Satisfaction-Adaptation Principles in Sexual Desire 1 RUNNING HEAD: Satisfaction-Adaptation Principles in Sexual Desire Satisfaction-Adaptation Principles in Sexual Desire: Exploring Gender Differences across the Lifespan

Sexual desire may change according to two principles: the satisfaction principle (high sexual opportunity/frequency decreases sexual desire) and the adaptation principle (high sexual opportunity/frequency increases sexual desire). We explore the workings of these opposing principles separately for both genders across the adult lifespan. Two tests within a large (N = 181,546) and cross-cultural (11 countries) dataset revealed that the satisfaction principle accounts for sexual desire in men throughout the entire life and it accounts for sexual desire in women until their mid-30s. From that point onwards, however, the pattern of female sexual desire becomes increasingly consistent with the adaptation principle. What sets older women apart from younger women and men of all ages? We discuss several mechanisms, with a focus on the satisfaction principle’s evolutionary value in life phases of high reproductive capacity and the adaptation principle’s evolutionary value in life phases of low reproductive capacity.