOO, THAT
THE YORUBA WOMEN HAVE BEEN ON THIS DIET FOR
ALL OF THEIR LIVES; SO IT MIGHT WELL BE ACCUMULATIVE
EFFECT WHEREAS I THINK THAT WOMEN TODAY HERE IN
THE U.S., IF THEY WANTED TO HAVE TWINS SHOULD NOT JUST
START EATING WHITE YAMS ALL OF A SUDDEN BECAUSE THEY
MIGHT BE DISAPPOINTED.>>APPARENTLY THERE IS SOME
SORT OF NATURAL FIDO ESTROGEN IN THAT WHITE YAM THAT AS YOU
SAY; IT’S NOT NECESSARILY GOING TO YIELD TWINS IF YOU START
EATING IT TODAY HOPING FOR THE BEST.>>THAT’S RIGHT; FRATERNAL
TWINNING IS A VERY COMPLEX PROCESS AND THERE ARE
MANY FACTORS LINKED TO IT. ONE IS GENETIC PREDISPOSITION
IN THE FAMILY. IF YOU’RE OF AFRICAN DESCENT, YOU HAVE A HIGHER
RATE OF TWINNING. IF YOU ARE TALL OR HEAVY OR MOTHER SEES [INAUDIBLE]
HAS BEEN IMPLICATED; FREQUENCY OF INTERCOURSE; MANY, MANY THINGS EFFECT
FRATERNAL TWINNING. BUT HERE’S THE INTERESTING
THING DAVE THAT AS MUCH AS WE STUDY IDENTICAL TWINNING,
NOBODY REALLY KNOWS WHY THAT FERTILIZED EGG DIVIDES. AND I THINK THAT’S FASCINATING.>>OK WELL LET’S TALK ABOUT
A STUDY THAT WAS CONDUCTED AND THE RESULTS WERE RELEASED
IN MAY OF TWENTY FIFTEEN AND THIS WAS A REPORT
THAT ISSUED IN A JOURNAL CALLED
NATURE GENETICS. THERE WERE RESEARCHERS;
I THINK YOU KNOW WHO THOSE RESEARCHERS ARE. ONE WAS FROM AMSTERDAM I BELIEVE AND THE OTHER WAS
FROM AUSTRALIA. THEY STUDIES FIFTY YEARS’
WORTH OF RESEARCH ON TWINS AND IT COVERED SOMETHING
LIKE FOURTEEN AND A HALF MILLION
TWINS AND THE QUESTION, THE CENTRAL QUESTION WAS, IT IS
NATURE, IN OTHER WORDS GENETICS, OR IT IS NURTURE
OR THE ENVIRONMENT THAT HAS THE MOST EFFECT UPON
US TO MAKE US WHO WE ARE. AND THERE ALWAYS
HAVE BEEN DEBATES ABOUT THAT NATURE
VERSUS NURTURE. WELL THE REPORT CAME OUT THAT
IT ACTUALLY WORKED OUT TO ABOUT FORTY NINE PERCENT, FIFTY ONE PERCENT
ENVIRONMENTAL OR NURTURE. WHAT ABOUT THAT? IS THAT IN ANY WAY SURPRISING
AND WHAT DOES IT TELL US?>>IT’S NOT SURPRISING
TO ME AT ALL AND IN FACT WE REALLY
DON’T SPEAK ABOUT NATURE OR NURTURE ANYMORE. IT’S REALLY NATURE AND NURTURE BECAUSE THEY BOTH
AFFECT EVERYTHING ABOUT HUMAN BEHAVIOR
AND DEVELOPMENT. BUT THAT’S REALLY WHAT I REALLY
EXPECT AND I THINK WHAT’S GREAT ABOUT THAT REPORT IS THAT
IT BROUGHT TOGETHER RESULTS FROM SO MANY DIFFERENT STUDIES,
DIFFERENT INVESTIGATORS, DIFFERENT COUNTRIES,
DIFFERENT METHODOLOGIES; AND SO WHEN YOU FIND THIS
CONVERSANT IT’S REALLY QUITE PERSUASIVE AND I
THINK THAT’S ONE OF THE LANDMARK STUDIES
THAT’S COME OUT IN THE LAST COUPLE OF YEARS.>>SO IF IT’S, IF IT’S
ROUGHLY FIFTY, FIFTY, THE RESEARCHERS SAID IT’S
BASICALLY A DRAW, IT’S BOTH AND IT COULD BE ONE
OR THE OTHER, BUT IT’S REALLY A
COMBINATION OF THE TWO. BUT KNOWING IT’S ABOUT FIFTY
PERCENT GENETICS, DOES THAT MEAN THAT TWINS THAT ARE
IDENTICAL TWINS THAT ARE RAISED APART STILL HAVE
ABOUT A FIFTY PERCENT CHANCE WITH TURNING OUT WITH THE
SAME PERSONALITY TRAITS?>>WELL WHAT [INAUDIBLE] THAT
MEANS IS THAT IT’S REALLY BASED ON POPULATIONS AROUND GROUPS AND SO ONE PARTICULAR
IDENTICAL PAIR COULD BE VERY, VERY MUCH ALIKE AND ONE
PARTICULAR IDENTICAL TWIN MIGHT BE VERY, VERY DIFFERENT. BUT IF YOU AVERAGE
THEM ALL TOGETHER, WHICH IS WHERE YOU’RE
REALLY GOING TO GET THE IMPORTANT
INFORMATION, IT ENDS UP BEING
ABOUT FIFTY PERCENT. REMEMBER THESE ESTIMATES
CALLED HERITABILITY OR DEGREE OF GENETIC INFLUENCE, ARE
DESCRIBING THE VARIATION FROM PERSON TO PERSON
IN A GROUP. IN THAT PARTICULAR INDIVIDUAL
YOU CAN’T SLICE APART THEIR PERSONALITY OR THEIR ABILITY INTO A GENETIC ENVIRONMENTAL
COMPONENT. SO I WOULD SAY ON AVERAGE,
MOST IDENTICAL TWINS ARE GOING TO BE PRETTY MUCH ALIKE. THEY’RE NOT GOING
TO BE EXACTLY ALIKE; SOME PAIRS WILL BE
MORE ALIKE THAN OTHERS. FRATERNAL TWINS SAME THING;
THEY MIGHT BE VERY MUCH ALIKE IN SOME TRAITS, VERY DIFFERENT
THAN OTHERS, BUT OVERALL, IDENTICALS AS A GROUP WILL BE
MORE ALIKE THAN FRATERNAL TWINS.>>ON THAT NOTE, WE HAVE TO
GO TO A BREAK; STAY WITH US. AFTER THE BREAK WE’LL
CONTINUE THIS CONVERSATION ABOUT TWIN STUDIES. IT’S FASCINATING AND IT’S GOING TO GET EVEN MORE
FASCINATING; SO STAY WITH US. [ MUSIC ]>>[INAUDIBLE] THINK LIKE
NEEDLE FREE DIABETES CARE, ROBOTIC CHECKUPS,
ELECTRONIC ASPIRIN. THE ANSWER, BIOMEDICAL
ENGINEERS. IT IS ONE OF THE MOST
RAPIDLY GROWING CAREER FIELDS IN THE UNITED STATES. THESE PEOPLE ANALYZE AND
DESIGN SOLUTIONS TO PROBLEMS IN MEDICINE AND BIOLOGY; IMPROVING THE QUALITY
OF PATIENT CARE. WITH A DEGREE FROM CAL STATE
LONG BEACH YOU CAN BECOME A PART OF THIS AMAZING CAREER FIELD. [ MUSIC ]>>WELCOME BACK TO TALKING
POINTS, I’M DAVE KELLY AND MY GUEST TODAY
IS DOCTOR NANCY SEGAL AND NANCY BEFORE THE
BREAK, I SAID IT’S GOING TO GET EVEN MORE FASCINATING AS
WE DELVE INTO THIS EVEN MORE. WE’VE KIND OF ESTABLISHED
THE SCIENCE OF ALL OF THIS, NOW WE CAN TALK ABOUT
SPECIFIC TRAITS AND HOW THOSE TRAITS DEVELOP
OVER TIME AND CHARACTERISTICS. AND I WANT TO TALK A LITTLE
BIT MORE ABOUT FRATERNAL TWINS. FRATERNAL TWINS OF COURSE ARE
TWO SEPARATELY FERTILIZED EGGS, WHICH ARE INDEPENDENT
OF EACH OTHER; THEY’RE NOT THE IDENTICAL ONES. BUT THEY CAN ALSO HAVE
SOME SIMILARITIES AS WELL. AND I WANT TO TALK
ABOUT A PARTICULAR CASE THAT YOU FOUND THAT’S IN THE
GUINNESS BOOK OF WORLD RECORDS; I BELIEVE THEY WERE
FROM ENGLAND. AND THEY WERE BROUGHT TOGETHER AFTER SEVENTY EIGHT
YEARS OF BEING SEPARATED. HOW DID THAT HAPPEN AND
WHAT WERE THE RESULTS OF THAT REUNION.>>WELL THAT WAS ONE OF THE MOST
FASCINATING CASES I’VE EVER BEEN INVOLVED WITH DAVE. THESE WERE WOMEN
BORN IN ENGLAND, SEVENTY EIGHT YEARS AGO, AND ONE
MOVED TO THE U.S. WHEN SHE WAS IN HER TWENTIES AND
ALWAYS KNEW SHE WAS A TWIN, BECAUSE SHE WAS RAISED
BY THE BIOLOGICAL MOTHER; WHEREAS THE OTHER
ONE WAS ADOPTED AND HAD NO IDEA SHE WAS A TWIN. AND THEN THE DAUGHTER OF THE ONE
IN ENGLAND BEGAN TO DO A SEARCH FOR HER MOTHER’S GENEALOGY AND DISCOVERED HER MOTHER
WAS A TWIN; GOT IN TOUCH WITH HER MOTHER WAS LIVING
IN OREGON AND I WAS NOTIFIED AND I THOUGHT, HOW MARVELOUS TO BRING THEM TOGETHER
AND SO I DID. I BROUGHT THEM TOGETHER
AT CAL STATE FULLERTON AND IT WAS A WONDERFUL REUNION. THEY ARE THE WORLD’S LONGEST
SEPARATED PAIR OF TWINS, WHICH IS WHY THEIR RECORDS STILL
STANDS IN THE GUINNESS BOOK. WE BROUGHT THEM INTO MY
LABORATORY FOR A TWO DAY, VERY INTENSIVE ASSESSMENT
AND THE TWINS WERE ALIKE IN SOME WAYS, BUT DIFFERENT
IN OTHERS; THEIR ABILITIES, SOME OF THEIR INTERESTS
WERE QUITE DIFFERENT. BOTH OF THEM WERE SWIMMERS,
WHERE ONE TOOK UP SWIMMING AT A LATER AGE IN LIFE, BUT
THEY WERE I WOULD SAY VERY, VERY TYPICAL IN TERMS OF THEIR
SIMILARITY IN THE WHOLE SCHEME OF FRATERNAL TWINNING. WHAT WAS GREAT ABOUT THIS CASE
THOUGH WAS THEIR RELATIONSHIP. THE FACT THAT THEY MET
EACH OTHER AFTER THAT TIME; UNFORTUNATELY THEY
DIDN’T HAVE MUCH TIME TO DEVELOP THAT RELATIONSHIP. THEY WERE ONLY TOGETHER FOR
A COUPLE OF DAYS IN MY LAB; ABOUT A WEEK AT THE TWIN IN
OREGON AND THEN SEPARATED. FIVE MONTHS LATER, THE TWIN
FROM THE U.S. PASSED AWAY WHICH WAS VERY, VERY SAD. BUT THE ONE IN ENGLAND
ALWAYS SAID THAT SHE WAS SUCH SO GRATEFUL THAT SHE MET
HER TWIN AFTER ALL THESE YEARS. IT WAS A VERY SPECIAL
TIME FOR HER.>>WERE THEY ABLE TO
CATCH UP MEANINGFULLY FOR THOSE SEVENTY EIGHT YEARS?>>WELL I THINK THEY TRIED
THEIR BEST TO DO THAT. I THINK IT’S IMPOSSIBLE
TO COMPRESS A LIFE TIME OF EXPERIENCES INTO ONE
WEEK OF TIME TOGETHER, BUT I THINK THEY DID THEIR BEST.>>THAT BRINGS UP
ANOTHER INTERESTING TOPIC THAT YOU’VE BEEN
RESEARCHING AND THAT IS WHEN ONE TWIN LOSES ANOTHER
TWIN, OR LOSES THE OTHER AND SO UPON DEATH THE OTHER
TWIN IS LEFT WITHOUT THE OTHER. HOW DOES THAT AFFECT
THAT PERSON PHYCOLOGY?>>LOSING A TWIN IS ONE OF THE
MOST DEVASTATING LOSES THERE IS. AND I THINK THAT IT GETS UNDER
REPORTED AND UNDERREPRESENTED IN THE LITERATURE BECAUSE
PEOPLE TEND TO FOCUS ON THE LOSS OF A CHILD AND THE
LOSS OF A SPOUSE, WHICH OF COURSE ARE
CRITICAL AS WELL, BUT I’VE BEEN STUDYING THIS NOW
FOR PROBABLY TWENTY YEARS AND I OVER SEVEN HUNDRED CASES IN MY
STUDY, WHICH IS STILL ONGOING OF TWINS WHO LOST
A TWIN AS AN ADULT. AND WHAT WE FIND ARE TWO
THINGS; THAT THE IDENTICAL LOSS OR THE EXPERIENCE OF LOSING AN
IDENTICAL TWIN IS SOMEWHAT MORE DEVASTATING THAN A FRATERNAL,
WHICH MIRRORS THE KINDS OF RELATIONSHIPS THEY HAVE
WHEN THEY’RE TOGETHER. BUT WE ALSO FIND THAT THE LOSS OF A TWIN IS THE MOST
DEVASTATING RELATIVE TO OTHER RELATIVES, SUCH AS
PARENTS, NON-TWIN SIBLINGS, ETC. THE ONLY RELATIONSHIP
I CANNOT COMPARE IS THE LOSS OF A CHILD AND I’M VERY GRATEFUL
I CAN’T, BECAUSE I DON’T ANYONE TO LOSE THEIR CHILDREN. ANOTHER FASCINATING THING
IS THAT A SMALL NUMBER OF THOSE TWINS ALSO
LOST SPOUSES. AND THE LOSS OF A SPOUSE SEEMS
TO BE WAY UP THERE WITH THE LOSS OF A TWIN, WHICH I THINK
REALLY, UNDERLINES THE IMPORTANT OF LOSING A TWIN; AND HOW
BEREAVEMENT COUNSELORS REALLY NEED TO PAY GREATER ATTENTION TO
THE UNIQUE ASPECT OF THAT LOSS.>>IT ALSO SAYS A
LOT ABOUT EMOTIONAL AND PSYCHOLOGICAL
BONDING I GUESS.>>IT DOES BECAUSE IT’S A
VERY STRONG BOND PARTICULARLY BETWEEN THOSE IDENTICAL TWINS AND BETWEEN SOME
OF THE FRATERNALS. AND SO THE LOSS OF THAT BOND
SOMEONE WHO’VE KNOWN ALL YOUR LIFE IS REALLY QUITE DEVASTATING AND IN FACT SOME SPECIALIZED
SUPPORT GROUPS HAVE EVOLVED JUST TO HELP THOSE TWINS GET
THROUGH THAT EXPERIENCE.>>SO IS THERE A FEELING
OF BEING INCOMPLETE SOMEHOW WITH THE LOSS OF THE TWIN?>>WELL THAT’S ONE
OF THE CONSEQUENCES, FEELING INCOMPLETE, BIRTHDAY’S
BECOME DEVASTATING DAYS, HOLIDAYS, ANY IMPORTANT
SIGNIFICANT DAY BECOMES A DAY OF A LACK OF CELEBRATION AS
BEFORE IT WAS CELEBRATED.>>ALRIGHT LET’S TALK ABOUT
SOMETHING THAT’S A LITTLE BIT, A LITTLE BIT LESS MORBID BECAUSE
IT DOESN’T INVOLVE DEATH; IT INVOLVES TALENT
THAT TWINS HAVE. LET’S SAY THE TWINS ARE BORN
WITH A GENETIC PREDISPOSITION FOR MUSICAL TALENT FOR EXAMPLE. IF THEY ARE RAISED APART
FOR WHATEVER REASON AND ONE HOME IS PARTICULARLY
GOOD AT PROMOTING MUSICAL
DEVELOPMENT OR MUSIC TALENT AND THE OTHER IS NOT, HOW WILL THAT POTENTIALLY
AFFECT THE TWINS?>>WELL IT COULD AFFECT
THEM IN A NUMBER OF WAYS AND IN FACT THE CASE
THAT YOU RAISE WAS ONE THAT WE STUDIED EXACTLY THE SAME
AT THE UNIVERSITY OF MINNESOTA. ONE OF THE WOMEN WAS RAISED
IN A HOME PLAYING THE PIANO AND THERE WAS A LOT OF PRESSURE
ON HER TO BECOME VERY GOOD AND TO TRY TO PERHAPS,
GET INTO AN ORCHESTRA; WHEREAS THE OTHER ONE HAD
MUCH LESS PRESSURE ON HER. AND YET, THE ONE TWIN RAISED
WITH LESS PRESSURE ENDED UP BEING A CONCERT PIANIST AND THE OTHER ONE JUST
PRACTICED AS A HOBBY. WHAT’S INTERESTING IS THESE
ENVIRONMENTAL EVENTS ARE NON-SHARED BETWEEN THE TWINS AND
THEY WORK IN UNPREDICTABLE WAYS. YOU CAN IMAGE THAT THE TWIN WITH
MORE PRESSURE MIGHT HAVE GONE ON TO BE THE PIANIST, BUT
THAT WAS NOT THE CASE. THIS IS REALLY ONE OF THE
CHALLENGES THAT PEOPLE IN MY FIELD FACE WHEN IT
COMES TO TWIN RESEARCH.>>WELL THAT’S A WHOLE OTHER
DYNAMIC IS PARENTAL PRESSURE BECAUSE I HEARD A STORY RECENTLY ABOUT A MAJOR LEAGUE
BASEBALL PLAYER, NOT A TWIN, BUT A RELEVANT STORY HERE. AND THIS MAJOR LEAGUE
BASEBALL PLAYER NOW HAS A SON WHO IS PLAYING LITTLE LEAGUE. PEOPLE ALWAYS ASK HIM ARE YOU
GOING TO COACH YOUR SON NOW THAT HE IS PLAYING BASEBALL
AND HE CAN BECOME A BIG STAR AND THE PLAYER SAYS NO, NO,
I’M NOT GOING TO BE THE COACH. I GO INTO THE GRAND STAND
AND WATCH AND CHEER HIM ON; IF HE BECOMES A GREAT
BASEBALL PLAYER, TERRIFIC. IF NOT, I WANT TO MAINTAIN
THAT FATHER, SON RELATIONSHIP AND THE REASON’S BECAUSE HIS
OWN FATHER PUSHED HIM SO HARD IN A SINGLE MINDED FOCUS OF MAKING HIM A GREAT
BASEBALL PLAYER, THAT THE REST OF THAT RELATIONSHIP WITH HIS
OWN FATHER KIND OF FELL APART.>>WELL I THINK THAT’S WHY, THAT BRINGS UP ANOTHER
INTERESTING POINT ABOUT WHERE TALENT COMES FROM
AND OF COURSE, ONE COULD SAY IN THAT CASE, THAT THE YOUNG
BOY MODELED HIS FATHER AND GOT INTO BASEBALL BECAUSE OF THAT. BUT ON THE OTHER HAND THE
FATHER PASSES ON THE GENES THAT ARE CONDUCIVE TO
GREAT ATHLETIC SKILL, IT’S ALL CONFOUNDED THERE. AND THAT’S WHY INTACT BIOLOGICAL
FAMILIES ARE NOT GOOD FOR TAKING OUT ENVIRONMENT EFFECTS. THAT’S WHY WE’VE
TURNED TO TWIN STUDIES, PARTICULARLY TWINS RAISED APART AND ALSO STUDIES OF
ADOPTED CHILDREN. THEY’RE EXCELLENT FOR LOOKING
AT THESE KINDS OF THINGS.>>OK, WELL LET’S, LET’S TAKE A
LOOK AT ANOTHER AREA OF RESEARCH THAT YOU’RE FOCUSING ON AS WELL
AND THAT SAID TWINS FROM CHINA THAT WERE SEPARATED BECAUSE OF
THE ONE CHILD POLICY IN CHINA, SO YOU’RE STARTED STUDYING THAT. YOU HAVE SOME PRELIMINARY
RESULTS, WHAT ARE THOSE RESULTS
TELLING YOU?>>I’VE BEEN STUDYING AND
TRACKING THE DEVELOPMENT OF YOUNG TWIN, MOSTLY GIRLS,
WHO HAVE BEEN ABANDONED THROUGH THE ONE CHILD POLICY
AND FIND THEMSELVES ADOPTED BY DIFFERENT FAMILIES. AND IT TURNS OUT THAT
WHEN THESE CHILDREN MEET, AS THE MOTHER’S REPORT, THESE CHILDREN FEEL ENORMOUSLY
ATTRACTED TO EACH OTHER. AND GET ALONG BETTER THAN
THEY’VE SEEN THEM GET ALONG WITH FRIENDS AT SCHOOL AND I
FIND THAT QUITE FASCINATING. AND I BELIEVE THAT IT’S PROBABLY
THE PERCEPTIONS OF SIMILARITIES THAT ARE DRAWING THEM TOGETHER
AND KEEPING THEM TOGETHER. NOW I’VE NOT YET
SEPARATED IT BY IDENTICAL AND FRATERNAL, I
HAVE TOO FEW CASES. BUT I THINK THAT WHEN I
DO I WILL BE ABLE TO SEE IF THOSE TWINS MIRROR WHAT WE’RE
SEEING IN ADULT TORN APART TWINS AND IN ADULT AND CHILDHOOD TWINS
WHO’VE BEEN RAISED TOGETHER.>>WELL FROM A STRICTLY
SCIENTIFIC POINT OF VIEW OR ACADEMIC POINT OF VIEW, ARE THERE DIFFERENT PROTOCOLS
YOU USE WHEN STUDYING IDENTICALS VERSUS FRATERNAL TWINS.>>NO I USE EXACTLY
THE SAME PROTOCOLS. EVERYTHING HAS TO
BE EXACTLY THE SAME SO YOU CAN MAKE THE
RELEVANT COMPARISONS.>>OK, AND SO WE’VE BEEN TALKING ABOUT THIS THROUGHOUT
THE PROGRAM, BUT BASICALLY TWINS ARE
GREAT LABORATORY IF YOU WILL.>>OH THE BEST.>>FOR STUDYING HUMAN TRAITS
AND BEHAVIOR, BOTH THE NATURE AND THE NURTURE SIDE
OF THE EQUATION. SO HOW DO WE EXTRAPOLATE
A GREATER TRUTH TO APPLY TO THE GENERAL POPULATION?>>WELL IF YOU DISCOVER THAT
SAY ALCOHOLISM HAS A GENETIC COMPONENT TO IT OR ANXIETY,
WHICH IS WHAT WE FOUND AND THEN YOU CAN
USE THAT INFORMATION TO COUNSEL FAMILIES WHETHER
INDIVIDUALS PREDISPOSED TO ALCOHOLISM OR TO ANXIETY. SO IF YOU KNOW IF A CHILD HAS
A PREDISPOSITION TO ALCOHOLISM, YOU MAKE SURE THAT THEY
STAY AWAY FROM ALCOHOL, DRUGS OR ALCOHOLIC BEVERAGES
AND IF THEY DO ENGAGE IN THEM, WELL IN MODERATION, VERY
CAREFULLY MODERATED. IF YOU’RE PRONE TO ANXIETY
THEN YOU WANT TO TRY TO MAKE DECISIONS THAT PUT
YOU INTO CALMER SITUATIONS; AVOID ANXIETY PROVOKING
SITUATIONS; REALLY GET A HANDLE ON WHAT CREATES THESE
KINDS OF BEHAVIORS. AS I SAID EARLIER, TWIN
RESEARCH IS NOT JUST FOR TWINS, IT’S FOR THE GREATER GOOD. NOW THERE IS A SEGMENT
OF TWIN RESEARCH THAT IS PARTICULAR TO TWINS. DO YOU PUT THEM IN
THE SAME CLASSROOM? DO YOU DRESS THEM ALIKE? DO YOU MAKE SURE THEY GO TO
THE SAME BIRTHDAY PARTIES? THAT’S SOMETHING
TOTALLY DIFFERENT AND I THINK THAT’S A VERY VALID AND VERY IMPORTANT
AREA OF RESEARCH. BUT I TOOK IT BACK
AND FORTH IN BOTH. I THINK THAT BOTH ARE
EXTREMELY IMPORTANT.>>WELL LET’S TALK
ABOUT THE CONCEPT OF UNRELATED LOOK A LIKES. THESE ARE PEOPLE THAT
LOOK VERY SIMILAR; AND THEY’RE BROUGHT
TOGETHER; THERE ARE FOLKS THAT HAVE BROUGHT THEM TOGETHER
FOR PHOTOGRAPHY SESSIONS AND SO ON AND A LOT OF PEOPLE
KIND OF ASSUME THAT WELL, THEY LOOK ALIKE, SO
THEY PROBABLY ACT ALIKE AND HAVE SIMILAR TRAITS
BASED ON APPEARANCE. BUT YOUR RESEARCH FINDS THAT
THAT REALLY NOT THE CASE.>>I’VE BLOWN THAT
ONE OUT OF THE WATER. WELL I HAVE BEEN LUCKY TO GET
ACCESS TO SAMPLES OF PEOPLE WHO LOOK ALIKE, GENETICALLY
UNRELATED AND I FIND THAT THEY ARE VERY DIFFERENT
IN PERSONALITY AND SELF-ESTEEM. AND I THINK THAT MANY
PEOPLE ASSUME AS YOU SAID, IF YOU LOOK ALIKE YOU’RE GOING
TO BE TREATED A CERTAIN WAY, BUT THAT REALLY SHOWS
THAT THAT’S NOT THE CASE. NOW THAT’S AN IMPORTANT
THING THAT I FOUND BECAUSE MANY PEOPLE SAY THAT
IDENTICAL TWINS ARE ALIKE BECAUSE OF THEIR
SIMILAR FEATURES AND THE WAY PEOPLE TREAT THEM. IT IS TRUE THAT PEOPLE
TREAT IDENTICAL TWINS ALIKE, BUT IT’S BECAUSE IDENTICAL
TWINS BEHAVIORS EVOKE THAT SIMILAR TREATMENT. RIGHT? AND IF THAT WERE NOT THE
CASE, THE LOOK A LIKES SHOULD BE AS ALIKE AS THE IDENTICALS
AND WE FIND THAT THEY SIMPLY ARE NOT.>>WE’RE RUNNING OUT OF TIME
NANCY UNFORTUNATELY THE TIME PASSES SO QUICKLY WHEN WE
HAVE THESE CONVERSATION, BUT I’D LIKE YOU TO NARROW DOWN
YOUR RESEARCH INTO A COUPLE OF MAJOR THEMES FOR
OUR AUDIENCE. AND IF YOU COULD INSTILL
THIS MOUNTAIN OF RESEARCH THAT YOU’VE ACCUMULATED,
WHAT ARE THOSE MAJOR THEMES?>>THE MAJOR THEME IS
THAT GENETIC IS PERVASIVE, THAT IS IT AFFECTS VIRTUALLY
EVERY MEASURED TRAIT. THE DEGREE OF INFLUENCE MAY
VARY FROM TRAIT TO TRAIT, HIGHER SAY IN HEIGHT AND WEIGHT,
LOWER IN JOB SATISFACTION, IN THE MIDDLE FOR PERSONALITY, BUT IT AFFECTS EVERY
MEASURED TRAIT. ANOTHER POINT IS THAT SHARING
AN ENVIRONMENT WITH SOMEBODY, GROWING UP WITH SOMEBODY
DOES NOT MAKE YOU ALIKE. WHAT MAKE YOU ALIKE
IS THE SHARED GENES. WE KNOW THAT BECAUSE IDENTICAL
TWINS RAISED APART ARE AS ALIKE IN PERSONALITY AS IDENTICAL
TWINS RAISED TOGETHER. AND WE HAVEN’T GOTTEN TO
MY STUDY ON VIRTUAL TWINS, WHICH ARE INDIVIDUALS WHO ARE
THE SAME AGE AND RAISED TOGETHER IN THE SAME HOME, SO
THEY’RE TWIN LIKE IN NATURE WITHOUT BEING TWINS AND THEY
ARE VERY, VERY DIFFERENT. SO WHEN WE HAVE THESE
DIFFERENT STUDIES POINTING TO THE SAME RESULT, I THINK
WE CAN PRETTY CONFIDENT THAT WE FOUND SOMETHING
WORTH LOOKING AT.>>WE HAVE THIRTY SECONDS LEFT. YOU HAVE A COUPLE OF BOOK
PROJECTS IN THE WORKS. WHAT ARE THOSE PROJECTS?>>THE FIRST ONE; TWIN
MISCONCEPTIONS; SEVENTY BELIEFS ABOUT TWINS; I EVALUATE THEM,
ARE THEY TRUE, ARE THEY FALSE, WHAT’S THE SHORT ANSWER,
WHAT’S THE LONG ANSWER. THAT’S COMING OUT
SOMETIME EARLY NEXT YEAR. AND I’M WORKING ON A BOOK AT
THE SWITCHED AT BIRTH TWINS FROM BOG TOCK COLUMBIA,
WHICH WILL ALSO BE OUT SOMETIME LATER NEXT YEAR.>>THAT’S GREAT. WE’LL LOOK FORWARD TO
THOSE PUBLICATIONS.>>THANK YOU.>>THANK YOU FOR
BEING WITH US TODAY.>>MY PLEASURE DAVE.>>AND THANK YOU FOR JOINING US FOR THIS ADDITION
OF TALKING POINTS. JOIN US AGAIN SOON
FOR THE NEXT EPISODE. UNTIL THEN, I’M DAVE
KELLY, HAVE A NICE DAY.

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