EPinOZ 2018

The inaugural meeting of ASHBE (the Australasian Society for Human Behaviour and Evolution), EPinOZ 2018, was held on 23 November, 2018.  The meeting was sponsored by Western Sydney University, and Frontiers.

Peter Jonason (WSU)

Organising Committee
Peter Jonason (WSU)
Ian Stephen (MQ)
Danielle Sulikowski (CSU)

Holiday Inn, Potts Point, NSW

Complete List of Abstracts

Mate preferences in intelligent and educated mates

Peter K Jonason (Western Sydney University)

There has been a recent surge of research on the role of intelligence in mate preferences. To advance this area of research, two online studies (N = 743) investigated the role of relative intelligence in mate choice and a third online study (N = 1306) evaluated the role of relative education in mate choice. In all studies, we manipulated the relative intelligence/education as opposed to absolute/objective rates (e.g., IQ) to test a self-referential heuristic to increase ecological validity and to test a nonlinear hypothesis. Across all three studies, no matter the mating context, women maintained desire to pair with men who were equal (as opposed to less) intelligence/education, with no differences in desirability of partners who were equal and more intelligent. In contrast, while men's mate preferences matched women's in the long-term context, it was in the short-term context that men diverged from women, rating a less intelligent target as more desirable as a short-term partner. In Study 2, we tested whether preferences for intelligent partners interacted with the physical attractiveness of the targets. We found that the physical attractiveness standards must be met (but not exceeded) before intelligence factored heavily in mate preferences; an effect strongest in short-term relationships. In Study 3, we held physical attractiveness constant to determine whether agreeableness in targets interacted with preferences for educated partners; it did not. Instead, target's agreeableness operated independently, suggesting both sexes want an agreeable partner in the long-term but men are more willing to tolerate disagreeable women for casual sex encounters than women are. Results are discussed in terms of experimental approaches to mate preferences and evolutionary models of sex differences in mating psychology.

* * *
Gay Genes and the Competitor Conversion Hypothesis

Douglas Roy (University of New South Wales)
Timothy Peterson (Macquarie University)

We briefly review adaptationist explanations for homosexual behaviour and introduce our own preliminary model to suggest how genes for exclusively homosexual behaviour can be favoured by Spite-selection. We assume that our model can apply in species that have already evolved (1) incest avoidance mechanisms (whereby mating efforts are directed towards genetically distant sexual partners); (2) fraternal birth-order effects (whereby a gene can bias the body it is in to becoming homosexual when he has many close male relatives); and (3) it is possible for non-homosexual males to be decoyed or "converted" to homosexual patterns of behaviour. Under these conditions, a gene promoting gay behaviour can be favoured by selection if its cost is offset by the benefit it confers to dormant copies of itself in brothers. In other words, selection may favour such a gene if, when it is in a younger brother, it causes the bearer to forego producing his own offspring and instead concentrate his resources on distracting or converting his siblings' competition for female mates. Evidence suggests that possible mechanisms of conversion involve various associative learning processes that operate in determining mate choice. Behavioural and genetic predictions are discussed. 

* * *
Skin texture and colour predict perceived health in Asian faces

Ian Stephen (Macquarie University, Australia)
Tan Kok Wei (University of Reading, Malaysia)
Bernard Tiddeman (University of Aberystwyth, UK)

Facial skin texture and colour play an important role in observers' judgments of apparent health and have been linked to aspects of physiological health, including fitness, immunity and fertility. However, most studies have focused on Caucasian populations. Here, we report two studies that investigate the contribution of skin texture and colour to the apparent health of Asian faces. In Study 1, homogenous skin texture, as measured by wavelet analysis, was found to positively predict ratings of apparent health of Asian faces. In study 2, homogenous skin texture and increased skin yellowness positively predicted rated health of Asian faces. This finding suggests that skin condition serves as an important cue for subjective judgements of health in Asian faces.

* * *
Life history theory and psychopathology

Phil Kavanagh (ISN Psychology)
Jessie E. Hurst (School of Psychology, Social Work and Social Policy; University of South Australia)
Bianca L. Kahl (School of Psychology, Social Work and Social Policy; University of South Australia)

There is little extant empirical literature examining the associations between life history strategies and symptoms of psychopathology. The current studies (N = 138 and 343) investigated the associations between life history strategies, including a number of environmental and physiological indicators, symptoms of psychopathology, and attachment in a sample from the general population and local mental health services. The results from the studies indicate those with a faster life strategy report greater levels of aggression and symptoms of psychopathology with mixed findings about the role of attachment. Implications for life history theory, conceptualising psychopathology, and future research directions are discussed.

* * *
Two sides to every face: signalling functions of facial asymmetry

Danielle Sulikowski (Charles Sturt University)

Highly symmetrical faces are frequently perceived as more attractive than less symmetrical faces.  This has been attributed to fluctuating asymmetry being perceived as a sign of developmental instability.  Some studies, however, have failed to find a relationship between facial asymmetry and actual health, casting doubt over this interpretation.  Previous investigations, however, have failed to properly differentiate between fluctuating facial asymmetry and the systematic structural laterality seen in the human face. Patterns of facial laterality differ systematically between the sexes, as well as between individuals, and likely serve their own signaling purposes, unrelated to developmental stability.  Across 7 studies structural facial asymmetry is shown to be sexually dimorphic, and to positively impact on ratings of attractiveness, trustworthiness, and health. This contrasts with fluctuating asymmetry, which impacts negatively on these traits.  Geometric-morphometric analyses reveal that patterns (as opposed to levels) of asymmetry can also predict substantial variance in self-report Dark Triad personality traits.

* * *
Sexual Morality: Evolutionary perspectives, individual differences, and cross cultural contexts.

Kelly Asao (ISN Psychology)
David Buss (The University of Texas at Austin)

Across several studies, I investigated people's intuitions about sexual morality in order to explain inter-individual variation in sexual moral norms. One major goal of this research program was to develop a reliable and valid measure of sexual morality: the Sexual Morality Inventory (SMI). After creating the SMI, the next goal was to determine if variation in sexual morality could be explained by evolutionary theorizing. Across two studies, I found support for evolutionary explanations of sexual morality. After controlling for all other variables, including religiosity and political orientation, I found that disgust sensitivity and mating strategy remained strong predictors of sexual morality across individuals in the US. A final goal was to determine whether leading evolutionary theories could predict cross-cultural variation in sexual morality. In collaboration with researchers in 37 countries, I discovered which sexual acts are universally moralized (e.g., incest and sexual coercion) and which vary greatly from culture to culture (e.g., short-term sex and same-sex). Collectively, this program of research suggests that an evolutionary perspective can provide insight into variation in sexual morality across individual and cultural contexts.

* * *
Testing the condition-dependent hypothesis for the Dark Triad traits

Ceylan Okan (Western Sydney University)
Peter K Jonason (Western Sydney University)
Anja Cengia (Humboldt University)
Emrah Özsoy (Sakarya University)

A primary contention of evolutionary models of the Dark Triad traits (i.e., narcissism, psychopathy, and Machiavellianism) is that they are adaptations for dealing with adverse socioecological circumstances. In this study (N = 557), we collected data from two countries that differ in socioecological conditions (i.e., Turkey and Australia) and measured (1) perceptions of a dangerous and competitive world and (2) individual differences in the Dark Triad traits. Turkish participants (and men) were higher in Dark Triad traits than Australian participants (and women) were, and these differences were mediated by perceptions of a competitive world. All of the Dark Triad traits were correlated with a competitive but not a dangerous worldview. Country-level differences in the Dark Triad traits were mediated by competitive worldviews but not dangerous worldviews, and those effects were approximately the same in each sex although over twice as strong in men than in women. This study provided the first cross-cultural assessment of individual differences in the Dark Triad traits using a life history framework.

* * * 
The role of body posture on perceptions of attractiveness and self-esteem

Eva Tzschaschel (Macquarie University)
Ian Stephen (Macquarie University)

Attractiveness is hypothesised as a mechanism for identifying healthy, fertile mates, with cues from faces and bodies to physiological and psychological health. Little is known about the impact of body posture on attractiveness. Participants (N=108) were photographed twice in profile in their natural and corrected posture, and completed a validated self-esteem questionnaire. In Study 1, a correlational design, 38 observers rated the attractiveness of the photographs in natural posture as more attractive and higher self-esteem. In Study 2, an experimental design, 41 observers completed a forced-choice task, choosing upright posture as more attractive and higher self-esteem. However, people who have higher self-esteem do not stand more upright. Therefore, posture is probably not a valid cue to self-esteem. Possible explanations for the perception of upright posture as attractive and high in self-esteem are discussed.

* * *