Vol. 10, No. 1, 2004 Page 3
Psychotherapy is based largely on the idea that children's relationships with their parents affect their later adjustment in adulthood. A new study suggests, however, that the genetic makeup of the children themselves can significantly influence their memories of how they were raised.
Paul Lichtenstein and colleagues studied 150 pairs of identical (monozygotic) twins, and 176 pairs of fraternal (dizygotic) twins, all female. Because fraternal twins share only half as many genes as identical twins, differences between the two can be used to determine the effects of heredity.
The researchers asked the women to describe their own personal characteristics, and to report their memories of their relationships with their parents. "Quantitative genetic analysis showed moderate genetic influences for remembered parental warmth," they say, "which also was partly explained by genetic influences for optimism, aggression, and humor." Environmental influences, conversely, appeared to affect memories of whether parents were protective or authoritarian (although an earlier study by a different research group found modest effects of genetics on adults' recollections of parental protectiveness or authoritarianism).
Lichtenstein et al. say, "It is possible that these associations at least partly reflect the impact of the personal characteristics [of the child] upon parenting—in other words, humor and optimism elicited more parental warmth, aggression less." It is also possible, they say, that the personality traits of the children affected how they remembered their relationships with their parents. While circumstances in the subjects' adult lives could have affected their perceptions of parental warmth, the researchers say this was not consistent with their data.
"Remembered parental bonding in adult twins: genetic and environmental influences," Paul Lichtenstein, Jody Ganiban, Jenae M. Neiderhiser, Nancy L. Pedersen, Kjell Hansson, Marianne Cederblad, Olof Elthammar, and David Reiss, Behavior Genetics, Vol. 33, No. 4, July 2003, 397- 408. Address: Paul Lichtenstein, Department of Medical Epidemiology, Karolinska Institutet, Box 281, S-171 77 Stockholm, Sweden, paul.lichtenstein@mep.ki.se.