Gaze properties of women judging the attractiveness of masculine and feminine male faces

Effects of estrogen on spatial navigation and memory

RATIONALE

Animal studies suggest that the so-called "female" hormone estrogen enhances spatial navigation and memory. This contradicts the observation that males generally out-perform females in spatial navigation and tasks involving spatial memory. A closer look at the vast number of studies actually reveals that performance differences are not so clear.

OBJECTIVES

To help clarify the unclear performance differences between men and women and the role of estrogen, we attempted to isolate organizational from activational effects of estrogen on spatial navigation and memory.

METHODS

In a double-blind, placebo-controlled study, we tested the effects of orally administered estradiol valerate (E2V) in healthy, young women in their low-hormone menstrual cycle phase, compared to healthy, young men. Participants performed several first-person, environmentally rich, 3-D computer games inspired by spatial navigation and memory paradigms in animal research.

RESULTS

We found navigation behavior suggesting that sex effects dominated any E2 effects with men performing better with allocentric strategies and women with egocentric strategies. Increased E2 levels did not lead to general improvements in spatial ability in either sex but to behavioral changes reflecting navigation flexibility.

CONCLUSION

Estrogen-driven differences in spatial cognition might be better characterized on a spectrum of navigation flexibility rather than by categorical performance measures or skills.

The role of hormones in attraction and visual attention to facial masculinity

The current study investigated the ovulatory shift hypothesis, which suggests that women prefer more masculine traits when estradiol is high, and progesterone is low (E/P ratio). The current study used an eye tracking paradigm to measure women's visual attention to facial masculinity across the menstrual cycle. Estradiol (E) and progesterone (P) were collected to determine if salivary biomarkers were associated with visual attention to masculine faces in a short- and long-term mating context. Women (N = 81) provided saliva samples at three time points throughout their menstrual cycle and were asked to rate and view men's faces that had been manipulated to appear feminine and masculine. Overall, masculine faces were viewed longer compared to feminine faces and this was moderated by mating context, where women viewed masculine faces longer for a long-term relationship. There was not any evidence suggesting that E/P ratio was associated with preferences for facial masculinity, but there was evidence to suggest that hormones were associated with visual attention to men in general. In line with sexual strategies theory, there was evidence to suggest that mating context and facial masculinity are important in mate choice; however, there was no evidence to suggest that women's mate choice was associated with shifts across the menstrual cycle.

Using video games to understand sex differences in attentional biases for weapons

Attentional biases for threatening stimuli of various kinds have been repeatedly demonstrated. More recently, sex differences in the strength of visual biases for weapons have been observed, with men exhibiting stronger biases than do women. In the current study we further explored this sex difference, by examining how immediate vicarious experience with weapons (via playing a violent video game compared to playing a non-violent video game) affected the visual attention for weapons. We found that the basic visual bias for weapons compared to non-weapons was replicated, as was the sex difference in the strength of this bias. We also observed that the context produced by playing a violent video game prior to the visual search task, produced some sex differences in responding that were not present after playing the nonviolent video game, providing modest evidence that men may be more prone to cognitive behavioural effects of violent video game play. Interestingly, there was some evidence that both sexes de-prioritised non-weapons during search after playing the violent, relative to the non-violent, video game. We recommend that future studies investigate the task dynamics that may have led to this effect.

Oxidative stress as a hidden cost of attractiveness in postmenopausal women

Perceived facial attractiveness, a putative marker of high biological fitness, is costly to maintain throughout a lifetime and may cause higher oxidative stress (OS). We investigated the association between the facial features of 97 postmenopausal women and their levels of OS biomarkers 8-hydroxy-2′-deoxyguanosine (8-OHdG), superoxide dismutase (Cu-Zn SOD), and thiobarbituric acid reactive substances (TBARS). In study 1, 966 judges rated the composites (facial averages) of women with higher OS as more attractive, healthier, younger, and less symmetric. In study 2, Geometric Morphometric analysis did not reveal significant differences in facial morphology depending on OS levels. In study 3, measured facial averageness and symmetry were weakly negatively related to 8-OHdG levels. Maintaining higher perceived facial attractiveness may be costly due to increased oxidative damage in the postmenopausal period. These costs may remain hidden during the reproductive period of life due to the protective mechanisms of oxidative shielding and revealed only after menopause when shielding has ceased.

Stability of women's facial shape throughout the menstrual cycle

Facial characteristics can serve as a cue for judgements of multiple human traits, from maternal tendencies, overall fertility to sexual openness. In this study, we tested previously found fluctuations in facial shape throughout the menstrual cycle. With methods more robust than those formerly used (larger sample size and detailed hormonal assessments determining the timing of the ovulation), we did not find significant changes in either of the three facial measurements conducted: symmetry, averageness and sexual dimorphism (all F ≤ 0.78, all partial η² ≤ 0.01, all p ≥ 0.542). After narrowing the sample to cycles that had a higher probability of being ovulatory (based on daily measurements of luteinizing hormone and oestradiol), the results remained non-significant (all F ≤ 1.20, all partial η² ≤ 0.03, all p ≥ 0.315). Our results (i) suggest that the previously found increased facial attractiveness of women in the most fertile phase of the menstrual cycle is not driven by changes in facial shape, but might instead stem from other changes in facial appearance, such as a more attractive skin tone; and (ii) underline the importance of replication of studies with new methods.

Sex differences and the effect of instruction on reorientation abilities by humans

This study examined whether differences in the amount of information provided to men and women, in the form of verbal instruction, influenced their encoding during a reorientation task. When a navigator needs to orient, featural (e.g., colour or texture) and geometry (e.g., metric information) are used to determine which direction to begin traveling. The current study used a spatial reorientation task to examine how men and women use featural and geometric cues and whether the content of the task's instructions influenced how these cues were used. Participants were trained to find a target location in a rectangular room with distinctive objects situated at each corner. Once the participants were accurately locating the target, various tests manipulating the spatial information were conducted. We found both men and women encoded the featural cues, and even though the features provided reliable information, participants generally showed an encoding of geometry. However, when participants were not provided with any information about the spatial aspects of the task in the instructions, they failed to encode geometry. We also found that women used distant featural cues as landmarks when the featural cue closest to the target was removed, whereas men did not. Yet, when the two types of cues were placed in conflict, both sexes weighed featural cues more heavily than geometric cues. The content of the task instructions also influenced how cues were relied upon in this conflict situation. Our results have important implications for our understanding of how spatial cues are used for reorientation.

Women's self-rated attraction to male faces does not correspond with physiological arousal

There has been little work to determine whether attractiveness ratings of faces correspond to sexual or more general attraction. We tested whether a measure of women’s physiological arousal (pupil diameter change) was correlated with ratings of men’s facial attractiveness. In Study 1, women rated the faces of men for whom we also measured salivary testosterone. They rated each face for attractiveness, and for desirability for friendship and long- and short-term romantic relationships. Pupil diameter change was not related to subjective ratings of attractiveness, but was positively correlated with the men’s testosterone. In Study 2 we compared women’s pupil diameter change in response to the faces of men with high versus low testosterone, as well as in response to non-facial images pre-rated as either sexually arousing or threatening. Pupil dilation was not affected by testosterone, and increased relatively more in response to sexually arousing than threatening images. We conclude that self-rated preferences may not provide a straightforward and direct assessment of sexual attraction. We argue that future work should identify the constructs that are tapped via attractiveness ratings of faces, and support the development of methodology which assesses objective sexual attraction.