In the Minnesota Study of Twins Reared Apart (Bouchard, Lykken, McGue, Segal, & Tellegen, 1990; Lykken, Bouchard, McGue, & Tellegen, 1992b), we too have been struck by the similarities in personal style within many of the MZA pairs whom we have studied over the past 12 years. While videotaping an interview with one twin, we discovered that he was an accomplished raconteur with a fund of amusing anecdotes, so, while interviewing the co-twin, we asked him if he knew any funny stories. “Why, sure,” he said, leaning back with a practiced air, “I'll tell you a story” and proceeded to demonstrate his concordance. A pair of British MZAs, who had met for the first time as adults just a month previously, both firmly refused in their separate interviews to express opinions on controversial topics; since long before they discovered each other's existence, each had resolutely avoided controversy. Another pair were both habitual gigglers, although each had been raised by adoptive parents whom they described as undemonstrative and dour, and neither had known anyone who laughed as freely as she did until finally she met her twin. Both members of another pair independently reported that they refrained from voting in political elections on the principle that they did not feel themselves well enough informed to make wise choices. A pair of male MZAs, at their first adult reunion, discovered that they both used Vademecum toothpaste, Canoe shaving lotion, Vitalis hair tonic, and Lucky Strike cigarettes. After that meeting, they exchanged birthday presents that crossed in the mail and proved to be identical choices, made independently in separate cities.
There were two “dog people” among the MZA individuals; one showed her dogs, and the other taught obedience classes—they were an MZA pair. Only two of the more than 200 individual twins reared apart were afraid to enter the acoustically shielded chamber used in our psychophysiology laboratory, but both separately agreed to continue if the door was wired open—they were a pair of MZA twins. When at the beach, both women had always insisted on entering the water backwards and then only up to their knees; they were thus concordant, not only in their phobic tendencies but also in the specific manifestations of that timidity. There were two gunsmith hobbyists among the group of twins; two women who habitually wore seven rings; two men who offered a (correct) diagnosis of a faulty wheel bearing on Bouchard's car; two who obsessively counted things; two who had been married five times; two captains of volunteer fire departments; two fashion designers; two who left little love notes around the house for their wives, … in each case, an MZA pair.
