Darwin's Lovers: Evolutionary Perspectives on Romantic Love

Abstract

When this thesis started, almost nothing was known about the evolution of romantic love. To my knowledge, only one evolution-informed hypothesis about romantic love had been tested and the outdated, yet predominant evolutionary theory of romantic love was inaccurate and provided no details about the processes or mechanisms through which romantic love evolved. There was, by all accounts, a massive gap in the literature. My thesis provides the first focussed contribution to understanding the evolution of romantic love and starts to fill this gap. This contribution not only sheds light on the evolution of romantic love but also provides a new framework which future research would benefit from using. I am the progenitor of a new field of inquiry - the evolutionary history of romantic love. My thesis attempted to go some of the way to answer the question, "How did romantic love evolve?" There was a supplementary overarching question which it also considered, "Is an evolutionary approach useful in understanding romantic love?" Both of these questions were answered to some extent. The former by suggesting processes involved in the evolutionary history of romantic love (i.e., natural selection, sexual selection, and co-option), and the latter in the affirmative, by answering some big questions about romantic love. My original contributions to knowledge include articulation of the theory of co-opting mother-infant bonding in the evolutionary history of romantic love, an understanding of the relationship between the evolution of romantic love and territoriality, suggestions that romantic love may still be evolving, suggestions about the role of sexual and natural selection in the evolution of romantic love, validation of a new scale, evidence supporting the notion that salience of a loved one plays a role in activity of mechanisms that cause romantic love, and the creation of the largest dataset in the world of people experiencing romantic love. My thesis is multidisciplinary and interdisciplinary. It uses methods from biological anthropology and psychology to answer questions about the evolution of romantic love. It uses an overarching framework taken from ethology. Literature review and synthesis, theoretical formulation, phylogenetic analysis, surveying, and traditional and novel quantitative research methods were employed. My thesis was proposed at the height of the covid pandemic, and therefore was structured to be able to accommodate an uncertain and restricted research environment. As a result, no fieldwork was undertaken, but suitable approaches to data collection and analysis were used, including an online survey. Among the main findings of my thesis were: - Romantic love probably evolved by co-opting mother-infant bonding; - Evolution found novel ways of using existing mechanisms to create romantic love; - Romantic love (through natural and sexual selection) solved both the same and different adaptive challenges faced by females and males in our evolutionary history; - Variation exists in the expression of romantic love; and - Territoriality does not precede the evolution of social monogamy in non-human primates. The outcomes of my thesis are preliminary knowledge about the evolution of romantic love and an example of multidisciplinary and interdisciplinary evolutionary approaches promoting a better understanding of the phenomenon of romantic love.