Facial Structure Is a Reliable Cue of Aggressive Behavior

ABSTRACT— Facial width-to-height ratio is a sexually dimorphic metric that is independent of body size and may have been shaped by sexual selection. We recently showed that this metric is correlated with behavioral aggression in men. In Study 1, observers estimated the propensity for aggression of men photographed displaying neutral facial expressions and for whom a behavioral measure of aggression was obtained. The estimates were correlated strongly with the facial width-to-height ratio of the stimulus faces and with the actual aggression of the men. These results were replicated in Study 2, in which the exposure to each stimulus face was shortened to 39 ms. Participants' estimates of aggression for each stimulus face were highly correlated between Study 2 (39-ms exposure) and Study 1 (2,000-ms exposure). These findings suggest that the facial width-to-height ratio may be a cue used to predict propensity for aggression in others.     

Cross-ethnic assessment of body weight and height on the basis of faces

Previous research has revealed a strong relationship between mere visual facial cues and body weight. They can be exploited to validly judge the weight of the human body. We tested to what extent observers are able to judge body weight and height on the basis of same-ethnicity and different-ethnicity faces. Caucasian and Asian observers saw Caucasian and Asian faces and estimated the person’s weight and height – merely on the basis of greyscale photographs of the face. These height and weight estimates were influenced by ethnocentric specifics of familiar face proportion and face–body relationship. Own-ethnicity weight estimations showed higher accuracy than foreign-ethnicity estimations. Observers ignored the changed base-rate for weight of other-culture faces in a culture-egocentric fashion. Height judgments, in contrast, reflect a higher degree of sophistication. A bias toward the own, familiar body proportion was visible here, especially for Japanese observers—however, the height judgments showed that observers were able to incorporate the other-ethnicity height proportion to some extent.     

Attentional bias for words and faces in social anxiety

Conflicting findings concerning the nature and presence of attentional bias in social anxiety and social phobia have been reported in the literature. This paper reports the findings of two studies comparing people with high and low social anxiety on dot probe tasks using words, faces photographed in front view, and faces photographed in profile as stimuli. In Study 1 those with high social anxiety displayed an attentional bias towards negative faces. The low social anxiety group showed an attentional bias towards positive faces. No significant effects were observed on the dot probe using words as stimuli. Study 2 used pairs of faces presented in profile as though looking at each other. One of the faces displayed either a positive, negative or neutral expression. The second face always had a neutral expression, and in half of the trials it was the subject's own face. The findings of this more ecologically valid procedure replicated those of Study 1. Facilitated attention to dots following emotional faces was specific to threatening facial stimuli. From these studies it appears that the facial dot probe task is a more sensitive index of attentional bias than the word task in a non-clinical sample with social anxiety.     

How accurately do young children and adults discriminate the gender of natural faces?

The effects of gender-relevant facial features and hairstyles on discrimination of sex of photographed men and women were examined. The stimuli were 36 photographs of natural faces: 9 masculine-males, 9 feminine-males, 9 masculine-females, and 9 feminine-females. Each of the nine faces had one of three hairstyles, hair concealed, short hair, or long hair. 33 children (M age=5:10) and 28 adults were asked to identify the sex of each stimulus. Children had difficulties with cross-gender faces and cross-gender hairstyles, such as a feminine-male face with long hair. Adults' discriminations were accurate except for masculine-female faces, while children's decisions depended both on hairstyle and internal facial features. Children's discriminations might be based both on their perceptual skill in detecting critical visual features and their knowledge of men and women.     

Brain and face: communicating signals of health in the left and right sides of the face

In human communication and mate selection the appearance of health sends signals regarding biological fitness. We compared the appearance of health in the sides of the face to previous results on left-right facial asymmetry in the appearance of beauty (1). The stimuli were created by aligning the left and right sides of the face each with its own mirror image. Here, participants viewed 38 pairs of left-left and right-right faces and judged which member of the pair looked healthier. No significant interaction emerged between decision (health vs attractiveness) and face side. Rather, in women's faces right-right was significantly more healthy and attractive than left-left, while in men's faces there was no significant left-right difference. In biology and evolution, health and beauty are closely linked and the findings here confirm this relationship in human faces.     

Facial emotion recognition during pregnancy: Examining the effects of facial age and affect

It is vital that new mothers quickly and accurately recognize their child’s facial expressions. There is evidence that during pregnancy women develop enhanced processing of facial features associated with infancy and distress, as these cues signal vulnerability and are therefore biologically salient. In this study, 51 pregnant women at 17–36 weeks gestation watched neutral infant and adult faces gradually morph into either happy or sad expressions. We measured the speed and accuracy with which participants were able to recognize facial affect (happy vs. sad) across facial ages (infant vs. adult). Participants were faster and more accurate at recognizing happy versus sad faces and adult versus infant faces. We discuss how prior exposure to a certain face type may explain faster recognition. We also consider these results in the context of evidence indicating positive affect is recognized more quickly, but associated with slower attention and detection.     

The Thatcher illusion in squirrel monkeys (Saimiri sciureus)

Like humans, Old World monkeys are known to use configural face processing to distinguish among individuals. The ability to recognize an individual through the perception of subtle differences in the configuration of facial features plays an important role in social cognition. To test this ability in New World monkeys, this study examined whether squirrel monkeys experience the Thatcher illusion, a measure of face processing ability in which changes in facial features are difficult to detect in an inverted face. In the experiment, the monkeys were required to distinguish between a target face and each of the three kinds of distracter faces whose features were altered to be different from those of the target. For each of the pairs of target and distracter faces, four rotation-based combinations of upright and inverted face presentations were used. The results revealed that when both faces were inverted and the eyes of the distracter face were altered by rotating them at an angle of 180° from those of the target face, the monkeys' discrimination learning was obstructed to a greater extent than it was under the other conditions. Thus, these results suggest that the squirrel monkey does experience the Thatcher illusion. Furthermore, it seems reasonable to assume that squirrel monkeys can utilize information about facial configurations in individual recognition and that this facial configuration information could be useful in their social communications.     

How do rhesus monkeys (<Emphasis Type="Italic">Macaca mulatta</Emphasis>) scan faces in a visual paired comparison task?

When novel and familiar faces are viewed simultaneously, humans and monkeys show a preference for looking at the novel face. The facial features attended to in familiar and novel faces, were determined by analyzing the visual exploration patterns, or scanpaths, of four monkeys performing a visual paired comparison task. In this task, the viewer was first familiarized with an image and then it was presented simultaneously with a novel and the familiar image. A looking preference for the novel image indicated that the viewer recognized the familiar image and hence differentiates between the familiar and the novel images. Scanpaths and relative looking preference were compared for four types of images: (1) familiar and novel objects, (2) familiar and novel monkey faces with neutral expressions, (3) familiar and novel inverted monkey faces, and (4) faces from the same monkey with different facial expressions. Looking time was significantly longer for the novel face, whether it was neutral, expressing an emotion, or inverted. Monkeys did not show a preference, or an aversion, for looking at aggressive or affiliative facial expressions. The analysis of scanpaths indicated that the eyes were the most explored facial feature in all faces. When faces expressed emotions such as a fear grimace, then monkeys scanned features of the face, which contributed to the uniqueness of the expression. Inverted facial images were scanned similarly to upright images. Precise measurement of eye movements during the visual paired comparison task, allowed a novel and more quantitative assessment of the perceptual processes involved the spontaneous visual exploration of faces and facial expressions. These studies indicate that non-human primates carry out the visual analysis of complex images such as faces in a characteristic and quantifiable manner.     

面孔吸引力的整体表征及其动态性增强

面孔作为一种高级的视觉刺激,在人际交往中有着无可替代的作用。其中,面孔吸引力更是影响着日常生活的重要社交决策,如择偶、交友、求职、社会交换等。长久以来,研究者们从面孔特征、社会信息和观察者因素等角度不断探索着人们对静态面孔吸引力的感知,且多从进化角度加以解释。但是,人们如何表征面孔吸引力以及其动态性增强机制仍未可知。本项目通过两个研究,分别从面孔吸引力的整体表征,以及面孔动态性通过影响整体加工、影响对整体信息和特征信息的注意、以及影响社会信息来增强吸引力,从这两个角度尝试回答这一问题。在研究1中,本项目从整体加工的角度探索了面孔吸引力的认知表征。研究1.1通过评分任务和适应范式探索高空间频率（更多局部特征）和低空间频率（更多整体特征）对面孔吸引力的影响,旨在从空间频率探讨面孔吸引力的整体表征。研究1.2通过操纵面孔对称性和面孔常态性探索面孔常态性在面孔对称性和面孔吸引力间的中介作用,探讨面孔吸引力的常态构型表征。研究1.3引入“三庭五眼”这一中国传统面孔审美理论,通过评分任务和适应范式研究“三庭五眼” 构型是否符合中国人对高吸引力中国面孔的表征,以此探讨面孔吸引力的整体表征。研究1.4通过评分任务和适应范式考察局部面孔遮挡是否促进整体面孔吸引力,以及这种促进作用是否由于人们通过局部特征“脑补”出了完整面孔。研究2从整体加工、注意和生命力的角度探讨面孔吸引力的动态性增强机制。研究2.1使用合成效应范式测量动态面孔吸引力的整体加工,探索动静态面孔的吸引力差异是否源于其整体加工程度的不同。研究2.2使用注意分散范式,并结合眼动技术,探讨人们对动静态面孔的注视模式是否存在差异,这种差异是否能解释动态面孔吸引力的增强。研究2.3结合问卷法、实验法和结构方程模型,考察了生命力这一社会因素对动静态面孔吸引力的影响。本项目探讨了面孔吸引力的认知表征以及其动态性增强机制,有助于我们进一步理解人们对面孔吸引力的认知加工以及人类欣赏美这一高级智能。同时,本项目的结果对于日常人际交往和面孔吸引力相关算法的优化等方面也有潜在的应用价值。     

The perception of attractiveness and trustworthiness in male faces affects hypothetical voting decisions differently in wartime and peacetime scenarios

Facial appearance of candidates has been linked to real election outcomes. Here we extend these findings by examining the contributions of attractiveness and trustworthiness in male faces to perceived votability. We first use real faces to show that attractiveness and trustworthiness are positively and independently related to perceptions of good leadership (rating study). We then show that computer graphic manipulations of attractiveness and trustworthiness influence choice of leader (Experiments 1 and 2). Finally, we show that changing context from wartime to peacetime can affect which face receives the most votes. Attractive faces were relatively more valued for wartime and trustworthy faces relatively more valued for peacetime (Experiments 1 and 2). This pattern suggests that attractiveness, which may indicate health and fitness, is perceived to be a useful attribute in wartime leaders, whereas trustworthiness, which may indicate prosocial traits, is perceived to be more important during peacetime. Our studies highlight the possible role of facial appearance in voting behaviour and the role of attributions of attractiveness and trust. We also show that there may be no general characteristics of faces that make them perceived as the best choice of leader; leaders may be chosen because of characteristics that are perceived as the best for leaders to possess in particular situations.     

The perception of attractiveness and trustworthiness in male faces affects hypothetical voting decisions differently in wartime and peacetime scenarios

Facial appearance of candidates has been linked to real election outcomes. Here we extend these findings by examining the contributions of attractiveness and trustworthiness in male faces to perceived votability. We first use real faces to show that attractiveness and trustworthiness are positively and independently related to perceptions of good leadership (rating study). We then show that computer graphic manipulations of attractiveness and trustworthiness influence choice of leader (Experiments 1 and 2). Finally, we show that changing context from wartime to peacetime can affect which face receives the most votes. Attractive faces were relatively more valued for wartime and trustworthy faces relatively more valued for peacetime (Experiments 1 and 2). This pattern suggests that attractiveness, which may indicate health and fitness, is perceived to be a useful attribute in wartime leaders, whereas trustworthiness, which may indicate prosocial traits, is perceived to be more important during peacetime. Our studies highlight the possible role of facial appearance in voting behaviour and the role of attributions of attractiveness and trust. We also show that there may be no general characteristics of faces that make them perceived as the best choice of leader; leaders may be chosen because of characteristics that are perceived as the best for leaders to possess in particular situations.     

Tolerance for distorted faces: Challenges to a configural processing account of familiar face recognition

Face recognition is widely held to rely on ‘configural processing’, an analysis of spatial relations between facial features. We present three experiments in which viewers were shown distorted faces, and asked to resize these to their correct shape. Based on configural theories appealing to metric distances between features, we reason that this should be an easier task for familiar than unfamiliar faces (whose subtle arrangements of features are unknown). In fact, participants were inaccurate at this task, making between 8% and 13% errors across experiments. Importantly, we observed no advantage for familiar faces: in one experiment participants were more accurate with unfamiliars, and in two experiments there was no difference. These findings were not due to general task difficulty – participants were able to resize blocks of colour to target shapes (squares) more accurately. We also found an advantage of familiarity for resizing other stimuli (brand logos). If configural processing does underlie face recognition, these results place constraints on the definition of ‘configural’. Alternatively, familiar face recognition might rely on more complex criteria – based on tolerance to within-person variation rather than highly specific measurement.     

Body weight, not facial width-to-height ratio, predicts aggression in pro hockey players

Studies indicate that facial characteristics may predict behavior, but it is unclear if this will hold within highly selective populations. One relevant characteristic is the face’s width-to-height ratio (FWHR), a sexually dimorphic trait that has been shown to predict aggression. That FWHR may predict aggression within highly selective populations was suggested by Carré and McCormick’s (2008) finding that professional hockey players with greater FWHRs accrued more penalties. We attempted to replicate this result using all NHL players. We also explored fighting penalties as another aggression measure and height and weight as additional aggression predictors. We found that body weight predicted substantial variance in aggression but FWHR did not. Thus, in highly selective populations, inferences based on faces may be inaccurate.     

Human facial discrimination in horses: can they tell us apart?

The human–horse relationship has a long evolutionary history. Horses continue to play a pivotal role in the lives of humans and it is common for humans to think their horses recognize them by face. If a horse can distinguish his/her human companion from other humans, then evolution has supplied the horse with a very adaptive cognitive ability. The current study used operant conditioning trials to examine whether horses could discriminate photographed human faces and transfer this facial recognition ability a novel setting. The results indicated the horses (a) learned to discriminate photographs of the unrelated individuals, fraternal twins, and identical twins and (b) demonstrated transfer of facial recognition by spending more time with their S+ woman in the field test.     

The tipping point of animacy. How, when, and where we perceive life in a face

Faces capture humans' attention; yet, beyond aesthetic appreciation, it is presumably not the face itself that interests people but the mind behind it. Minds think, feel, and act in ways that have direct consequences for well-being, but despite their importance, how minds are perceived in faces is not well understood. We investigated this mechanism by presenting participants with morphed images created from animate (human) and inanimate (mannequin) faces. Life and mind were perceived to "appear" at a consistent location on the morph continuum, close to the human endpoint. This location constituted a categorical boundary, as evidenced by increased sensitivity to differences in image pairs that straddled this tipping point. Additionally, the impression of life was gleaned from the eyes more than from other facial features. These results suggest that human beings are highly attuned to specific facial cues, carried largely in the eyes, that gate the categorical perception of life.     

7-11-year-old children show an advantage for matching and recognizing the internal features of familiar faces: Evidence against a developmental shift

Adults are better at recognizing familiar faces from the internal facial features (eyes, nose, mouth) than from the external facial features (hair, face outline). However, previous research suggests that this “internal advantage” does not appear until relatively late in childhood, and some studies suggest that children rely on external features to recognize all faces, whether familiar or not. We use a matching task to examine face processing in 7-8- and 10-11-year-old children. We use a design in which all face stimuli can be used as familiar items (for participants who are classmates) and unfamiliar items (for participants from a different school). Using this design, we find an internal feature advantage for matching familiar faces, for both groups of children. The same children were then shown the external and internal features of their classmates and were asked to name or otherwise identify them. Again, both age groups identified more of their classmates correctly from the internal than the external features. This is the first time an internal advantage has been reported in this age group. Results suggest that children as young as 7 process faces in the same way as do adults, and that once procedural difficulties are overcome, the standard effects of familiarity are observed.     

Children's perceptions of and beliefs about facial maturity

The author studied children's and young adult's perceptions of facial age and beliefs about the sociability, cognitive ability, and physical fitness of adult faces. From pairs of photographs of adult faces, participants (4-6 years old, 8-10 years old, 13-16 years old, and 19-23 years old) selected the one face that appeared younger, older, better at remembering, smarter, more caring, friendlier, healthier, or stronger. Pairings consisted of faces at different adult age levels (young adults, middle-age adults, older adults, and very old adults.) Older participants were more sensitive to age differences in older faces and to faces more proximal in age. Children and adolescents believed that very old adult faces appeared to be less cognitively able than middle-aged faces (for children) and young adult faces (for adolescents). Very old male faces were judged to be less sociable. Old and very old faces were judged to be less physically fit than young and middle-aged faces. Significant positive correlation coefficients were found between the youngest children's abilities to discriminate between the adult faces of proximal age and youthful biases when selecting faces appearing to be more sociable and cognitively able. The results are discussed with respect to the development of facial information-processing skills and how those skills may be associated with the development of and changes in beliefs about older adults.     

Facial Attention and Spacetime Fragments

Inverting a face impairs perception of its features and recognition of its identity. Whether faces are special in this regard is a current topic of research and debate. Kanizsa studied the role of facial features and environmental context in perceiving the emotion and identity of upright and inverted faces. He found that observers are biased to interpret faces in a retinal coordinate frame, and that this bias is readily overruled by increased realism of facial features, but not easily overruled by environmental context. An additional factor contributing to a retinal coordinate-frame interpretation may be the ambiguous nature of the face stimuli. Since his facial expressions are interpretable both upright and inverted, they may in both orientations activate an endogenous attentional process for faces. We present visual search and change-blindness experiments that explore how inversion, negation, and facial emotion affect visual attention to static faces. We find that attention to faces is impaired by inversion and negation. We also find that the parts of the face that receive greater attention can be influenced by the emotional expression of the face. We propose to extend these experiments to dynamic faces. To this end, we develop a theory of the visual representation of dynamic faces, in which faces are represented by classes of `spacetime fragments'-moving regions of the face with high informational content. We then present ideas for future experiments which are motivated by the spacetime fragment theory, and which should serve to constrain its further development.     

Normal perception of Mooney faces in developmental prosopagnosia: Evidence from the N170 component and rapid neural adaptation

Individuals with developmental prosopagnosia (DP) have a severe difficulty recognizing the faces of known individuals in the absence of any history of neurological damage. These recognition problems may be linked to selective deficits in the holistic/configural processing of faces. We used two‐tone Mooney images to study the processing of faces versus non‐face objects in DP when it is based on holistic information (or the facial gestalt) in the absence of obvious local cues about facial features. A rapid adaptation procedure was employed for a group of 16 DPs. Naturalistic photographs of upright faces were preceded by upright or inverted Mooney faces or by Mooney houses. DPs showed face‐sensitive N170 components in response to Mooney faces versus houses, and N170 amplitude reductions for inverted as compared to upright Mooney faces. They also showed the typical pattern of N170 adaptation effects, with reduced N170 components when upright naturalistic test faces were preceded by upright Mooney faces, demonstrating that the perception of Mooney and naturalistic faces recruits shared neural populations. Our findings demonstrate that individuals with DP can utilize global information about face configurations for categorical discriminations between faces and non‐face objects, and suggest that face processing deficits emerge primarily at more fine‐grained higher level stages of face perception.     

Feature processing and superiority of three-quarter views in face recognition

The specificity of face recognition is usually related to the hypothesis that it could be based mainly on global processing of the whole face. However, this does not mean that more analytic processes, like the local processing of some features, could not play a role in the recognition process in some circumstances. An experiment was conducted with 18 normal subjects in order to evaluate the role of analytic processes in the recognition of faces viewed from different angles. Makeup was applied to eyes and lips to enhance local processing (local cue). We found a positive effect of the makeup cue, which could be due to better recognition when the shape of eyes and lips are highlighted. Also, we found better recognition with left-sided views compared to right-sided views. Finally, the makeup effect was significant in left three-quarter views but not in right three-quarter views. If this effect is due to analytic processing of some facial features, it could be related to a left hemisphere operation.