The social scientific study of leadership: quo vadis?

Journal of Management, May-June, 1997 by Robert J. House, Ram N. Aditya

Leaders: Born or Made?

A natural implication of the trait approach to leadership is the notion that leaders are to a substantial extent born, not made. This raises the question as to whether personal abilities and traits relevant to the effective exercise of leadership are genetically influenced.

Among the most influential studies in heritability of personality traits is the continuing Minnesota Study of Twins Reared Apart, begun in 1979. In one recent report, Bouchard, Lykken, McGue, Segal, and Tellegen (1990) report heritability coefficients of as much as 78% for the g-factor in mental ability, and a mean of 50% for a wide variety of personality traits measured by the Multidimensional Personality Questionnaire and the California Personality Inventory, among other variables. These coefficients express the amount of variance attributable to heritability. They imply that, at least to the extent that these traits are correlated with effective leader behavior, the potential for leadership may be genetically influenced. Included in the traits measured are several that are similar to the ones described in the above section such as adjustment, achievement and affiliative orientation, desire for social influence, tendency to behave in a socialized or responsible manner, assertiveness, interpersonal sensitivity, and interpersonal flexibility.

There is a potential problem with twin studies, however. The environments provided to monozygotic (MZA) twins reared apart are presumed to be different. The heritability coefficients are obtained as a direct estimation from the MZA Twins Reared Apart correlation, under the assumption that for twins randomly placed for adoption in early infancy, variance in personalities is due to genetic heritage, rather than shared environmental experience. In fact, however, some of the subjects recruited for the Minnesota study are twins who approached the Minnesota Twins Family Study Center, having learned of the ongoing research. At the time of their participation in the study, such twins may have been in contact with each other from anywhere between a week to 20 years (Bouchard et al., 1990). This raises the possibility that some of the twins could have developed similar interests as a result of coming together, even if they had been raised in different environments. Bouchard et al. state that "Such marked behavioral similarities between reared apart MZA twins raise the question of correlated placement: were the twins' adoptive homes selected to be similar in trait-relevant features which, in turn, induced psychological similarity?" (italics ours). Thus, it is possible that at least some of the paired twins share common experiences which, in turn, account for a nontrivial proportion of their shared variance in trait scores. Lykken (personal communication) reports that the amount of co-variance in twins' environments, measured on trait-relevant features, has been found by the Minnesota twin study researchers to range from .04 to. 10, indicating that the extent of environmental similarity has a very modest effect on the overall findings of their research. With more sophisticated control over extraneous and environmental variables, twin studies offer the potential to substantially increase our understanding of the origins of leadership.