The following will explore the operation of evolved mechanisms connected with cycling fertility. I first address strategic shifts in women’s behavior near ovulation and hypothesize that certain behavioral shifts at high fertility reflect an increase in women’s intrasexual competition tactics when conception is most probable. A simulated, online shopping program was designed to track women’s spending patterns (at varying budgets) on clothing, undergarments, shoes, jewelry, and other fashion accessories – items that likely enhance a woman’s ability to attract a high quality mate and effectively compete with same-sex rivals. Additionally, a laboratory task was created to assess women’s likelihood of incurring a risk to appear more attractive and have access to more resources than same-sex peers. Studies 1-3 will explore the effect of fertility on women’s consumer behavior and the influence of same-sex peers on fertility-induced motivation to appear more attractive. Study 4 will further examine fertility-induced shifts in women’s intrasexual competitiveness by measuring context-specific risks women take to gain a positional advantage over same-sex peers. The current studies present new data that provide novel insights into human adaptations to cycling fertility and highlight important decision-making processes that guide women’s social competition within a variety of domains. / text