Broadcast week starting: February 9, 2000
Nature? Or nurture? Twins may hold the answer. Identical twins raised apart report eerie similarities in lifestyle and preferences. Host Dr. Fred Goodwin, himself a twin, leads this exploration of the world of twin-ness. Guests include Dr. Nancy Segal, author of "Entwined Lives;" Dr. Thomas Bouchard, who directs the Minnesota Twin Study; Dr. Goodwin's twin brother Cliff; and two sets of identical twins, including brothers separated as infants and reunited after 40 years apart, along with "twin ambassadors" Debbie and Lisa Ganz. With commentary by John Hockenberry, father of twins Zoe and Olivia.
The hour begins as host Dr. Fred Goodwin chats with his fraternal twin brother, Cliff Goodwin, an actor, director and audition coach living in Greenwich Village in Manhattan. They discuss their similarities and differences, and ways in which their "twinship" affected them as children and throughout their lives.
We hear next from Tom Patterson and Steve Tazumi, twin brothers separated 40 years ago as infants in an orphanage in Japan and only recently reunited. Although raised in different kinds of families in different parts of the U.S., the twins found that they walked alike, talked alike, and even had scars from injuries they suffered on the same place on their body. They are both weight-lifters and have both owned a gym; they both married American women and they both gave their first child a Japanese name and their second an American name.
Next, Dr. Goodwin welcomes Dr. Nancy Segal, a leading expert in twins and twin studies. Dr. Segal is professor of developmental psychology and director of the Twin Studies Center at California State University at Fullerton. Herself a twin, Dr. Segal worked on the well-known Minnesota twin study for nine years. Her latest book, Entwined Lives, is a comprehensive look at twins and twin research.
Dr. Segal discusses ways in which the study of twins helps us understand the distinctions between nature and nurture in shaping particular individual traits. She talks about how twinning occurs in both identical and fraternal twins, and says we know much more about fraternal twinning. For example, it occurs most often in black mothers and least often among Asian mothers. It’s not always easy to tell where a set of twins are identical or fraternal, she says. Fraternal twins, because they are in fact siblings, can share many of the same characteristics in appearance. And identical twins can look quite dissimilar if one twin suffered deprivation of some type during pregnancy. She also discusses the affect of birth order, the significance of right- and left-handedness, and relationships between triplets and other multiples.
Drs. Goodwin and Segal take a call from Linda, in Pennsylvania, the mother of fraternal twins, who says that she was fascinated by the way her twin infants behaved almost as one being, playing with each others hands and feet and communicating with a look or a signal. Dr. Segal says that kind of relationship is more common with identical twins than fraternal twins, but does occur with fraternal twins to some degree or another. She discusses some of the latest insights about raising and educating twins, and says, for example, that many experts are re-thinking the idea that it’s important to split twins up in different classes. For some twins, support from their sibling may foster better adjustment to school life, she says.
Another caller, Lew, from California, tells a story about his identical twin, who took over Lew’s girlfriend under false pretenses when Lew was out of town, and later married her. Lew also asked whether there is evidence of psychic connections between twins. Dr. Segal suggests that there are so many genetic and behavioral similarities that one need not look beyond that for an explanation of simultaneous heart attacks or similar attire on a particular day.
Dr. Segal also discusses her latest research, which is examining “pseudo-twins,” children adopted into the same family environment and raised together, sharing no genes. They are the opposite of twins, she says, and should provide further insight about the impact of genes versus the environment.
Click here for more information about Dr. Segal’s book Entwined Lives, including reviews, or to order it .
Next, we hear from Lisa and Debbie Ganz, twin sisters and co-authors of the Book of Twins book and calendar. They talk about their restaurant, also called “Twins,” soon to re-open in Times Square in New York, with a staff consisting entirely of identical twins, and about their twins’ referral and help line, 1-800-RU-Twins. You can learn more about the Ganz sisters and their work by visiting their website www.twinsworld.com. Click here for more information about their book and calendar or to order them.
Dr. Thomas Bouchard, professor of psychology at the University of Minnesota and director of the Minnesota Study of Twins Reared Apart, is the next guest. The Minnesota Twin Study is a 20-year psychological and medical review of identical twins raised in different homes. The study has provided a huge body of critical information about the importance of genes and the environment in personality and behavior, as well as in the development of various illnesses.
Dr. Bouchard explains that the Minnesota research is actually a four-part study, looking at identical twins raised together and identical twins raised apart, and also at fraternal twins raised both apart and together. Comparisons to date indicate that the vast majority of measured individual traits, like personality and attitude, are due to a genetic effect. That was unexpected, he says; most researchers expected there would be more of a variance with some characteristics being strongly genetic and others strongly environmental.
He says he found it particularly surprising that religion showed up as having a stronger-than-average genetic link. He also discusses the heritability of mannerisms, job choice, happiness and choice of a mate. Genes appear to have little effect on choice of a mate, he says, probably because the pool of potential mates at the time of selection is too limited to allow for similar choices.
The Minnesota study is near completion and will likely have data from 78 pairs of identical twins raised apart. Dr. Bouchard is analyzing data and preparing material for a book about his research.
Finally, commentator John Hockenberry looks at the “thermonuclear” world of his two-year-old twin girls, Zoe and Olivia.
Additional information about twins is available through: the Twins Foundation (general information, resources and links); "Mothers of Twins Clubs (parenting twins) and Twins Magazine periodical publication about and for twins).
