Romantic Love and Sleep Variations: Potential Proximate Mechanisms and Evolutionary Functions

SIMPLE SUMMARY: Romantic love is a topic of immense interest to scientists and the general public. This article defines and describes romantic love and sleep. It then summarises what research says about sleep in people experiencing romantic love. People in love experience changes in their sleep. We explain why people in love may experience sleep changes and what evolutionary purpose they might serve. We suggest that we are not able to determine whether sleep changes are a result of evolution or a secondary consequence. We finish by suggesting ideas for future research. ABSTRACT: This article provides a narrative review of what is known about romantic love and sleep variations and provides possible explanations for the association. Romantic love and sleep are described using a comprehensive, unifying framework advocated by Tinbergen. We summarise the findings of studies investigating the relationship between romantic love and sleep. Sleep variations are associated with romantic love in adolescents and young adults. We then detail some proximate mechanisms that may contribute to sleep variations in people experiencing romantic love before considering potential evolutionary functions of sleep variations in people experiencing romantic love. The relationship between symptoms of psychopathology and sleep variations in people experiencing romantic love is described. With the current state of knowledge, it is not possible to determine whether sleep variations associated with romantic love are adaptations or by-products of romantic love. We conclude by proposing areas for future research.