Richard L. Michalski

GRANDPARENTAL INVESTMENT AS A FUNCTION OF RELATIONAL UNCERTAINTY AND EMOTIONAL CLOSENESS WITH PARENTS

Several theoretical perspectives have generated research on grandparental investment, notably socialization and evolutionary psychological perspectives. Using data collected from more than 200 older adults (mean age 67 years), we test three hypotheses derived from socialization and evolutionary perspectives about grandparents’ relationships with and investment in grandchildren. Results indicate that (1) emotional closeness with both children and children-in-law is positively related to reports of emotional closeness with grandchildren; (2) maternal grandmothers invest more in grandchildren than do other grandparents; and (3) grandparents invest more in daughters’ children than in sons’ children. Discussion addresses limitations of self-report methodology in this context and situates the current findings within the body of research indicating the existence of psychological mechanisms designed to guide differential nepotism.

ROMANTIC JEALOUSY IN EARLY ADULTHOOD AND IN LATER LIFE

Young men are more distressed by a partner’s sexual infidelity, whereas young women are more distressed by a partner’s emotional infidelity. The present research investigated (a) whether the sex difference in jealousy replicates in an older sample, and (b) whether younger people differ from older people in their selection of the more distressing infidelity scenario. We presented forced-choice dilemmas to 202 older people (mean age = 67 years) and to 234 younger people (mean age = 20 years). The sex difference replicated in the older sample. In addition, older women were less likely than younger women to select a partner’s emotional infidelity as more distressing than a partner’s sexual infidelity. Discussion offers directions for future work on sex differences and age differences in jealousy.

Siblicide and Genetic Relatedness in Chicago, 1870-1930

Using a sample of siblicides committed in Chicago from 1870 through 1930, the authors tested two predictions heuristically guided by an evolutionary perspective. They predicted a greater proportion of siblicides of in-law siblings will be perpetrated by beatings, relative to the proportion of siblicides of full siblings. This difference did not reach statistical significance although it was in the predicted direction. They found, as predicted, that a significantly greater proportion of accidental deaths occurred with siblicides of full siblings relative to the proportion of siblicides of in-law siblings. Discussion addresses limitations of this research and the need for a national-level database that codes for the genetic relationship between the siblicide victim and offender to capitalize on greater statistical power.

Upset in response to a Sibling's partner's infidelities.

Using data collected from people with at least one brother and one sister, and consistent with an evolutionary perspective, we find that older men and women (a) are more upset by a brother’s partner’s sexual infidelity than by her emotional infidelity and (b) are more upset by a sister’s partner’s emotional infidelity than by his sexual infidelity. There were no effects of participant sex or sex of in-law on upset over a sibling’s partner’s infidelities, but there was an effect of participant sex on reports of upset over one’s own partner’s infidelities. The results suggest that the key variable among older participants is the sex of the sibling or, correspondingly, the sex of the sibling’s partner, as predicted from an evolutionary analysis of reproductive costs, and not the sex of the participant, as predicted from a socialization perspective. Discussion offers directions for future work on jealousy.

Measures of grandparental investment as a limiting factor in theoretical and empirical advancement

To refine our understanding of grandparental investment and its consequences, we need to understand what grandparents do for their grandchildren. Knowing the landscape of grandparental investment will facilitate a better understanding of the impact of grandparental investment on grandchildren and will allow inroads to be made in bridging the different levels of analysis.