A Prospective and Retrospective 10-Year Study of Altruism and Reproductive Success

Previous research has produced inconsistent findings regarding the role of altruism in mating success. This study sought to test whether altruism (charity/volunteer work) relates to number of offspring. A nationally representative sample of Australian adults was separated into those unlikely to have more children (n = 4,296; age >= 45 [women], age >= 55 [men], M-age = 68.9 +/- 11.0 years) and those likely to have more children (n = 4,724; age range = 18-44 [women], 18-54 [men], M-age = 32.8 +/- 10.5 years). Measures of altruism and number of children were taken at baseline and 10 years later. In the retrospective analysis of older adults, there was a very small effect size in the predicted direction, indicating that more altruistic adults had more children. In the prospective analysis of younger adults, higher levels of altruism related to a greater number of total children 10 years later, as well as a greater number of children conceived during those 10 years. Increases in altruism over 10 years also related to a greater number of total children and a greater number of children conceived during those 10 years. Effect sizes were small to very small in all instances. There were no sex moderation effects and analyses controlled for personality, medical difficulties in childbearing, and sociodemographic factors. These findings provide evidence that altruism has a role in reproductive success, and indicate that inconsistent findings in previous research might simply reflect the small (real-world) effect size.