Nurture got a poke in the eye from nature last week, with the publication of a wide-ranging study of identical and fraternal twins that showed differences in certain attitudes are partly due to genetic factors.
James Olson and colleagues at the University of Western Ontario surveyed 336 pairs of adult Canadian twins, asking them detailed "attitude questions" ranging from their feelings toward the death penalty to their views on roller coasters. All the sets of twins had been raised together, so had been exposed to similar environmental influences when growing up. Questions followed a format of "My overall attitude to doing crossword puzzles is" and allowed answers from "extremely favorable" to "extremely unfavorable."
To identify which sorts of attitudes were more influenced by genetic factors, the researchers compared the responses from fraternal twins (141 pairs of same-sex siblings) with those from identical twins (195 pairs).