MONTREAL — When twins have similar personalities, is it mainly because they share so much genetic material or because their physical resemblance makes other people treat them alike?
A study of look-alikes shows they don't necessarily act alike
Study of non-twins shows it's the DNA that creates similarities.
By DAVID LEVINE
August 30, 2014 at 9:32PM
Most researchers believe the former, but the proposition has been hard to prove. So Nancy L. Segal, a psychologist who directs the Twin Studies Center at California State University, Fullerton, decided to test it — and enlisted an unlikely ally.
François Brunelle, a photographer in Montreal, takes pictures of people who look alike but are not twins. Segal was sent to Brunelle's website by a graduate student who knew of her research with twins. When she saw the photographs, she realized that the unrelated look-alikes would be ideal study subjects: She could compare their similarities and differences to those of actual twins.
"I reasoned that if personality resides in the face, then unrelated look-alikes should be as similar in behavior as identical twins reared apart," she said. "Alternatively, if personality traits are influenced by genetic factors, then unrelated look-alikes should show negligible personality similarity."
For 14 years, Brunelle, 64, has been working on a project he calls "I'm Not a Look-Alike!"— more than 200 black-and-white portraits of pairs who look startlingly alike.
Most come to him through social media links to his website. "It has taken on a life of its own," he said. "I have heard from people in China — and even a man who has an uncle in Uzbekistan who is a dead ringer for former President George W. Bush."
Two of his subjects, Roniel Tessler and Garrett Levenbrook, met three years ago at the University of Michigan, where Levenbrook was a student and Tessler was visiting with an a cappella group from the University of Maryland. Mutual friends steered them to Brunelle's website.
When the two got together, at a pizza parlor in New York City, "we ordered the same toppings," said Levenbrook, 25. "I found it difficult at first to look at Roniel because I felt I was looking into a mirror."
But other than that, the two have little in common. Tessler, 27, describes himself as a free spirit; he called Levenbrook his "exact opposite" — "the most focused and organized person I know."
For Segal's initial study, she asked Brunelle to send questionnaires to some of his subjects, and she received completed forms from 23 pairs of unrelated look-alikes. The questionnaires measured stability, openness, extroversion, agreeableness and conscientiousness. The participants also took the Rosenberg Self-Esteem Scale, a widely used research measure.
As she expected, the unrelated look-alikes showed little similarity in personality or self-esteem. But twins — especially identical twins — score high on both scales, suggesting that the similarities were largely because of genetics. Her results were published in the journal Personality and Individual Differences.
