The role of childhood adversity in reproduction trajectory and interest in infants

Abstract

Life history theory posits that an organism accelerates reproductive timing in response to cues of a harsh external environment. Indeed early reproductive timing in human females, including early menarche, is associated with living in dangerous and deprived neighbourhoods, being poor, experiencing familial stress and parental absence. There is some evidence that adversity acts on reproductive timing through an increased interest in infants. Interest in infants is thought to be an adaptation for acquiring caretaking skills to ensure offspring survival. Compared to males, females display greater interest in infants, which peaks prior to reproductive viability and declines with age. My research investigated the relationship between childhood adversity, intended reproductive timing, menarche and interest in infants in females. I explored methods for measuring interest in infants using four tools: 1) a forced choice paper and pencil preference task (PT), 2) self-reported fondness for babies questionnaire item, 3) a computer based delayed recognition task (CPTT) and 4) a computer based attention task using eye tracking (ETT). All of the tools, except the ETT indicated increased interest in infant stimuli compared to adult or neutral stimuli. However, there were weak correlations between measures suggesting the construct of interest in infants is not easily defined. In a large school study I measured interest in infants using the PT, the CPTT and the self-reported questionnaire item along with childhood adversity and reproductive trajectories in a sample of adolescent girls. I found that girls who experienced greater adversity stated a younger ideal age at parenthood and experienced earlier menarche. However, contrary to my predictions, girls who experienced less adversity showed greater interest in infants on the preference task. Investing in offspring requires adequate resources and adversity indicates resource scarcity. Thus instead of a mechanism between childhood adversity and reproductive trajectory, it is possible interest in infants might be an indicator of future parental investment. These findings support theories that there is a sensitive period in childhood when children form parental investment strategies.