Doctoral Dissertation Improvement: Longitudinal Perspectives on Human Paternal Psychobiology in the Philippines

Northwestern University, Evanston IL

Investigators

Abstract

Research has shown that in some cultural settings fathers have lower testosterone levels than non-fathers. Because these studies have not documented changes in hormones over time as men transition into fatherhood, it is not clear whether men with low testosterone are more likely to become fathers, or alternatively, if having a child leads to hormonal changes in men, much as past research has shown in mothers. This study tests the hypothesis that men experience a reduction in testosterone and an increase in prolactin (a hormone related to nurturing behavior in mothers) after becoming fathers. This question will be evaluated in 850 men participating in a large community-based study in the Philippines. The second aim of the study is to assess whether providing care to children leads to immediate, short-term changes in these same hormones in a smaller sample of 60 of the same men. These men are asked to provide culturally-appropriate care for their child for 30 minutes. Hormones will be measured in saliva and fingertip dried blood samples before and after this interaction, allowing evaluation of whether hormones shift to a profile more compatible with nurturing behavior. By comparing hormone levels with detailed reports of men's fathering behaviors and their attitudes regarding fatherhood and childcare, this study will help clarify the nature of biological changes that men experience in specific contexts of fathering. These characteristics may be uniquely important in humans compared to many other mammals. This project also expands understanding of the ways in which behavior and biology differ across cultures by contributing important insights into the range of human diversity in fathering behaviors and their relationships to male hormonal profiles. Finally, the project fosters international research collaboration between scholars and universities in the Philippines and US.