Sex differences in attraction to familiar and unfamiliar opposite-sex faces: men prefer novelty and women prefer familiarity

The Great Porn Experiment V2.0: Sexual Arousal Reduces the Salience of Familiar Women When Heterosexual Men Judge Their Attractiveness

Pornography has become widely accessible in recent years due to its integration with the Internet, generating social scientific and moralistic debate on potential "media effects," given correlations between consumption and various sexual traits and behaviors. One popular public debate (Wilson, 2012) claimed that exposure to Internet pornography has addictive qualities that could impact men's sexual relationships, underpinned by the "Coolidge effect," where males are sexually motivated by the presence of novel mates. As claims about Internet and sexual addictions are scientifically controversial, we provide a direct experimental test of his proposal. Adapting a paradigm used to examine "Coolidge-like" effects in men, we examined the extent to which exposure to images of pornographic actresses altered men's attractiveness ratings of (1) familiar faces/bodies on second viewing and (2) familiar versus novel women's faces/bodies. Independent of slideshow content (pornographic versus clothed versions of same actress), heterosexual men were less attracted to familiar bodies, and homosexual men were less attracted to familiar women (faces and bodies), suggesting that mere visual exposure to attractive women moderated men's preferences. However, consistent with one of our preregistered predictions, heterosexual but not homosexual men's preferences for familiar versus novel women were moderated by slideshow content such that familiar women were less salient on the attractiveness dimension compared to novel women when sexual arousal was greater (pornographic versus clothed slideshows). In sum, our findings demonstrate that visual exposure/sexual arousal moderates attractiveness perceptions, albeit that much greater nuance is required considering earlier claims.

Experimental Evidence for Sex Differences in Sexual Variety Preferences: Support for the Coolidge Effect in Humans

We examined sex differences in preferences for sexual variety and novelty to determine whether the Coolidge effect plays a role in human sexuality. In two experimental studies that employed different manipulations, we found converging evidence that men showed a greater preference for variety in potential short-term mates than did women. In the first study, men (n = 281) were more likely than women (n = 353) to select a variety of mates when given the opportunity to distribute chances to have sex with different individuals in hypothetical situations. This sex difference was evident regardless of the targets' attractiveness and age. Further, men found it more appealing if their committed romantic/sexual partners frequently changed their physical appearance, while women reported that they modified their physical appearance more frequently than did men, potentially appealing to male desires for novelty. In the second study, when participants were given a hypothetical dating task using photographs of potential short-term mates, men (n = 40) were more likely than women (n = 56) to select a novel person to date. Collectively, these findings lend support to the idea that sex differences in preferences for sexual variety and novelty are a salient sex-specific evolved component of the repertoire of human mating strategies.

From likely to likable: The role of statistical typicality in human social assessment of faces

Humans readily form social impressions, such as attractiveness and trustworthiness, from a stranger's facial features. Understanding the provenance of these impressions has clear scientific importance and societal implications. Motivated by the efficient coding hypothesis of brain representation, as well as Claude Shannon's theoretical result that maximally efficient representational systems assign shorter codes to statistically more typical data (quantified as log likelihood), we suggest that social "liking" of faces increases with statistical typicality. Combining human behavioral data and computational modeling, we show that perceived attractiveness, trustworthiness, dominance, and valence of a face image linearly increase with its statistical typicality (log likelihood). We also show that statistical typicality can at least partially explain the role of symmetry in attractiveness perception. Additionally, by assuming that the brain focuses on a task-relevant subset of facial features and assessing log likelihood of a face using those features, our model can explain the "ugliness-in-averageness" effect found in social psychology, whereby otherwise attractive, intercategory faces diminish in attractiveness during a categorization task.

Foundations of Erobotics

Technology is giving rise to artificial erotic agents, which we call erobots (erôs + bot). Erobots, such as virtual or augmented partners, erotic chatbots, and sex robots, increasingly expose humans to the possibility of intimacy and sexuality with artificial agents. Their advent has sparked academic and public debates: some denounce their risks (e.g., promotion of harmful sociosexual norms), while others defend their potential benefits (e.g., health, education, and research applications). Yet, the scientific study of human-machine erotic interaction is limited; no comprehensive theoretical models have been proposed and the empirical literature remains scarce. The current research programs investigating erotic technologies tend to focus on the risks and benefits of erobots, rather than providing solutions to resolve the former and enhance the latter. Moreover, we feel that these programs underestimate how humans and machines unpredictably interact and co-evolve, as well as the influence of sociocultural processes on technological development and meaning attribution. To comprehensively explore human-machine erotic interaction and co-evolution, we argue that we need a new unified transdisciplinary field of research-grounded in sexuality and technology positive frameworks-focusing on human-erobot interaction and co-evolution as well as guiding the development of beneficial erotic machines. We call this field Erobotics. As a first contribution to this new discipline, this article defines Erobotics and its related concepts; proposes a model of human-erobot interaction and co-evolution; and suggests a path to design beneficial erotic machines that could mitigate risks and enhance human well-being.

Maximizing Tendencies in Marriage: Accentuating the Implications of Readily Observable Partner Characteristics for Intimates' Satisfaction

People differ in their tendencies to labor over decisions and to make choices that maximize their outcomes-a difference known as maximization. Here, we used two independent, 3-year longitudinal studies of newlywed couples to demonstrate that this individual difference in decision making has important implications for romantic relationships. Consistent with the idea that maximizers are more likely to compare their current romantic partners to potential alternative partners' readily observable qualities, such as their physical attractiveness and status, results demonstrated that intimates' maximization moderated the implications of these sex-differentiated variables for marital satisfaction. Specifically, maximizing men who had attractive (vs. unattractive) wives were more satisfied at the start of their marriages. Likewise, maximizing women who had high (vs. low) status husbands experienced less steep declines in satisfaction over time. These findings demonstrate that maximization has important implications for long-term romantic relationships by accentuating the effects of readily observable partner qualities on relationship outcomes.

Beauty is in the belief of the beholder: cognitive influences on the neural response to facial attractiveness

Judgments of facial attractiveness are central to decision-making in various domains, but little is known about the extent to which they are malleable. In this study, we used EEG/ERP methods to examine two novel influences on neural and subjective responses to facial attractiveness: an observer's expectation and repetition. In each trial of our task, participants viewed either an ordinary or attractive face. To alter expectations, the faces were preceded by a peer-rating that ostensibly reflected the overall attractiveness value assigned to that face by other individuals. To examine the impact of repetition, trials were presented twice throughout the experimental session. Results showed that participants' expectations about a person's attractiveness level powerfully altered both the neural response (i.e. the late positive potential; LPP) and self-reported attractiveness ratings. Intriguingly, repetition enhanced both the LPP and self-reported attractiveness as well. Exploratory analyses further suggested that both observer expectation and repetition modulated early neural responses (i.e. the early posterior negativity; EPN) elicited by facial attractiveness. Collectively, these results highlight novel influences on a core social judgment that underlies individuals' affective lives.

How Beauty Determines Gaze! Facial Attractiveness and Gaze Duration in Images of Real World Scenes

We showed that the looking time spent on faces is a valid covariate of beauty by testing the relation between facial attractiveness and gaze behavior. We presented natural scenes which always pictured two people, encompassing a wide range of facial attractiveness. Employing measurements of eye movements in a free viewing paradigm, we found a linear relation between facial attractiveness and gaze behavior: The more attractive the face, the longer and the more often it was looked at. In line with evolutionary approaches, the positive relation was particularly pronounced when participants viewed other sex faces.

Does Sexual Satisfaction Change With Relationship Duration?

Despite a large body of empirical literature on sexual satisfaction, its development over the course of a relationship is still unclear. Only a small number of studies, most of which have relied on cross-sectional data of convenience samples, have explicitly focused on relationship duration, and empirical evidence is mixed. We analyzed how sexual satisfaction changes over the course of a relationship using three waves of the German Family Panel study (pairfam). We concentrated our analyses on young and middle-aged heterosexual individuals in committed relationships (N = 2,814) and applied fixed effects regression models, which have the advantage of estimations based on changes within individuals over time. We found a positive development of sexual satisfaction in the first year of a relationship, followed by a steady decline. This pattern persisted even when controlling for the frequency of intercourse, although the effects were, in part, mediated by intercourse frequency. We explained the non-linear effect of relationship duration on sexual satisfaction with an initial learning effect regarding partner-specific sexual skills, which is then outweighed by a decline in passion at later stages of a relationship. Moreover, we found significant effects for the control variables of health status, intimacy in couple communication, and conflict style, as expected. In contrast to past research, however, cohabitation and marriage were not found to play a role for sexual satisfaction in our data. Further research is required to deepen the understanding of the reasons why sexual satisfaction changes with relationship duration.

Men's Preferences for Female Facial Femininity Decline With Age

OBJECTIVES

Women tend to have a smaller chin, fuller lips, and rounder eyes than men, due in part to the effects of estrogen. These features associated with facial femininity have been found to be positively associated with fertility. Although young men in their 20s typically judge facial femininity as more attractive than facial masculinity, at all ages, men with higher sexual desire and testosterone levels tend to show a marked preference for feminine faces. In the current study, we extend this research using a large cross-national sample to test the hypothesis that facial femininity preferences will be stronger among younger men than among older men. We also tested whether these preferences are influenced by self-reported sexual openness, national health indices, and gross national income.

METHOD

We quantified attractiveness judgments (i.e., preferences) among 2,125 heterosexual men (aged 17-73 years) for female faces that were manipulated to appear more or less feminine using a computer graphics program.

RESULTS

Facial femininity preferences decreased with age, being highest among men in their 30s and lowest among men in their 70s. This pattern was independent of men's sexual openness and cross-national variation in health and socioeconomic development.

DISCUSSION

Our study shows that men's preferences for facial femininity are age dependent. At the proximate level, differences in preferences could reflect age-related declines in testosterone levels. These age-related declines in preferences could benefit older men, who are less able to invest in mating effort, and thus may opt out of competition with younger men for mates with potentially higher fertility.

The Role of Breast Size and Areolar Pigmentation in Perceptions of Women's Sexual Attractiveness, Reproductive Health, Sexual Maturity, Maternal Nurturing Abilities, and Age

Women's breast morphology is thought to have evolved via sexual selection as a signal of maturity, health, and fecundity. While research demonstrates that breast morphology is important in men's judgments of women's attractiveness, it remains to be determined how perceptions might differ when considering a larger suite of mate relevant attributes. Here, we tested how variation in breast size and areolar pigmentation affected perceptions of women's sexual attractiveness, reproductive health, sexual maturity, maternal nurturing abilities, and age. Participants (100 men; 100 women) rated images of female torsos modeled to vary in breast size (very small, small, medium, and large) and areolar pigmentation (light, medium, and dark) for each of the five attributes listed above. Sexual attractiveness ratings increased linearly with breast size, but large breasts were not judged to be significantly more attractive than medium-sized breasts. Small and medium-sized breasts were rated as most attractive if they included light or medium colored areolae, whereas large breasts were more attractive if they had medium or dark areolae. Ratings for perceived age, sexual maturity, and nurturing ability also increased with breast size. Darkening the areolae reduced ratings of the reproductive health of medium and small breasts, whereas it increased ratings for large breasts. There were no significant sex differences in ratings of any of the perceptual measures. These results demonstrate that breast size and areolar pigmentation interact to determine ratings for a suite of sociosexual attributes, each of which may be relevant to mate choice in men and intra-sexual competition in women.

Negative frequency-dependent preferences and variation in male facial hair

Negative frequency-dependent sexual selection maintains striking polymorphisms in secondary sexual traits in several animal species. Here, we test whether frequency of beardedness modulates perceived attractiveness of men's facial hair, a secondary sexual trait subject to considerable cultural variation. We first showed participants a suite of faces, within which we manipulated the frequency of beard thicknesses and then measured preferences for four standard levels of beardedness. Women and men judged heavy stubble and full beards more attractive when presented in treatments where beards were rare than when they were common, with intermediate preferences when intermediate frequencies of beardedness were presented. Likewise, clean-shaven faces were least attractive when clean-shaven faces were most common and more attractive when rare. This pattern in preferences is consistent with negative frequency-dependent selection.

How do you say 'hello'? Personality impressions from brief novel voices

On hearing a novel voice, listeners readily form personality impressions of that speaker. Accurate or not, these impressions are known to affect subsequent interactions; yet the underlying psychological and acoustical bases remain poorly understood. Furthermore, hitherto studies have focussed on extended speech as opposed to analysing the instantaneous impressions we obtain from first experience. In this paper, through a mass online rating experiment, 320 participants rated 64 sub-second vocal utterances of the word ‘hello’ on one of 10 personality traits. We show that: (1) personality judgements of brief utterances from unfamiliar speakers are consistent across listeners; (2) a two-dimensional ‘social voice space’ with axes mapping Valence (Trust, Likeability) and Dominance, each driven by differing combinations of vocal acoustics, adequately summarises ratings in both male and female voices; and (3) a positive combination of Valence and Dominance results in increased perceived male vocal Attractiveness, whereas perceived female vocal Attractiveness is largely controlled by increasing Valence. Results are discussed in relation to the rapid evaluation of personality and, in turn, the intent of others, as being driven by survival mechanisms via approach or avoidance behaviours. These findings provide empirical bases for predicting personality impressions from acoustical analyses of short utterances and for generating desired personality impressions in artificial voices.