Fusional reserves and psychological variables in monozygotic twins

Following a suggestion of Gedda and Bérard-Magistretti, intra-pair differences between MZ twins in fusional reserves were compared with differences in psychological variables. While the strong relationship between twin leadership and FR which these workers found in twin children was not confirmed in the present small sample of 14 adult pairs, the twin with the higher FR tended to be the more introverted, the more intelligent and the one who volunteered for the investigation. He also tended to be the taller and the first born.

Further studies, including the temporal reliability of scores of fusional convergence, are required before the value of this characteristic as a psychological criterion can be established.