AbstractWork in behavioural ecology has been and continues to be highly informative in the study of human reproductive variation and behavioural flexibility. The traditional focus of this approach has largely been on calibrations in reproductive behaviour in ultimate terms (i.e. a specific behaviour is adaptive and maximizes fitness in different environments). Yet, understanding the ultimate function of human behaviour as adaptive to local environments allows for the deeper study of the proximate psychological, social and physiological mechanisms that can shift both reproductive timing and corresponding reproductive ideals, giving greater insight into the factors that influence early childbearing. Therefore, in the thesis I aim to explore and confirm some of the mechanisms that impact on male and female reproductive timing.
Firstly, I demonstrate that the impacts of social and environmental stressors such as the local sex ratio result in different response patterns from women with different socioeconomic backgrounds, the implication being that women with different life history trajectories have different strategic responses to environmental conditions in line with the predictions of life history theory. Secondly, I show that individuals’ subjective perceptions of their environment are just as important, and potentially more important, indicators of their fertility intentions than the often used objective indicators of environment quality such as deprivation. Thirdly, I show that individuals take risks in strategic ways that can be explained by evolutionary principles and that their future reproductive intentions are supported by pro-natal norms and are not due to deficiencies in their knowledge of safe sexual practice. Fourthly, I consider the evidence that kin networks help shape individuals’ psychology around life history strategies. Finally, I explore the causal pathways by which acute stress shifts individuals’ life history strategies and how this adjustment is moderated by an individual’s exposure to chronic childhood stressors.
The findings resulting from this work merges with other research in the field of behavioural ecology, moving towards an integrated understanding of human reproductive and behavioural calibrations and exploring the ultimate and proximate questions of human reproductive variation. These findings highlight the importance of understanding life history trade-offs as central to reproductive scheduling. In addition it provides policy makers and health workers with an alternative way of understanding early childbearing, one that sees human behaviour within its adaptive evolutionary context.
|Date of Award||Sep 2013|
|Supervisor||Ed Morrison (Supervisor), Paul Morris (Supervisor) & Bridget Waller (Supervisor)|