Ian D Stephen

• BSc, MPhil, PhD
• Professor (Associate) at Macquarie University

People lead increasingly sedentary lifestyles and spend extended periods sitting in slouched and head-forward positions, which can lead to health issues. People are so accustomed to seeing slouched posture that they may perceive it as normal and fail to notice their own slouched posture. We aim to investigate this possibility using the visual adapt...

Intuition often guides our thinking effectively, but it can also lead to consequential reasoning errors, underpinning poor decisions and biased judgments. Little is known about how people globally self-correct such intuitive reasoning errors and what enhances their correction. Defying prevailing models of reasoning, recent research suggests that pe...

Intuition often guides our thinking effectively, but it can also lead to consequential reasoning errors, underpinning poor decisions and biased judgments. Little is known about how people globally self-correct such intuitive reasoning errors and what enhances their correction. Defying prevailing models of reasoning, recent research suggests that pe...

Body image disturbance is a both a risk factor for, and a symptom of, many eating disorders and refers to the misperception of and dissatisfaction with one's own body. Women with high body dissatisfaction have been shown to direct more attention to low body mass index (BMI) bodies, which results in the overestimation of body size via body size adap...

Body image disturbance is a both a risk factor for, and a symptom of, many eating disorders and refers to the misperception of and dissatisfaction with one’s own body. Women with high body dissatisfaction have been shown to direct more attention to low body mass index (BMI) bodies, which results in the overestimation of body size via body size adap...

Body dissatisfaction—the negative subjective evaluation of one’s body—is associated with negative health outcomes, including eating disorders such as anorexia nervosa. Eye-tracking studies consistently show that women with high body dissatisfaction, compared to women with low body dissatisfaction, direct more gaze toward low weight bodies. However,...

Studies suggest that an attentional bias to thin bodies is common among those with high levels of body dissatisfaction, which is a risk factor for, and symptom of, various eating disorders. However, these studies have predominantly been conducted in Western countries with body stimuli involving images of White people. In a preregistered study, we r...

The dominant evolutionary theory of sexual attraction posits that attraction serves as a psychobehavioral and motivational mechanism for identifying healthy, fertile, and appropriate mates. According to this theory, humans and animals display cues that reflect their mate quality and, if successful, are perceived as attractive by potential mates. Th...

Previous cross‐cultural eye‐tracking studies examining face recognition discovered differences in the eye movement strategies that observers employ when perceiving faces. However, it is unclear (1) the degree to which this effect is fundamentally related to culture and (2) to what extent facial physiognomy can account for the differences in looking...

First impressions of a person, including social judgements, are often based on appearance. The widely accepted valence-dominance model of face perception (Oosterhof and Todorov 2008 Proc. Natl Acad. Sci. USA 105 , 11 087–11 092 ( doi:10.1073/pnas.0805664105 )) posits that social judgements of faces fall along two orthogonal dimensions: trustworthin...

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about...

Estimating the size of bodies is crucial for interactions with physical and social environments. Body‐size perception is malleable and can be altered using visual adaptation paradigms. However, it is unclear whether such visual adaptation effects also transfer to other modalities and influence, for example, the perception of tactile distances. In t...

It is widely accepted that holistic processing is important for face perception. However, it remains unclear whether the other-race effect (ORE) (i.e. superior recognition for own-race faces) arises from reduced holistic processing of other-race faces. To address this issue, we adopted a cross-cultural design where Malaysian Chinese, African, Europ...

The dominant evolutionary theory of sexual attraction posits that attraction serves as a psychological mechanism for identifying healthy, fertile, and appropriate mates. According to this theory, humans and animals display cues that reflect their mate quality and are perceived as attractive by potential mates. There is evidence for such valid cues...

Existing work suggests that observers' perceptions of sociosexuality from strangers' faces are positively associated with individuals' self-reported sociosexuality. However it is not clear what cues observers use to form these judgements. Over two studies we examined whether sociosexuality is reflected in faces, which cues contain information about...

Over the past 10 years, Oosterhof and Todorov’s valence–dominance model has emerged as the most prominent account of how people evaluate faces on social dimensions. In this model, two dimensions (valence and dominance) underpin social judgements of faces. Because this model has primarily been developed and tested in Western regions, it is unclear w...

Individual faces are rated as more attractive when presented in a group compared to when presented individually; a finding dubbed the ‘cheerleader effect’. As a relatively recent discovery, the conditions necessary to observe the effect are not clearly understood. We sought to better define these conditions by examining two parameters associated wi...

Estimating the size of bodies is crucial for interactions with physical and social environments. Body size perception is malleable and can be altered using visual adaptation paradigms. However, it is unclear whether such visual adaptation effects also transfer to other modalities and influence, for example, the perception of tactile distances. In t...

Our perceptual sensitivity to cues of socially and sexually relevant physiological and psychological traits in others is remarkable. For such sensitivity to evolve, the directly perceptible qualities of others (which include intrinsic physical traits, such as height, weight, body odor, facial morphology, and body shape; as well as behaviorally modi...

The own-race bias (ORB) is a reliable phenomenon across cultural and racial groups where unfamiliar faces from other races are usually remembered more poorly than own-race faces (Meissner and Brigham, 2001). By adopting a yes–no recognition paradigm, we found that ORB was pronounced across race groups (Malaysian–Malay, Malaysian–Chinese, Malaysian–...

The own-race bias (ORB) is a reliable phenomenon across cultural and racial groups where unfamiliar faces from other races are usually remembered more poorly than own-race faces (Meissner and Brigham, 2001). By adopting a yes–no recognition paradigm, we found that ORB was pronounced across race groups (Malaysian–Malay, Malaysian–Chinese, Malaysian–...

Body image disturbance – a cause of distress amongst the general population and those diagnosed with various disorders – is often attributed to the media’s unrealistic depiction of ideal bodies. These ideals are strongly gendered, leading to pronounced fat concern amongst females, and a male preoccupation with muscularity. Recent research suggests...

Visual adaptation has been proposed as a mechanism linking viewing images of thin women’s bodies with body size and shape misperception (BSSM). Non-Caucasian populations appear less susceptible to BSSM, possibly because adaptation to thin Caucasian bodies in Western media may not fully transfer to own-race bodies. Experiment 1 used a cross-adaptati...

Many individuals experience body-size and -shape misperception (BSSM). Body-size overestimation is associated with body dissatisfaction, anxiety, depression, and the development of eating disorders in individuals who desire to be thinner. Similar symptoms have been noted for those who underestimate their muscularity. Conversely, individuals with hi...

Over the last ten years, Oosterhof and Todorov’s valence-dominance model has emerged as the most prominent account of how people evaluate faces on social dimensions. In this model, two dimensions (valence and dominance) underpin social judgments of faces. Because this model has primarily been developed and tested in Western regions, it is unclear w...

Prolonged exposure to wide (thin) bodies causes a perceptual aftereffect such that subsequently viewed bodies appear thinner (wider) than they actually are. This phenomenon is known as visual adaptation. We used the adaptation paradigm to examine the gender selectivity of the neural mechanisms encoding body size and shape. Observers adjusted female...

Prolonged exposure to wide (thin) bodies causes a perceptual aftereffect such that subsequently-viewed bodies appear thinner (wider) than they actually are. This phenomenon is known as visual adaptation. We used the adaptation paradigm to examine the gender selectivity of the neural mechanisms encoding body size and shape. Observers adjusted female...

Body image disturbance – a cause of distress amongst the general population and those diagnosed with various disorders – is often attributed to the media’s unrealistic depiction of ideal bodies. These ideals are strongly gendered, leading to pronounced fat concern amongst females, and a male preoccupation with muscularity. Recent research suggests...

Visual adaptation has been proposed as a mechanism linking viewing images of thin women’s bodies with body size and shape misperception (BSSM). Non-Caucasian populations appear less susceptible to BSSM, possibly because adaptation to thin Caucasian bodies in Western media may not fully transfer to own-race bodies. Experiment 1 used a cross-adaptati...

Human behaviour is not only influenced by the physical presence of others, but also implied social presence. This study examines the impact of awareness of being eye-tracked on eye movement behaviour in a laboratory setting. During a classic yes/no face recognition task, participants were made to believe that their eye movements were recorded (or n...

Facial skin color influences the perceived health and attractiveness of Caucasian faces, and has been proposed as a valid cue to aspects of physiological health. Similar preferences for skin color have previously been found in African participants, while different preferences have been found among mainland Chinese participants. Here, we asked Malay...

In one of the founding texts of the field of ethology, On Aims and Methods of Ethology, Niko Tinbergen (1963) proposed that a complete understanding of any given behavior necessitates explanation at four different levels (the “four major problems of biology”): causal (or mechanistic), ontogenetic, phylogenetic, and functional. These levels of expla...

Much research on moral judgment is centered on moral dilemmas in which deontological perspectives (i.e., emphasizing rules, individual rights and duties) are in conflict with utilitarian judgements (i.e., following the greater good defined through consequences). A central finding of this field Greene et al. showed that psychological and situational...

Despite evidence indicating body odor (BO) preference is an important driver in mate selection, previous studies have only investigated females' preferences for the BO of strangers. Therefore, the aim of the current study was to determine if partnered females prefer their partner's BO compared to that of others males' BO. Forty partnered and 42 sin...

Objective Prolonged exposure to large/small bodies causes aftereffects in perceived body size. Outside the laboratory, individuals repeatedly exposed to small (large) bodies tend to over‐ (under‐) estimate their size and exhibit increased (decreased) body dissatisfaction. Why, among individuals exposed to approximately equivalent distributions of b...

Prolonged visual exposure, or ‘adaptation’, to thin (wide) bodies causes a perceptual aftereffect such that subsequently seen bodies appear wider (thinner) than they actually are. Here, we conducted two experiments investigating the effect of rotating the orientation of the test stimuli by 90° from that of the adaptor. Aftereffects were maximal whe...

Marriages between White men and Asian women are over twice as frequent as those between White women and Asian men. Recent research has proposed that this imbalance may be explained by the finding that, on average, White men are perceived as more attractive than Asian men, and Asian women are perceived as more attractive than White women, possibly b...

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...

Body size misperception–the belief that one is larger or smaller than reality–affects a large and growing segment of the population. Recently, studies have shown that exposure to extreme body stimuli results in a shift in the point of subjective normality, suggesting that visual adaptation may be a mechanism by which body size misperception occurs....

Coefficients of the reversed mediation model. Ϯ p < .10 * p < .05 ** p < .01, *** p < .001, # Bootstrapped 95% confidence intervals do not cross 0. See S2 Fig for model design. (DOCX)

Design of the supplementary mediation model. (DOCX)

Design of the reversed mediation model. (DOCX)

Coefficients of the supplementary mediation model. Ϯ p < .10 * p < .05 ** p < .01, *** p < .001, # Bootstrapped 95% confidence intervals do not cross 0. See S1 Fig for model design. (DOCX)

Although body size and shape misperception (BSSM) is a common feature of anorexia nervosa, bulimia nervosa and muscle dysmorphia, little is known about its underlying neural mechanisms. Recently, a new approach has emerged, based on the long-established non-invasive technique of perceptual adaptation, which allows for inferences about the structure...

Facial cues contribute to attractiveness, including shape cues such as symmetry, averageness, and sexual dimorphism. These cues may represent cues to objective aspects of physiological health, thereby conferring an evolutionary advantage to individuals who find them attractive. The link between facial cues and aspects of physiological health is the...

Objectives: Following predictions from life history theory, we sought to identify acute trade-offs between reproductive effort (as measured by psychological arousal) and somatic maintenance (via functional measures of innate immunity) during conditions of severe energetic imbalance. Methods: Sixty-six male ultramarathon runners (ages 20 to 37 ye...

Objectives: Following predictions from life history theory, we sought to identify acute trade-offs between reproductive effort (as measured by psychological arousal) and somatic maintenance (via functional measures of innate immunity) during conditions of severe energetic imbalance. Methods: Sixty-six male ultramarathon runners (ages 20 to 37 years...

We argue that the CLASH model makes a number of questionable assumptions about the harshness and unpredictability of low-latitude environments, calling into question the life history strategy approach used, and that it is inconsistent with more nuanced global patterns of violence. We suggest an alternative account for less violence at high latitude...

Skin carotenoid coloration has been proposed as a valid cue to health in humans, reflecting fruit and vegetable intake, and enhancing apparent health. Supplementation with a carotenoid-rich fruit and vegetable smoothie affects skin color, but it is not known if this skin color change enhances healthy appearance. In three experiments, we examine the...

Although research addressing body size misperception has focused on socio-cognitive processes, such as internalization of the “ideal” images of bodies in the media, the perceptual basis of this phenomenon remains largely unknown. Further, most studies focus on body size per se even though this depends on both fat and muscle mass – variables that ha...

We adopt Tinbergen's (1963) “four questions” approach to strengthen the criticism by Maestripieri et al. of the non-evolutionary accounts of favouritism toward attractive individuals, by showing which levels of explanation are lacking in these accounts. We also use this approach to propose ways in which the evolutionary account may be extended and...

Prolonged exposure to images of narrow bodies has been shown to induce a perceptual aftereffect, such that observers’ point of subjective normality (PSN) for bodies shifts toward narrower bodies. The converse effect is shown for adaptation to wide bodies. In low-level stimuli, object attention (attention directed to the object) and spatial attentio...

Human axillary sweat may provide information pertaining to genetic relatedness and health status. A significant contributor to good health, both in the short and longer term, is a diet rich in fruit and vegetables. In this study we tested whether dietary fruit and vegetable intake, assessed indirectly by skin spectrophotometry (assessing dietary ca...

Body size misperception is common amongst the general public and is a core component of eating disorders and related conditions. While perennial media exposure to the “thin ideal” has been blamed for this misperception, relatively little research has examined visual adaptation as a potential mechanism. We examined the extent to which the bodies of...

The dominant evolutionary theory of physical attraction posits that attractiveness reflects physiological health, and attraction is a mechanism for identifying a healthy mate. Previous studies have found that perceptions of the healthiest body mass index (weight scaled for height; BMI) for women are close to healthy BMI guidelines, while the most a...

High performance level in face recognition studies does not seem to be replicable in real-life situations possibly because of the artificial nature of laboratory studies. Recognizing faces in natural social situations may be a more challenging task, as it involves constant examination of dynamic facial motions that may alter facial structure vital...

We perceive color everywhere and on everything that we encounter in daily life. Color science has progressed to the point where a great deal is known about the mechanics, evolution, and development of color vision, but less is known about the relation between color vision and psychology. However, color psychology is now a burgeoning, exciting area...

Studies have shown that while East Asians focused on the center of the face to recognize identities, participants adapted their strategy by focusing more on the eyes to identify emotions, suggesting that the eyes may contain salient information pertaining to emotional state in Eastern cultures. However, Western Caucasians employ the same strategy b...

Consumption of dietary carotenoids or carotenoid supplements can alter the color (yellowness) of human skin through increased carotenoid deposition in the skin. As fruit and vegetables are the main dietary sources of carotenoids, skin yellowness may be a function of regular fruit and vegetable consumption. However, most previous studies have used t...

Alcohol consumption is known to be associated with risky sexual behaviours, but this relationship may be complex and bidirectional. We explored whether alcohol consumption leads to the consumer being rated as more attractive than sober individuals. Heterosexual social alcohol consumers completed an attractiveness-rating task, in which they were pre...

Previous work showed high agreement in facial attractiveness preferences within and across cultures. The aims of the current study were twofold. First, we tested cross-cultural agreement in the attractiveness judgements of White Scottish and Black South African students for own- and other-ethnicity faces. Results showed significant agreement betwee...

Recent research has shown facial adiposity (apparent weight in the face) to be a significant predictor of both attractiveness and health, thus making it an important determinant of mate selection. Studies looking at the relationship between attractiveness and health have shown that individuals differentiate between the two by preferring a lower wei...

Perceived weight in the face and body size have been shown to be significant predictors of both attractiveness and health. Studies looking at the relationship between attractiveness, perceived health, and perceived weight in faces have found that individuals prefer a lower weight for attractiveness than for apparent health. Here, a group of twenty-...

Tinbergen’s influential paper, On Aims and Methods of Ethology , has had a lasting impact on facial attractiveness research. While researchers rarely explicitly acknowledge the influence of Tinbergen’s ideas, the field has embraced evolutionary thinking in recent years. This focus on functional and phylogenetic explanations has led to the generatio...

Human facial skin colour reflects individuals' underlying health (Stephen et al 2011 Evolution & Human Behavior 32 216-227); and enhanced facial skin CIELab b* (yellowness), a* (redness), and L* (lightness) are perceived as healthy (also Stephen et al 2009a International Journal of Primatology 30 845-857). Here, we examine Malaysian Chinese partici...

A substantial number of studies indicate that human facial features such as symmetry and averageness are preferred in human mate choice. Little is known, however, about face preferences in intrapopulation or between-cultural settings as only a few studies have addressed this topic. One hypothesis is that people prefer faces that resemble faces from...

Pathogen-relevant variables (e.g., regional variation in pathogen prevalence, individual differences in sensitivity to pathogen disgust) have been found to be associated with judgments and preferences surrounding physical attractiveness, in line with the view that certain morphological features and configurations indicate health and/or immunocompet...

We agree that fruit and vegetable consumption is likely to confer health benefits by substituting refined carbohydrates, saturated fats, and other foodstuffs that are unambiguously deleterious to health. We argue, though, that fruit and vegetables convey additional active benefits to human health. While it is true that trials have consistently indi...

Much attractiveness research has focused on face shape. The role of masculinity (which for adults is thought to be a relatively stable shape cue to developmental testosterone levels) in male facial attractiveness has been examined, with mixed results. Recent work on the perception of skin color (a more variable cue to current health status) indicat...

In a range of non-human primate, bird and fish species, the intensity of red coloration in males is associated with social dominance, testosterone levels and mate selection. In humans too, skin redness is associated with health, but it is not known whether - as in non-human species - it is also associated with dominance and links to attractiveness...

Fruit and vegetable consumption is inadequate among adults in the United States; this contributes to preventable morbidity and mortality. More effective dietary intervention strategies are needed. Recently, interventions that advertise the consequences of behavior for appearance have been successful in modifying sun-exposure habits and tobacco use....

East Asian and white Western observers employ different eye movement strategies for a variety of visual processing tasks, including face processing. Recent eye tracking studies on face recognition found that East Asians tend to integrate information holistically by focusing on the nose while white Westerners perceive faces featurally by moving betw...

Recent research demonstrates a marked influence of skin colour on facial appearance: enhanced skin redness and yellowness increases perceived healthiness and attractiveness. We have investigated the basis of skin colour associations with health, and examined the perceptual sensitivity to change in skin colour. Reduced blood oxygenation and skin per...

The links between appearance and health influence human social interactions and are medically important, yet the facial cues influencing health judgments are unclear, and few studies describe connections to actual health. Increased facial skin yellowness (CIELab b*) and lightness (L*) appear healthy in Caucasian faces, but it is unclear why. Skin y...

The 129 facial landmarks used in the morphometric analyses of masculinity. Landmarks are represented on a composite female face. For definitions of landmarks see Stephan et al (2005). (0.65 MB TIF)

Distribution of discriminant function scores for males and females, sample 2. Stacked histogram showing distribution of discriminant function scores for males (n = 75) and female (n = 75) from sample 2. Faces with discriminant scores >0 were classified as male by the function, those with scores <0 were classified as female. (1.01 MB TIF)

Examples of skin patches from sample 2. a) Patches scoring low (left) and high (right) for lightness (L*) b) Patches scoring low (left) and high (right) for redness (a*) c) Patches scoring low (left) and high (right) for yellowness (b*) (0.45 MB TIF)

Principal components for the morphometric analysis of Sample 1. (0.04 MB DOC)