Louisville Magazine is Louisville's city magazine, covering Louisville people, lifestyles, politics, sports, restaurants, entertainment and homes. Includes a monthly calendar of events.
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Putting K 2 2Together By Jenni Laidman The groundbreaking Louisville Twin Study, conducted between the years 1957 and 2002, continues to provide surprising data on not just twins but all of us. elly and Kathy put on matching outfits and waited for their annual birthday ritual to begin. In their quiet Southside neigh- borhood in the 1970s, the arrival of any taxicab was an event. And today the taxicab stopped at their house. Te two little girls tumbled into the cab with their mother, Janice Mingus, eager for several hours of games, puzzles and rapt adult attention. Later in the day, there would be individual packages of peanut butter crackers and other fare that held the status of special-occasion food in that decade. Te cab stopped at the corner of Floyd Street and Muhammad Ali Boulevard, and the trio walked to the door of a seven-story building where a woman waited to let them in. Greeting them warmly by name, she ushered them through the lobby. Kelly took note of the bulletin board covered with pictures of hundreds of other twins, ad- miring all the new babies as she walked by. Her picture and Kathy's were up there, too, as were photographs of her cousins. Over the years, a younger brother and sister and more cousins would look out at her from the display. Tese were the faces of the Louisville Twin Study, several hun- dred twins and their families who visited the University of Louisville Medical-Dental Research Building once a year and played for the scientists. Tey stacked blocks, pieced together puzzles and raced through memory tests. Tey told stories and heard stories, and as they grew older, they figured out that the mirror in the back of the room was a window. People were watching them. Today, identical twins Kathy Perry and Kelly Davidson are 42. What they didn't know those decades ago, and what even their mother could not have guessed, was how this annual trip contribut- ed to changing opinions about human nature. Tese children would be two small raindrops in the gradual erosion of an entrenched idea. [60] LOUISVILLE MAGAZINE 8.12 In 1969, when Kathy and Kelly were born, college psychology students were taught that we entered the world as blank slates. Gradually the world wrote upon us, etching a picture to which our natures contributed little. Tese days, when even your barber talks about her genetic proclivity to part your hair on one side and not the other, the idea that we come into the world as empty vessels seems quaint. But in the last half of the 20th century, the specter of World War II still shaded our thinking. It created a deep revulsion to the notion of inborn traits, a fear that ascribing behavior to biology could lead to thoughts of superior races, with horrifying possibilities — possibilities from which the world was still recovering. So espousing the idea that we are a product of our genes was, at best, viewed with suspicion, and at worst, vilified. E.O. Wilson, the Harvard biologist now revered for his insights into evolution, bio- diversity and species extinctions, in 1975 published a book called Sociobiology: Te New Synthesis. In the book's final chapter, Wilson argued that genes contributed to all human behavior. Tis provoked a torrent of outrage, including a letter to the New York Review of Books signed by 15 people, among them the well-known Harvard biologists Richard Lewontin and Stephen Jay Gould. Te letter drew parallels between Wilson's ideas and racist sterilization laws, as well as "the eugenics policies which led to the establishment of gas chambers in Nazi Germany." At a scientific meeting organized around the topic of genes and behavior three years later, some of Wilson's critics rushed into the conference room shouting, "Racist Wilson, you can't hide; we charge you with genocide." Tey poured ice water on his head. Te researchers at the Louisville Twin Study were a part of this intellectual ferment, although far from the Cambridge spotlight. "Nobody was going to take a flight to Louisville to pour cold water on my head," says Adam P. Matheny, who led the Louisville study for 14 years until his retirement in 2000. But the Louisville twin research helped push environment from the driver's seat in human development. Te studies that Matheny, his co-investigators and predecessors conducted were aimed directly at determining genetic influence. In fact, twin studies are a clever tool for separating the effects of environment from the effects of DNA. Because identical twins have identical genes, any trait or behavior shaped largely by genes will be more similar in identical twins than it is in fraternal &