Economic Decisions, Attractiveness, and Intrasexual Competition during Menstrual Cycle in the Ultimatum Game.

Introduction: it seems that, in the phase of greatest fertility, women's intrasexual competition (toward attractive women who live nearby) increases due to access to resources, status, and biologically desirable partners. Objective: to compare the economic decisions (ED) during the ovulatory (OP) and luteal (LP) phases of the menstrual cycle (MC) with exposure to two stimuli: a photograph of a more attractive woman and a photograph of a less attractive woman, through the ultimatum game (UG). Methodology: the research followed a cross-sectional design between subjects to see group differences by contrasting hypotheses. The sampling was probabilistic, with a sample of 100 heterosexual women, students at a public university with an age range of 18 to 24 years, with regular MC, who did not use hormonal contraceptive methods and did not have any endocrine condition. The inverse counting method with confirmation was applied to identify CM phases; and the UG to evaluate the DE. Results: the phases of the MC had no effect on the ED; the women behaved similarly in their decisions, regardless of the phase of the cycle they were in or the type of stimulus to which they were exposed. Conclusion: OP and LP do not affect the ED of women when they are exposed to an attractive stimulus. The discussion is made considering the evolutionary theory of the ovulatory shift hypothesis.

Introducción: parece ser que, en su fase de mayor fertilidad, la competencia intrasexual de la mujer (con mujeres atractivas y que viven cerca) aumenta por el acceso a recursos, estatus y parejas biológicamente deseables. Objetivo: comparar las decisiones económicas (DE) en las fases ovulatoria (FO) y lútea (FL) del ciclo menstrual (CM) con exposición a dos estímulos: fotografía de una mujer de mayor atractivo y fotografía de una mujer de menor atractivo, a través del juego del ultimátum (UG). Metodología: la investigación tuvo un diseño cross-sectional entre sujetos para ver diferencia de grupos mediante contraste de hipótesis. El muestreo fue probabilístico, con una muestra de 100 mujeres heterosexuales, estudiantes de una universidad pública con un rango de edad de 18 a 24 años, con CM regulares, que no usaran métodos anticonceptivos hormonales y no tuvieran ninguna afección endocrina. Resultados: las fases del CM no tuvieron efectos sobre las DE; las mujeres se comportaron de forma similar en sus decisiones, sin importar la fase del ciclo en la que se encontraban o el tipo de estímulo al que fueron expuestas. Conclusión: las FO y FL no afectan las DE de las mujeres cuando son expuestas a un estímulo atractivo. La discusión se hace a la luz de la teoría evolutiva de la hipótesis del cambio ovulatorio.

Intimate Partner Violence in Nicaragua: The Role of Possessive Jealousy, Intrasexual Competitiveness, Life History, Mate Value, and Stress.

Using an evolutionary perspective, we examined predictors of intimate partner violence (IPV) in the Department of the Rio San Juan in Nicaragua. Specifically, we focused on possessive jealousy, intrasexual competitiveness, life history strategy, mate value, and stress. The sample consisted of 199 men and 201 women (mean age = 36.48, SD = 10.47) from the general population who were all personally interviewed. For all variables, validated measures were used. The data were analyzed for men and women separately, using regression analyses. In contrast to previous research and our expectations, possessive jealousy was not related to IPV among men or women. Rather, among men, IPV was independently predicted by (a) intrasexual competitiveness, (b) a fast life history strategy, (c) a low mate value, and (d) stress, together explaining 35% of the variance. Among women, violence against one's partner was only predicted by intrasexual competitiveness (3% explained variance). These results suggest that perpetration of IPV in Nicaragua may have qualitative different roots among men than among women, and that for men, more "triggers" are present which may evoke aggression toward their partners. These results are discussed in light of their relevance for theory and practice.

Fear of Violence among Colombian Women Is Associated with Reduced Preferences for High-BMI Men.

Recent studies reveal that violence significantly contributes to explaining individual's facial preferences. Women who feel at higher risk of violence prefer less-masculine male faces. Given the importance of violence, we explore its influence on people's preferences for a different physical trait. Masculinity correlates positively with male strength and weight or body mass index (BMI). In fact, masculinity and BMI tend to load on the same component of trait perception. Therefore we predicted that individuals' perceptions of danger from violence will relate to preferences for facial cues to low-BMI. In two studies in Colombia, men and women from Bogota, Medellin, and surrounding communities were shown pairs of faces transformed to epitomize the shape correlates of men with high or low-BMI. The images were of European, Salvadoran, or Colombian men. Participants were asked to choose the face they considered most attractive. Subsequently, participants answered a survey about their health (e.g., frequency of illnesses the past year), media access (e.g., frequency of Internet use), education level (e.g., graduating from high school), and experiences/perceptions of violence in study 1 and about specific types of violence (public and domestic) in study 2. Results from both studies showed that women who experienced/perceived higher levels of violence preferred faces of low-BMI Salvadoran men. Preferences for low-BMI facial cues were significantly explained by violence (public or domestic), even after controlling for all other variables (including age, education, health, and media access). These results may reflect women's strategy to avoid male partners capable of inflicting harm.