A new look at dehumanization: The association between menstrual cycle changes and dehumanization of women

Hormonal fluctuations across menstrual cycle affect women's sexuality, women's self- perception, women's self-presentation, women's mate preferences, and their attitudes towards other women. In particular, women in high-conception risk (i.e., the probability of pregnancy), compared to women in low-conception risk, are more willing to spend money for items that increase their appearance (e.g., Durante et al., 2011), more prone to dress skin- revealing clothes, and are judged to look more attractive by male and female raters (e.g., Haselton et al., 2007). Enhanced levels of conception risk are associated with competitive attitudes towards women on the attractiveness dimension (e.g., Fisher, 2004). These results likely reflect a self-promotion strategy that is rooted in intra-group comparisons along the dimensions of attractiveness. Research in social psychology shows that stressing the relevance of physical appearance and attractiveness of a target (e.g., Vaes et al., 2011) can lead to the dehumanization of this target (i.e., the denial of distinctively human features), and in particular of women. In the current thesis, I test the main hypothesis of a link between conception risk levels and the dehumanization of women. In Chapter 1, I present an overview of the physiology of the female menstrual cycle and I describe the possible methods to compute the likelihood of conception. In Chapter 2, I summarize research on behavioral and cognitive changes associated with menstrual cycle. Specifically, I address the question of whether high conception risk affects the importance women devote to their own and to other women's attractiveness. Moreover, I discuss research strands that analyze the importance women attribute to dominance-related cues in men. I discuss this evidence, according to evolutionary and social psychological perspectives. In Chapter 3, I summarize studies on the dehumanization, and I then outline whether and how focus on attractiveness and physical appearance lead to the dehumanization of women, but not of men. On the basis of this review of the literature, I will put forward the hypothesis that I will test in four studies. I demonstrate that the explicit and automatic dehumanization of other women increases as the conception risk is enhanced. Specifically, in Chapter 4, I show that the enhancement of conception risk, only in normally ovulating women, but not in hormonal-contraceptive users, is associated with the dehumanization of women, but neither of men (mating relevant target) nor of elderlies (mating irrelevant target). Moreover, I show that increased levels of conception risk led not only to the dehumanization of women but also to the enhancement of intra-sexual competition. In Chapter 5, I employ an unobtrusive technique of attitude assessment (i.e., semantic priming procedure) to replicate these effects. In Chapter 6, I replicated previous results (Chapter 4 and 5) and, by salivary assessment of estrogen and progesterone, I further explore the role of sex hormones in the relationship between menstrual cycle stages and the dehumanization of women.