television, think it’s funny to sneeze in a crowd of strangers, flush the toilet before using it, store rubber bands on their wrists, read magazines from back to front, dip buttered toast in their coffee. Oskar is domineering toward women and yells at his wife, which Jack did before he was separated. [Holden, 1980] Their scores on several psychological tests were very similar, and they struck the investigator as remarkably similar in temperament and tempo.Other pairs of monozygotic twins in the study likewise startled the observers with their similarities, not only in appearance and in test scores but also in mannerisms and dress. One pair of twins, raised in rather serious homes, giggled at almost everything. In fact, when they were interviewed, it was hard to gather information because every comment triggered peals of laughter. Another set of female twins, separated since infancy, arrived in Minnesota each wearing seven rings (on the same fingers) and three bracelets, a coincidence that likely was partly genetic. Their genes endowed both women with beautiful hands. But, it is quite possible that they both have genetic interest in attractive objects and in self-decoration. Some people like the feel of rings, bracelets, and such against their skin, while others do not-for reasons that could be related to the sense of touch, itself genetically influenced.Case after case in this study has produced similar findings of surprising “coincidences,” suggesting that genes affect a much greater number of characteristics than was previously suspected by most psychologists, including the leader of the Minnesota study, Tomas Bouchard. Bouchard now concludes that genetic variation is significant for “almost every behavioral trait so far investigated, from reaction time t religiosity” (Bouchard et al., 1994).Many researchers are astonished at the similarities they find in monozygotic twins raised separately (Lykken et al....
