Evidence for adaptive design in human gaze preference

Turning Heads: The Effects of Face View and Eye Gaze Direction on the Perceived Attractiveness of Expressive Faces

We investigated whether the perceived attractiveness of expressive faces was influenced by head turn and eye gaze towards or away from the observer. In all experiments, happy faces were consistently rated as more attractive than angry faces. A head turn towards the observer, whereby a full-face view was shown, was associated with relatively higher attractiveness ratings when gaze direction was aligned with face view (Experiment 1). However, preference for full-face views of happy faces was not affected by gaze shifts towards or away from the observer (Experiment 2a). In Experiment 3, the relative duration of each face view (front-facing or averted at 15°) during a head turn away or towards the observer was manipulated. There was benefit on attractiveness ratings for happy faces shown for a longer duration from the front view, regardless of the direction of head turn. Our findings support previous studies indicating a preference for positive expressions on attractiveness judgements, which is further enhanced by the front views of faces, whether presented during a head turn or shown statically. In sum, our findings imply a complex interaction between cues of social attention, indicated by the view of the face shown, and reward on attractiveness judgements of unfamiliar faces.

Sex differences in social cognition: The case of face processing

Several studies have demonstrated that women show a greater interest for social information and empathic attitude than men. This article reviews studies on sex differences in the brain, with particular reference to how males and females process faces and facial expressions, social interactions, pain of others, infant faces, faces in things (pareidolia phenomenon), opposite-sex faces, humans vs. landscapes, incongruent behavior, motor actions, biological motion, erotic pictures, and emotional information. Sex differences in oxytocin-based attachment response and emotional memory are also mentioned. In addition, we investigated how 400 different human faces were evaluated for arousal and valence dimensions by a group of healthy male and female University students. Stimuli were carefully balanced for sensory and perceptual characteristics, age, facial expression, and sex. As a whole, women judged all human faces as more positive and more arousing than men. Furthermore, they showed a preference for the faces of children and the elderly in the arousal evaluation. Regardless of face aesthetics, age, or facial expression, women rated human faces higher than men. The preference for opposite- vs. same-sex faces strongly interacted with facial age. Overall, both women and men exhibited differences in facial processing that could be interpreted in the light of evolutionary psychobiology. © 2016 Wiley Periodicals, Inc.

Effects of Head Nodding and Shaking Motions on Perceptions of Likeability and Approachability

It has been demonstrated that bowing motion of computer-generated female three-dimensional figures enhanced perceived attractiveness. Given that nodding and shaking head motions are used as communicative signals, such as signals of approval (and denial), these motions could be expected to modulate perceived trait impressions of model faces. We used movie clips of the nodding and shaking head motions of computer-generated figures and examined the modulation effects of these motions on perceived trait impressions (i.e., attractiveness, likability, and approachability). The results showed that the nodding head motion significantly increased ratings of subjective likability and approachability relative to those of the shaking or control conditions, whereas the shaking motion did not influence the ratings. Furthermore, it was shown that a nodding head motion of the computer-generated models primarily increased likability attributable to personality traits, rather than to physical appearance. We concluded that head nodding motion is treated as information regarding approach-related motivations and enhances perceived likeability.

Combined Effects of Gaze and Orientation of Faces on Person Judgments in Social Situations

In social situations, faces of others can vary simultaneously in gaze and orientation. How these variations affect different kinds of social judgments, such as attractiveness or trustworthiness, is only partly understood. Therefore, we studied how different gaze directions, head angles, but also levels of facial attractiveness affect perceived attractiveness and trustworthiness. We always presented pairs of faces - either two average attractive faces or a highly attractive together with a less attractive face. We also varied gaze and head angles showing faces in three different orientations, front, three-quarter and profile view. In Experiment 1 (N = 62), participants rated averted gaze in three-quarter views as more attractive than in front and profile views, and evaluated faces with direct gaze in front views as most trustworthy. Moreover, faces that were being looked at by another face were seen as more attractive. Independent of the head orientation or gaze direction, highly attractive faces were rated as more attractive and more trustworthy. In Experiment 2 (N = 54), we found that the three-quarter advantage vanished when the second face was blurred during judgments, which demonstrates the importance of the presence of another person-as in a triadic social situation-as well as the importance of their visible gaze. The findings emphasize that social evaluations such as trustworthiness are unaffected by the esthetic advantage of three-quarter views of two average attractive faces, and that the effect of a faces' attractiveness is more powerful than the more subtle effects of gaze and orientations.

Women prefer men who use metaphorical language when paying compliments in a romantic context

Language plays an important role in romantic attachment. However, it is unclear whether the structure and topic of language use might influence potential mate choice. We investigated 124 female students' preference for compliments paid by males incorporating either literal or metaphoric (conventional/novel) language and targeting their appearance or possessions (house) throughout their menstrual cycle. Male faces paired with novel metaphorical compliments were rated as more attractive by women than those paired with literal ones. Compliments targeting appearance increased male attractiveness more than possessions. Interestingly, compliments on appearance using novel metaphors were preferred by women in a relationship during the fertile phase but by single women during the luteal phase. A similar pattern of altered face attraction ratings was subsequently shown by subjects in the absence of the verbal compliments and even though they were unable to recognize the faces. Thus the maintained attraction bias for faces previously associated with figurative language compliments appears to be unconscious. Overall this study provides the first evidence that women find men who typically use novel metaphorical language to compliment appearance more attractive than those using prosaic language or complimenting possessions. The evolutionary significance for such a language use bias in mate selection is discussed.

Participant sexual orientation matters: new evidence on the gender bias in face recognition

Research participants' sexual orientation is not consistently taken into account in experimental psychological research. We argue that it should be in any research related to participant or target gender. Corroborating this argument, an example study is presented on the gender bias in face recognition, the finding that women correctly recognize more female than male faces. In contrast, findings with male participants have been inconclusive. An online experiment (N = 1,147) was carried out, on purpose over-sampling lesbian and gay participants. Findings demonstrate that the pro-female gender bias in face recognition is modified by male participants' sexual orientation. Heterosexual women and lesbians as well as heterosexual men showed a pro-female gender bias in face recognition, whereas gay men showed a pro-male gender bias, consistent with the explanation that differences in face expertise develop congruent with interests. These results contribute to the growing evidence that participant sexual orientation can be used to distinguish between alternative theoretical explanations of given gender-correlated patterns of findings.

Sex matters: Neural correlates of voice gender perception

The basis for different neural activations in response to male and female voices as well as the question, whether men and women perceive male and female voices differently, has not been thoroughly investigated. Therefore, the aim of the present study was to examine the behavioral and neural correlates of gender-related voice perception in healthy male and female volunteers. fMRI data were collected while 39 participants (19 female) were asked to indicate the gender of 240 voice stimuli. These stimuli included recordings of 3-syllable nouns as well as the same recordings pitch-shifted in 2, 4 and 6 semitone steps in the direction of the other gender. Data analysis revealed a) equal voice discrimination sensitivity in men and women but better performance in the categorization of opposite-sex stimuli at least in men, b) increased responses to increasing gender ambiguity in the mid cingulate cortex and bilateral inferior frontal gyri, and c) stronger activation in a fronto-temporal neural network in response to voices of the opposite sex. Our results indicate a gender specific processing for male and female voices on a behavioral and neuronal level. We suggest that our results reflect higher sensitivity probably due to the evolutionary relevance of voice perception in mate selection.

Intensity of smiling and attractiveness as facial signals of trustworthiness in women

Facial attractiveness is associated with a variety of positive social characteristics including trustworthiness. Variations in smiling, such as the appearance of the Duchenne marker and increased intensity of expression, have likewise been linked with positive judgments of trustworthiness. The study investigated the interaction of the effects of models' attractiveness and their smiling intensity on impressions of perceived trustworthiness. Participants rated the attractiveness and expressivity of neutral, low intensity, and high intensity smiling images of 45 women models. These images were also presented to a second group of participants who rated trustworthiness. Repeated measures analysis of covariance of the effects of attractiveness and manipulated smile intensity on trustworthiness indicated a main effect for smile intensity: increased smile intensity was associated with greater trustworthiness. Attractiveness also contributed to rated trustworthiness independently of smiling intensity. Results suggested there is an additional contribution of facial expression in creating social impressions of trustworthiness.

Social support influences preferences for feminine facial cues in potential social partners

Most previous studies of individual differences in women's and men's preferences for sexually dimorphic physical characteristics have focused on the importance of mating-related factors for judgments of opposite-sex individuals. Although studies have suggested that people may show stronger preferences for feminine individuals of both sexes under conditions where social support may be at a premium (e.g., during phases of the menstrual cycle where raised progesterone prepares women's bodies for pregnancy), these studies have not demonstrated that perceptions of available social support directly influence femininity preferences. Here we found that (1) women and men randomly allocated to low social support priming conditions demonstrated stronger preferences for feminine shape cues in own- and opposite-sex faces than did individuals randomly allocated to high social support priming conditions and (2) that people perceived men and women displaying feminine characteristics as more likely to provide them with high-quality social support than those displaying relatively masculine characteristics. Together, these findings suggest that social support influences face preferences directly, potentially implicating facultative responses whereby people increase their preferences for pro-social individuals under conditions of low social support.

Does alcohol consumption really affect asymmetry perception? A three-armed placebo-controlled experimental study

AIMS

  A possible explanation for increased levels of attractiveness of faces when under the influence of alcohol is the reduced ability to perceive bilateral asymmetry. This study tested the degree of preference by alcohol-dosed and non-alcohol-dosed participants for symmetrical faces and their ability to detect facial symmetry, while controlling for other explanations.

DESIGN

  Volunteers were recruited to a random allocation experiment with three conditions: alcoholic drink (alcohol dosed), non-alcoholic drink (placebo) and diluted orange cordial (control). Data on concentration, personality and demographics were collected. Dependent variables were symmetry preference and detection.

SETTING

  Laboratory, University of Roehampton.

PARTICIPANTS

  A total of 101 participants, mainly students (41 alcohol-dosed, 40 placebo, 20 control).

MEASUREMENTS

  Participants provided verbal responses to images of faces which were presented on a computer screen for 5 seconds each; the first task required a preference judgement and the second task consisted of a forced-choice response of whether or not a face was symmetrical. Levels of concentration, weight and level of alcohol dose were measured, and demographics plus additional psychological and health information were collected using a computer-based questionnaire.

FINDINGS

  In contrast to a previous investigation, there was no difference in symmetry preference between conditions (P = 0.846). In agreement with previous findings, participants who had not drunk alcohol were better at detecting whether a face was symmetrical or asymmetrical (P = 0.043). Measures of concentration did not differ between conditions (P = 0.214-0.438). Gender did not affect ability to detect symmetry in placebo or alcohol-dosed participants (P = 0.984, 0.499); however, alcohol-dosed females were shown to demonstrate greater symmetry preference than alcohol-dosed males (P = 0.004).

CONCLUSIONS

  People who are alcohol-dosed are subtly less able to perceive vertical, bilateral asymmetry in faces, with gender being a possible moderating factor.

Attention Capture by Direct Gaze is Robust to Context and Task Demands

Eye-tracking was used to investigate whether gaze direction would influence the visual scanning of faces, when presented in the context of a full character, in different social settings, and with different task demands. Participants viewed individual computer agents against either a blank background or a bar scene setting, during both a free-viewing task and an attractiveness rating task for each character. Faces with a direct gaze were viewed longer than faces with an averted gaze regardless of body context, social settings, and task demands. Additionally, participants evaluated characters with a direct gaze as more attractive than characters with an averted gaze. These results, obtained with pictures of computer agents rather than real people, suggest that direct gaze is a powerful attention grabbing stimulus that is robust to background context or task demands.

Reproductive ambition predicts partnered, but not unpartnered, women's preferences for masculine men

Changing circumstances alter the costs and benefits of choosing different mates and are thought to be reflected in women's mate preferences. Indeed, several lines of reasoning, and some prior studies, suggest that individual differences in women's preferences for cues of men's underlying health will be more apparent among partnered women than among unpartnered women. The current study shows that preferences for male faces with masculine shape cues, characteristics that are thought to signal men's underlying health, are positively correlated with partnered, but not unpartnered, women's reported reproductive ambition (i.e., their desire to become pregnant). These findings (1) present new evidence for systematic variation in women's mating strategies, (2) suggest that partnership status may be important for potentially adaptive variation in women's mate preferences, and (3) suggest that reproductive ambition may influence women's mate preferences. Alternative explanations for these findings, focusing on the possible effects of a range of variables that may be correlated with reproductive ambition in partnered women and influence their masculinity preferences, are also discussed.

Facial attractiveness: evolutionary based research

Face preferences affect a diverse range of critical social outcomes, from mate choices and decisions about platonic relationships to hiring decisions and decisions about social exchange. Firstly, we review the facial characteristics that influence attractiveness judgements of faces (e.g. symmetry, sexually dimorphic shape cues, averageness, skin colour/texture and cues to personality) and then review several important sources of individual differences in face preferences (e.g. hormone levels and fertility, own attractiveness and personality, visual experience, familiarity and imprinting, social learning). The research relating to these issues highlights flexible, sophisticated systems that support and promote adaptive responses to faces that appear to function to maximize the benefits of both our mate choices and more general decisions about other types of social partners.

Preliminary evidence that the limbal ring influences facial attractiveness

The limbal ring of the eye appears as a dark annulus where the iris meets the sclera. Both width and opacity of the limbal ring are influenced by iris pigmentation and optical properties of the region. With age the limbal ring becomes less prominent, making it a probabilistic indicator of youth and health. This raises the question: Are judgments of facial attractiveness sensitive to this signal in a potentially adaptive way? Here we show that the answer is yes. For male and female observers, both male and female faces with a dark and distinct limbal ring are rated as more attractive than otherwise identical faces with no limbal ring. This result is observed not just for upright faces but also for inverted faces, suggesting that the limbal ring is processed primarily as a local feature rather than as a configural feature in the analysis of facial beauty. We also discuss directions for future research that can clarify the role of the limbal ring in the visual perception of facial attractiveness.

Preliminary Evidence that the Limbal Ring Influences Facial Attractiveness

The limbal ring of the eye appears as a dark annulus where the iris meets the sclera. Both width and opacity of the limbal ring are influenced by iris pigmentation and optical properties of the region. With age the limbal ring becomes less prominent, making it a probabilistic indicator of youth and health. This raises the question: Are judgments of facial attractiveness sensitive to this signal in a potentially adaptive way? Here we show that the answer is yes. For male and female observers, both male and female faces with a dark and distinct limbal ring are rated as more attractive than otherwise identical faces with no limbal ring. This result is observed not just for upright faces but also for inverted faces, suggesting that the limbal ring is processed primarily as a local feature rather than as a configural feature in the analysis of facial beauty. We also discuss directions for future research that can clarify the role of the limbal ring in the visual perception of facial attractiveness.

Sad people avoid the eyes or happy people focus on the eyes? Mood induction affects facial feature discrimination

Depressed people tend to avoid eye-contact in social situations and in experimental settings, whereas happy people actively seek eye-contact. We report an experiment in which participants made discriminations between faces that had either configural or featural changes made to the eyes, nose, or head shape. The results showed participants induced to be happy detected changes in eyes more often than participants induced to be sad, but failed to detect changes in other facial features. Sad-induced participants detected changes to the head shape but not the eyes. The results are interpreted in terms of differential use of features attended to by happy and sad participants, whereby happy people are more likely to attend to eyes during face perception than sad people.

Neural markers of opposite-sex bias in face processing

Some behavioral and neuroimaging studies suggest that adults prefer to view attractive faces of the opposite sex more than attractive faces of the same sex. However, unlike the other-race face effect (Caldara et al., 2004), little is known regarding the existence of an opposite-/same-sex bias in face processing. In this study, the faces of 130 attractive male and female adults were foveally presented to 40 heterosexual university students (20 men and 20 women) who were engaged in a secondary perceptual task (landscape detection). The automatic processing of face gender was investigated by recording ERPs from 128 scalp sites. Neural markers of opposite- vs. same-sex bias in face processing included larger and earlier centro-parietal N400s in response to faces of the opposite sex and a larger late positivity (LP) to same-sex faces. Analysis of intra-cortical neural generators (swLORETA) showed that facial processing-related (FG, BA37, BA20/21) and emotion-related brain areas (the right parahippocampal gyrus, BA35; uncus, BA36/38; and the cingulate gyrus, BA24) had higher activations in response to opposite- than same-sex faces. The results of this analysis, along with data obtained from ERP recordings, support the hypothesis that both genders process opposite-sex faces differently than same-sex faces. The data also suggest a hemispheric asymmetry in the processing of opposite-/same-sex faces, with the right hemisphere involved in processing same-sex faces and the left hemisphere involved in processing faces of the opposite sex. The data support previous literature suggesting a right lateralization for the representation of self-image and body awareness.

Integrating gaze direction and sexual dimorphism of face shape when perceiving the dominance of others

Although gaze direction and face shape have each been shown to affect perceptions of the dominance of others, the question whether gaze direction and face shape have independent main effects on perceptions of dominance, and whether these effects interact, has not yet been studied. To investigate this issue, we compared dominance ratings of faces with masculinised shapes and direct gaze, masculinised shapes and averted gaze, feminised shapes and direct gaze, and feminised shapes and averted gaze. While faces with direct gaze were generally rated as more dominant than those with averted gaze, this effect of gaze direction was greater when judging faces with masculinised shapes than when judging faces with feminised shapes. Additionally, faces with masculinised shapes were rated as more dominant than those with feminised shapes when faces were presented with direct gaze, but not when faces were presented with averted gaze. Collectively, these findings reveal an interaction between the effects of gaze direction and sexually dimorphic facial cues on judgments of the dominance of others, presenting novel evidence for the existence of complex integrative processes that underpin social perception of faces. Integrating information from face shape and gaze cues may increase the efficiency with which we perceive the dominance of others.

Interactions among the Effects of Head Orientation, Emotional Expression, and Physical Attractiveness on Face Preferences

Previous studies have shown that preferences for direct versus averted gaze are modulated by emotional expressions and physical attractiveness. For example, preferences for direct gaze are stronger when judging happy or physically attractive faces than when judging disgusted or physically unattractive faces. Here we show that preferences for front versus three-quarter views of faces, in which gaze direction was always congruent with head orientation, are also modulated by emotional expressions and physical attractiveness; participants demonstrated preferences for front views of faces over three-quarter views of faces when judging the attractiveness of happy, physically attractive individuals, but not when judging the attractiveness of relatively unattractive individuals or those with disgusted expressions. Moreover, further analyses indicated that these interactions did not simply reflect differential perceptions of the intensity of the emotional expressions shown in each condition. Collectively, these findings present novel evidence that the effect of the direction of the attention of others on attractiveness judgments is modulated by cues to the physical attractiveness and emotional state of the depicted individual, potentially reflecting psychological adaptations for efficient allocation of social effort. These data also present the first behavioural evidence that the effect of the direction of the attention of others on attractiveness judgments reflects viewer-referenced, rather than face-referenced, coding and/or processing of gaze direction.

Sexual dimorphism of male face shape, partnership status and the temporal context of relationship sought modulate women's preferences for direct gaze

Most previous studies of face preferences have investigated the physical cues that influence face preferences. Far fewer studies have investigated the effects of cues to the direction of others' social interest (i.e. gaze direction) on face preferences. Here we found that unpartnered women demonstrated stronger preferences for direct gaze (indicating social interest) from feminine male faces than from masculine male faces when judging men's attractiveness for long-term relationships, but not when judging men's attractiveness for short-term relationships. Moreover, unpartnered women's preferences for direct gaze from feminine men were stronger for long-term than short-term relationships, but there was no comparable effect for judgements of masculine men. No such effects were evident among women with romantic partners, potentially reflecting different motivations underlying partnered and unpartnered women's judgements of men's attractiveness. Collectively these findings (1) complement previous findings whereby women demonstrated stronger preferences for feminine men as long-term than short-term partners, (2) demonstrate context-sensitivity in the integration of physical and social cues in face preferences, and (3) suggest that gaze preferences may function, at least in part, to facilitate efficient allocation of mating effort.