What gives a face its gender?

An event-related potential investigation of age and sex in face categorization: Participant sex matters

Whether a face is categorized as male or female is influenced by the age of the face. In the present study, Event-Related Potential (ERP) measures were employed to offer insight into the neural correlates indexing the interaction between the age and sex of a face during sex categorization. Thirty-eight young adults (18 male) categorized the sex of young (18-29 years) and older (70-94 years) adult faces as ERP activity was recorded. Amplitude modulation for the P3b was observed in parietal regions. Younger female faces elicited more positive P3b amplitudes than older female faces, a difference that did not occur for male faces. Behavioral performance and P3b modulation also indicated these effects varied between male and female participants. Women responded more slowly and with less accuracy to older female faces compared to male and young female faces, a pattern of results mirrored by P3b latency. These findings indicate that later-occurring ERP components, such as the P3b, signal the intersection of multiple social categories during face processing suggesting that the evaluation of ingroup/outgroup membership related to age is enhanced for young women, but not for young men.

The influence of top-down modulation on the processing of direct gaze

Gaze or eye contact is one of the most important nonverbal social cues, which is fundamental to human social interactions. To achieve real time and dynamic face-to-face communication, our brain needs to process another person's gaze direction rapidly and without explicit instruction. In order to explain the fast and spontaneous processing of direct gaze, the fast-track modulator model was proposed. Here, we review recent developments in gaze processing research in the last decade to extend the fast-track modulator model. In particular, we propose that task demand or top-down modulation could play a more crucial role at gaze processing than formerly assumed. We suggest that under different task demands, top-down modulation can facilitate or interfere with the direct gaze effects for early visual processing. The proposed modification of the model extends the role of task demand and its implication on the direct gaze effect, as well as the need to better control for top-down processing in order to better disentangle the role of top-down and bottom-up processing on the direct gaze effect. This article is categorized under: Cognitive Biology > Evolutionary Roots of Cognition Psychology > Perception and Psychophysics Neuroscience > Cognition.

Sex Categorization of Faces: The Effects of Age and Experience

The face own-age bias effect refers to the better ability to recognize the face from one's own age compared with other age groups. Here we examined whether an own-age advantage occurs for faces sex categorization. We examined 7- and 9-year-olds' and adults' ability to correctly categorize the sex of 7- and 9-year-olds and adult faces without external cues, such as hair. Results indicated that all ages easily classify the sex of adult faces. They succeeded in classifying the sex of child faces, but their performance was poorer than for adult faces. In adults, processing time increased, and a response bias (male response) was elicited for child faces. In children, response times remained constant, and no bias was observed. Experience with specific category of faces seems to offer some advantage in speed of processing. Overall, sex categorization is more challenging for child than for adult faces due to their reduced sexual dimorphic facial characteristics.

Time course of the use of chromatic and achromatic facial information for sex categorization

The most useful facial features for sex categorization are the eyes, the eyebrows, and the mouth. Dupuis-Roy et al. reported a large positive correlation between the use of the mouth region and rapid correct answers [Journal of Vision 9 (2009) 1-8]. Given the chromatic information in this region, they hypothesized that the extraction of chromatic and achromatic cues may have different time courses. Here, we tested this hypothesis directly: 110 participants categorized the sex of 300 face images whose chromatic and achromatic content was partially revealed through time (200 ms) and space using randomly located spatio-temporal Gaussian apertures (i.e. the Bubbles technique). This also allowed us to directly compare, for the first time, the relative importance of chromatic and achromatic facial cues for sex categorization. Results showed that face-sex categorization relies mostly on achromatic (luminance) information concentrated in the eye and eyebrow regions, especially the left eye and eyebrow. Additional analyses indicated that chromatic information located in the mouth/philtrum region was used earlier-peaking as early as 35 ms after stimulus onset-than achromatic information in the eye regions-peaking between 165 and 176 ms after stimulus onset-as was speculated by Dupuis-Roy et al. A non-linear analysis failed to support Yip and Sinha's proposal that processing of chromatic variations can improve subsequent processing of achromatic spatial cues, possibly via surface segmentation [Perception 31 (2002) 995-1003]. Instead, we argue that the brain prioritizes chromatic information to compensate for the sluggishness of chromatic processing in early visual areas, and allow chromatic and achromatic information to reach higher-level visual areas simultaneously.

Inter-rater agreement in trait judgements from faces

Researchers have long been interested in how social evaluations are made based upon first impressions of faces. It is also important to consider the level of agreement we see in such evaluations across raters and what this may tell us. Typically, high levels of inter-rater agreement for facial judgements are reported, but the measures used may be misleading. At present, studies commonly report Cronbach's α as a way to quantify agreement, although problematically, there are various issues with the use of this measure. Most importantly, because researchers treat raters as items, Cronbach's α is inflated by larger sample sizes even when agreement between raters is fixed. Here, we considered several alternative measures and investigated whether these better discriminate between traits that were predicted to show low (parental resemblance), intermediate (attractiveness, dominance, trustworthiness), and high (age, gender) levels of agreement. Importantly, the level of inter-rater agreement has not previously been studied for many of these traits. In addition, we investigated whether familiar faces resulted in differing levels of agreement in comparison with unfamiliar faces. Our results suggest that alternative measures may prove more informative than Cronbach's α when determining how well raters agree in their judgements. Further, we found no apparent influence of familiarity on levels of agreement. Finally, we show that, like attractiveness, both trustworthiness and dominance show significant levels of private taste (personal or idiosyncratic rater perceptions), although shared taste (perceptions shared with other raters) explains similar levels of variance in people's perceptions. In conclusion, we recommend that researchers investigating social judgements of faces consider alternatives to Cronbach's α but should also be prepared to examine both the potential value and origin of private taste as these might prove informative.

Feminização, estigma e o gênero facializado: a construção moral do gênero feminino por meio de cirurgias de feminização facial para travestis e mulheres transexuais

Resumo Este artigo objetiva analisar os discursos de gênero construídos em torno das chamadas “cirurgias de feminização facial” tanto pelo discurso científico biomédico como por clínicas que oferecem tais procedimentos, os quais têm se tornado bastante populares entre travestis e mulheres transexuais. A partir de levantamento bibliográfico feito no website Google Acadêmico, inicialmente analiso artigos científicos do campo biomédico que buscam construir uma noção de gênero - ou uma identificação de gênero - por meio do conjunto dos traços faciais. Essa literatura biomédica fornece as bases a partir das quais profissionais e clínicas médicas construirão discursos e práticas acerca da “necessidade” e, por conseguinte, de um desejo desse tipo de intervenção para travestis e mulheres transexuais. Na sequência, analiso como tal discurso é encarnado (embodied) na descrição e na técnica dos procedimentos cirúrgicos da dita feminização facial a partir de material etnográfico de tese de doutorado sobre o Miss T Brasil, concurso de beleza voltado para travestis e mulheres transexuais. Os resultados demonstram que tanto o saber biomédico como as práticas em torno de tais cirurgias se pautam em ideais de constituição de uma “naturalidade” nos traços faciais e preservação de uma identidade reconhecida como pessoal. Constrói-se e visibiliza-se, assim, determinada feminilidade para travestis e mulheres transexuais que tanto parece corresponder a desejos pessoais de se alcançar um ideal normativo e socialmente validado de feminino, ao mesmo tempo que se promoveria o encobrimento de um estigma ao se permitir que elas “passem por” mulher em uma relação social ordinária.

Selective Attention to Faces in a Rapid Visual Stream: Hemispheric Differences in Enhancement and Suppression of Category-selective Neural Activity

In daily life, efficient perceptual categorization of faces occurs in dynamic and highly complex visual environments. Yet the role of selective attention in guiding face categorization has predominantly been studied under sparse and static viewing conditions, with little focus on disentangling the impact of attentional enhancement and suppression. Here we show that attentional enhancement and suppression exert a differential impact on face categorization supported by the left and right hemispheres. We recorded 128-channel EEG while participants viewed a 6-Hz stream of object images (buildings, animals, objects, etc.) with a face image embedded as every fifth image (i.e., OOOOFOOOOFOOOOF…). We isolated face-selective activity by measuring the response at the face presentation frequency (i.e., 6 Hz/5 = 1.2 Hz) under three conditions: Attend Faces, in which participants monitored the sequence for instances of female faces; Attend Objects, in which they responded to instances of guitars; and Baseline, in which they performed an orthogonal task on the central fixation cross. During the orthogonal task, face-specific activity was predominantly centered over the right occipitotemporal region. Actively attending to faces enhanced face-selective activity much more evidently in the left hemisphere than in the right, whereas attending to objects suppressed the face-selective response in both hemispheres to a comparable extent. In addition, the time courses of attentional enhancement and suppression did not overlap. These results suggest the left and right hemispheres support face-selective processing in distinct ways—where the right hemisphere is mandatorily engaged by faces and the left hemisphere is more flexibly recruited to serve current tasks demands.

Technical and Clinical Considerations for Facial Feminization Surgery With Rhinoplasty and Related Procedures

IMPORTANCE

Together with the forehead reconstruction, feminization of the nose is one of the most common procedures in facial feminization surgery. Rhinoplasty surgical techniques, which provide correct support and stability in the midterm to long term, are essential for obtaining a predictable result.

OBJECTIVE

To report on the technical and clinical considerations of rhinoplasty and related procedures to feminize the nose, harmonize the nose in relation to the other modified structures (mainly the forehead and maxillomandibular complex), and achieve an aesthetic result beyond gender differences.

DESIGN, SETTING, AND PARTICIPANTS

Case series study of feminization rhinoplasties, in combination with lip-lift techniques, forehead reconstruction, and other procedures, were performed at a private practice between January 11, 2010, and May 29, 2015, in 200 consecutive male-to-female transgender patients. The mean (SD) medical follow-up for patients was 32 (18.84) months (range, 12-77 months). Frontonasal angles were objectively measured. Postoperative and long-term patient satisfaction were assessed.

MAIN OUTCOMES AND MEASURES

Clinical analysis and evaluation using the 5-point Nose Feminization Scale, with 1 indicating very masculine or nose is worse and 5 indicating very feminine or exceptional result.

RESULTS

In these 200 patients, the mean (SD) age was 40.2 (12.2) years (range, 18-70 years). The mean (SE) frontonasal angle changed from 133.64° (0.63°) to 149.08° (0.57°) (difference in means, -15.44; 95% CI, -17.12 to -13.76; P < .001). Most patients considered their nose to appear more feminine after the surgery, and the degree of satisfaction after the rhinoplasty was 4 (much better) of 5 points on the Nose Feminization Scale. During the evaluation of feminization rhinoplasties, special attention was given to how the nose relates to other features essential to the identification of facial gender: the forehead and maxillomandibular complex. Emphasis was placed on the midterm to long-term stability of the results by reinforcing the internal structure.

CONCLUSIONS AND RELEVANCE

In this case series of feminization rhinoplasties in combination with lip-lift techniques and forehead reconstruction, frontonasal angles were changed, and patient satisfaction with outcomes was high. The main goal of rhinoplasty in facial feminization surgery is to obtain feminine nasal features and the harmonization of the nose with the rest of the face. Lip-lifts and frontonasal recontouring can complement rhinoplasties associated with facial feminization surgery.

LEVEL OF EVIDENCE

4.

Facial Feminization: Systematic Review of the Literature

BACKGROUND

Facial feminization surgery encompasses a broad range of craniomaxillofacial surgical procedures designed to change masculine facial features into feminine features. The surgical principles of facial feminization surgery can be applied to male-to-female transsexuals and anyone desiring feminization of the face. Although the prevalence of these procedures is difficult to quantify, because of the rising prevalence of transgenderism (approximately one in 14,000 men) along with improved insurance coverage for gender-confirming surgery, surgeons versed in techniques, outcomes, and challenges of facial feminization surgery are needed. This review is designed to critically appraise the current facial feminization surgery literature.

METHODS

A comprehensive literature search of the Medline, PubMed, and EMBASE databases was conducted for studies published through October of 2014 with multiple search terms related to facial feminization. Data on techniques, outcomes, complications, and patient satisfaction were collected.

RESULTS

Fifteen articles were selected and reviewed from the 24 identified, all of which were either retrospective or case series/reports. Articles covered a variety of facial feminization procedures. A total of 1121 patients underwent facial feminization surgery, with seven complications reported, although many articles did not explicitly comment on complications. Satisfaction was high, although most studies did not use validated or quantified approaches to address satisfaction.

CONCLUSIONS

Facial feminization surgery appears to be safe and satisfactory for patients. Further studies are required to better compare different techniques to more robustly establish best practices. Prospective studies and patient-reported outcomes are needed to establish quality-of-life outcomes for patients. However, based on these studies, it appears that facial feminization surgery is highly efficacious and beneficial to patients.

Patterns of correlation of facial shape with physiological measurements are more integrated than patterns of correlation with ratings

This article exploits a method recently incorporated in the geometric morphometric toolkit that complements previous approaches to quantifying the facial features associated with specific body characteristics and trait attribution during social perception. The new method differentiates more globally encoded from more locally encoded information by a summary scaling dimension that is estimated by fitting a line to the plot of log bending energy against log variance explained, partial warp by partial warp, for some sample of varying shapes. In the present context these variances come from the regressions of shape on some exogenous cause or effect of form. We work an example involving data from male faces. Here the regression slopes are steepest, and the sums of explained variances over the uniform component, partial warp 1 and partial warp 2 are greatest, for the conventional body mass index, followed by cortisol and, lastly, perceived health. This suggests that physiological characteristics may be represented at larger scale (global patterns), whereas cues in perception are of smaller scale (local patterns). Such a polarity within psychomorphospace, the global versus the focal, now has a metric by which patterns of morphology can be modeled in both biological and psychological studies.

Audio-Visual Perception of Gender by Infants Emerges Earlier for Adult-Directed Speech

Early multisensory perceptual experiences shape the abilities of infants to perform socially-relevant visual categorization, such as the extraction of gender, age, and emotion from faces. Here, we investigated whether multisensory perception of gender is influenced by infant-directed (IDS) or adult-directed (ADS) speech. Six-, 9-, and 12-month-old infants saw side-by-side silent video-clips of talking faces (a male and a female) and heard either a soundtrack of a female or a male voice telling a story in IDS or ADS. Infants participated in only one condition, either IDS or ADS. Consistent with earlier work, infants displayed advantages in matching female relative to male faces and voices. Moreover, the new finding that emerged in the current study was that extraction of gender from face and voice was stronger at 6 months with ADS than with IDS, whereas at 9 and 12 months, matching did not differ for IDS versus ADS. The results indicate that the ability to perceive gender in audiovisual speech is influenced by speech manner. Our data suggest that infants may extract multisensory gender information developmentally earlier when looking at adults engaged in conversation with other adults (i.e., ADS) than when adults are directly talking to them (i.e., IDS). Overall, our findings imply that the circumstances of social interaction may shape early multisensory abilities to perceive gender.

Population Coding of Facial Information in the Monkey Superior Colliculus and Pulvinar

The superior colliculus (SC) and pulvinar are thought to function as a subcortical visual pathway that bypasses the striate cortex and detects fundamental facial information. We previously investigated neuronal responses in the SC and pulvinar of monkeys during a delayed nonmatching-to-sample task, in which the monkeys were required to discriminate among 35 facial photos of five models and other categories of visual stimuli, and reported that population coding by multiple SC and pulvinar neurons well discriminated facial photos from other categories of stimuli (Nguyen et al., 2013, 2014). However, it remains unknown whether population coding could represent multiple types of facial information including facial identity, gender, facial orientation, and gaze direction. In the present study, to investigate population coding of multiple types of facial information by the SC and pulvinar neurons, we reanalyzed the same neuronal responses in the SC and pulvinar; the responses of 112 neurons in the SC and 68 neurons in the pulvinar in serial 50-ms epochs after stimulus onset were reanalyzed with multidimensional scaling (MDS). The results indicated that population coding by neurons in both the SC and pulvinar classified some aspects of facial information, such as face orientation, gender, and identity, of the facial photos in the second epoch (50–100 ms after stimulus onset). The Euclidean distances between all the pairs of stimuli in the MDS spaces in the SC were significantly correlated with those in the pulvinar, which suggested that the SC and pulvinar function as a unit. However, in contrast with the known population coding of face neurons in the temporal cortex, the facial information coding in the SC and pulvinar was coarse and insufficient. In these subcortical areas, identity discrimination was face orientation-dependent and the left and right profiles were not discriminated. Furthermore, gaze direction information was not extracted in the SC and pulvinar. These results suggest that the SC and pulvinar, which comprise the subcortical visual pathway, send coarse and rapid information on faces to the cortical system in a bottom-up process.

What's in a Face? How Face Gender and Current Affect Influence Perceived Emotion

Faces drive our social interactions. A vast literature suggests an interaction between gender and emotional face perception, with studies using different methodologies demonstrating that the gender of a face can affect how emotions are processed. However, how different is our perception of affective male and female faces? Furthermore, how does our current affective state when viewing faces influence our perceptual biases? We presented participants with a series of faces morphed along an emotional continuum from happy to angry. Participants judged each face morph as either happy or angry. We determined each participant's unique emotional 'neutral' point, defined as the face morph judged to be perceived equally happy and angry, separately for male and female faces. We also assessed how current state affect influenced these perceptual neutral points. Our results indicate that, for both male and female participants, the emotional neutral point for male faces is perceptually biased to be happier than for female faces. This bias suggests that more happiness is required to perceive a male face as emotionally neutral, i.e., we are biased to perceive a male face as more negative. Interestingly, we also find that perceptual biases in perceiving female faces are correlated with current mood, such that positive state affect correlates with perceiving female faces as happier, while we find no significant correlation between negative state affect and the perception of facial emotion. Furthermore, we find reaction time biases, with slower responses for angry male faces compared to angry female faces.

Faces on Her and His Mind: Female and Likable

Faces are a valuable source of non-verbal information for daily life social interaction. Mounting evidence points to gender specificity in face perception. Here we search for the factors that can potentially trigger gender differences in tuning to faces. By using a set of Face-n-Food images slightly bordering on the Giuseppe Arcimboldo style, we examine: (i) whether face resemblance is linked to gender specific face impression, and, if so, whether this association is perceiver gender specific; and (ii) whether images most resembling a face are also most likable for female and male perceivers. First, in a spontaneous recognition task, participants were shown a set of Face-n-Food images in a predetermined order from the least to most resembling a face. Then in a two-alternative forced-choice (2AFC) task, participants judged whether each face appeared for them (i) either female or male (Exp. 1); or (ii) either likable or unlikable (Exp. 2). Remarkably, face resemblance is closely connected to gender specific impressions: images more resembling a face elicit also more female-face responses. This link is not perceiver gender specific as it occurs for both females and males. Moreover, face resemblance is positively linked to face likability, but this holds true only for female perceivers. The findings shed light on gender specificity in tuning to faces, and help to clarify abnormalities of the social brain in neurodevelopmental, psychiatric and psychosomatic disorders.

Configural Information in Gender Categorisation

The role of configural information in gender categorisation was studied by aligning the top half of one face with the bottom half of another. The two faces had the same or different genders. Experiment l shows that participants were slower and made more errors in categorising the gender in either half of these composite faces when the two faces had a different gender, relative to control conditions where the two faces were nonaligned or had the same gender. This result parallels the composite effect for face recognition (Young et al, 1987 Perception16 747–759) and facial-expression recognition (Calder et al, 2000 Journal of Experimental Psychology: Human Perception and Performance26 527–551). Similarly to responses to face identity and expression, the composite effect on gender discrimination was disrupted by inverting the faces (experiment 2). Both experiments also show that the composite paradigm is sensitive to general contextual interference in gender categorisation.

Perception of Multisensory Gender Coherence in 6- and 9-month-old Infants

One of the most salient social categories conveyed by human faces and voices is gender. We investigated the developmental emergence of the ability to perceive the coherence of auditory and visual attributes of gender in 6- and 9-month-old infants. Infants viewed two side-by-side video clips of a man and a woman singing a nursery rhyme and heard a synchronous male or female soundtrack. Results showed that 6-month-old infants did not match the audible and visible attributes of gender, and 9-month-old infants matched only female faces and voices. These findings indicate that the ability to perceive the multisensory coherence of gender emerges relatively late in infancy and that it reflects the greater experience that most infants have with female faces and voices.

My Brain Reads Pain in Your Face, Before Knowing Your Gender

Humans are expert at recognizing facial features whether they are variable (emotions) or unchangeable (gender). Because of its huge communicative value, pain might be detected faster in faces than unchangeable features. Based on this assumption, we aimed to find a presentation time that enables subliminal discrimination of pain facial expression without permitting gender discrimination. For 80 individuals, we compared the time needed (50, 100, 150, or 200 milliseconds) to discriminate masked static pain faces among anger and neutral faces with the time needed to discriminate male from female faces. Whether these discriminations were associated with conscious reportability was tested with confidence measures on 40 other individuals. The results showed that, at 100 milliseconds, 75% of participants discriminated pain above chance level, whereas only 20% of participants discriminated the gender. Moreover, this pain discrimination appeared to be subliminal. This priority of pain over gender might exist because, even if pain faces are complex stimuli encoding both the sensory and the affective component of pain, they signal a danger. This supports the evolution theory relating to the necessity of quickly reading aversive emotions to ensure survival but might also be at the basis of altruistic behavior such as help and compassion.

PERSPECTIVE

This study shows that pain facial expression can be processed subliminally after brief presentation times, which might be helpful for critical emergency situations in clinical settings.

Fixation to features and neural processing of facial expressions in a gender discrimination task

Early face encoding, as reflected by the N170 ERP component, is sensitive to fixation to the eyes. Whether this sensitivity varies with facial expressions of emotion and can also be seen on other ERP components such as P1 and EPN, was investigated. Using eye-tracking to manipulate fixation on facial features, we found the N170 to be the only eye-sensitive component and this was true for fearful, happy and neutral faces. A different effect of fixation to features was seen for the earlier P1 that likely reflected general sensitivity to face position. An early effect of emotion (∼120 ms) for happy faces was seen at occipital sites and was sustained until ∼350 ms post-stimulus. For fearful faces, an early effect was seen around 80 ms followed by a later effect appearing at ∼150 ms until ∼300 ms at lateral posterior sites. Results suggests that in this emotion-irrelevant gender discrimination task, processing of fearful and happy expressions occurred early and largely independently of the eye-sensitivity indexed by the N170. Processing of the two emotions involved different underlying brain networks active at different times.

The independence of expression and identity in face-processing: evidence from neuropsychological case studies

The processing of facial identity and facial expression have traditionally been seen as independent—a hypothesis that has largely been informed by a key double dissociation between neurological patients with a deficit in facial identity recognition but not facial expression recognition, and those with the reverse pattern of impairment. The independence hypothesis is also reflected in more recent anatomical models of face-processing, although these theories permit some interaction between the two processes. Given that much of the traditional patient-based evidence has been criticized, a review of more recent case reports that are accompanied by neuroimaging data is timely. Further, the performance of individuals with developmental face-processing deficits has recently been considered with regard to the independence debate. This paper reviews evidence from both acquired and developmental disorders, identifying methodological and theoretical strengths and caveats in these reports, and highlighting pertinent avenues for future research.

Aging affects sex categorization of male and female faces in opposite ways

Faces are rich in social information; they easily give away a person's sex, approximate age, feelings, or focus of attention. Past research has mostly focused on investigating the distinct facial signals and perceptual mechanisms that allow us to categorize faces on these individual dimensions. It is less well understood how the different kinds of facial information interact. Here we investigated how the age of a face affects the ease with which young and older adults categorize its sex. Disconfirming everyday intuition, we showed that sex categorization is not generally hampered for older faces. Although categorization of female faces took progressively more time with increasing age, the opposite was found for male faces (Experiment 1). Differential effects of stimulus blurring and inversion for male and female faces of different ages (Experiment 2) strongly suggest one feature as a crucial mediator of the interdependence of age and sex perception - skin texture.

Demographic Estimation from Face Images: Human vs. Machine Performance

Demographic estimation entails automatic estimation of age, gender and race of a person from his face image, which has many potential applications ranging from forensics to social media. Automatic demographic estimation, particularly age estimation, remains a challenging problem because persons belonging to the same demographic group can be vastly different in their facial appearances due to intrinsic and extrinsic factors. In this paper, we present a generic framework for automatic demographic (age, gender and race) estimation. Given a face image, we first extract demographic informative features via a boosting algorithm, and then employ a hierarchical approach consisting of between-group classification, and within-group regression. Quality assessment is also developed to identify low-quality face images that are difficult to obtain reliable demographic estimates. Experimental results on a diverse set of face image databases, FG-NET (1K images), FERET (3K images), MORPH II (75K images), PCSO (100K images), and a subset of LFW (4K images), show that the proposed approach has superior performance compared to the state of the art. Finally, we use crowdsourcing to study the human perception ability of estimating demographics from face images. A side-by-side comparison of the demographic estimates from crowdsourced data and the proposed algorithm provides a number of insights into this challenging problem.

The effects of a culturally gender-specifying peripheral cue (headscarf) on the categorization of faces by gender

Faces convey a wealth of cues that influence social categorizations and subsequent cognition and behavior. This study examined the effects of wearing a headscarf on face categorization by gender using Egyptian observers who have an extensive exposure with headscarf-framed female faces. A typical headscarf (worn by females) enhanced perceived femininity whereas an atypical headscarf (worn by males) reduced perceived masculinity. Regardless of whether the faces were presented briefly, or until participants responded, the typical headscarf had no effect on categorizing female faces but the atypical headscarf greatly slowed down categorizing male faces. However, a typical headscarf advantage was noticed when the atypical headscarf condition was removed. In addition, both typical and atypical headscarf effects were greatly strengthened when faces were presented as negatives. These data provide support to the dynamic continuity account of social categorization that suggests a competition among multiple simultaneous representations until a construal is stabilized.

Face recognition in schizophrenia disorder: A comprehensive review of behavioral, neuroimaging and neurophysiological studies

Facial emotion processing has been extensively studied in schizophrenia patients while general face processing has received less attention. The already published reviews do not address the current scientific literature in a complete manner. Therefore, here we tried to answer some questions that remain to be clarified, particularly: are the non-emotional aspects of facial processing in fact impaired in schizophrenia patients? At the behavioral level, our key conclusions are that visual perception deficit in schizophrenia patients: are not specific to faces; are most often present when the cognitive (e.g. attention) and perceptual demands of the tasks are important; and seems to worsen with the illness chronification. Although, currently evidence suggests impaired second order configural processing, more studies are necessary to determine whether or not holistic processing is impaired in schizophrenia patients. Neural and neurophysiological evidence suggests impaired earlier levels of visual processing, which might involve the deficits in interaction of the magnocellular and parvocellular pathways impacting on further processing. These deficits seem to be present even before the disorder out-set. Although evidence suggests that this deficit may be not specific to faces, further evidence on this question is necessary, in particularly more ecological studies including context and body processing.

Face features and face configurations both contribute to visual crowding

Crowding refers to the inability to recognize an object in peripheral vision when other objects are presented nearby (Whitney & Levi Trends in Cognitive Sciences, 15, 160-168, 2011). A popular explanation of crowding is that features of the target and flankers are combined inappropriately when they are located within an integration field, thus impairing target recognition (Pelli, Palomares, & Majaj Journal of Vision, 4(12), 12:1136-1169, 2004). However, it remains unclear which features of the target and flankers are combined inappropriately to cause crowding (Levi Vision Research, 48, 635-654, 2008). For example, in a complex stimulus (e.g., a face), to what extent does crowding result from the integration of features at a part-based level or at the level of global processing of the configural appearance? In this study, we used a face categorization task and different types of flankers to examine how much the magnitude of visual crowding depends on the similarity of face parts or of global configurations. We created flankers with face-like features (e.g., the eyes, nose, and mouth) in typical and scrambled configurations to examine the impacts of part appearance and global configuration on the visual crowding of faces. Additionally, we used "electrical socket" flankers that mimicked first-order face configuration but had only schematic features, to examine the extent to which global face geometry impacted crowding. Our results indicated that both face parts and configurations contribute to visual crowding, suggesting that face similarity as realized under crowded conditions includes both aspects of facial appearance.

The Intersection of Gender-Related Facial Appearance and Facial Displays of Emotion

The human face conveys a myriad of social meanings within an overlapping array of features. Herein, we examine such features within the context of gender-emotion stereotypes. First we detail the pervasive set of gender-emotion expectations known to exist. We then review new research revealing that gender cues and emotion expression often share physical properties that represent a confound of overlapping features characteristic of low versus high facial maturity/dominance. As such, gender-related facial appearance and facial expression of emotions often share social meaning and physical resemblance. Thus, stereotypic and phenotypic information conveyed by the face are intertwined—sometimes confounded, sometimes clashing. We discuss implications of this work for gender-emotion stereotypes, as well as for emotion and face processing more generally.

Physical Aggression and Facial Expression Identification

Social information processing theories suggest that aggressive individuals may exhibit hostile perceptual biases when interpreting other’s behaviour. This hypothesis was tested in the present study which investigated the effects of physical aggression on facial expression identification in a sample of healthy participants. Participants were asked to judge the expressions of faces presented to them and to complete a self-report measure of aggression. Relative to low physically aggressive participants, high physically aggressive participants were more likely to mistake non-angry facial expressions as being angry facial expressions (misattribution errors), supporting the idea of a hostile predisposition. These differences were not explained by gender, or response times. There were no differences in identifying angry expressions in general between aggression groups (misperceived errors). These findings add support to the idea that aggressive individuals exhibit hostile perceptual biases when interpreting facial expressions.

Female face preference in 4-month-olds: the importance of hairline

At 3-4 months of age, infants respond to gender information in human faces. Specifically, young infants display a visual preference toward female over male faces. In three experiments, using a visual preference task, we investigated the role of hairline information in this bias. In Experiment 1, we presented male and female composite faces with similar hairstyles to 4-month-olds and observed a preference for female faces. In Experiment 2, the faces were presented, but in this instance, without hairline cues, and the preference was eliminated. In Experiment 3, using the same cropping to eliminate hairline cues, but with feminized female faces and masculinized male faces, infants' preference toward female faces was still not in evidence. The findings show that hairline information is important in young infants' preferential orientation toward female faces.

A critical role of holistic processing in face gender perception

Whether face gender perception is processed by encoding holistic (whole) or featural (parts) information is a controversial issue. Although neuroimaging studies have identified brain regions related to face gender perception, the temporal dynamics of this process remain under debate. Here, we identified the mechanism and temporal dynamics of face gender perception. We used stereoscopic depth manipulation to create two conditions: the front and behind condition. In the front condition, facial patches were presented stereoscopically in front of the occluder and participants perceived them as disjoint parts (featural cues). In the behind condition, facial patches were presented stereoscopically behind the occluder and were amodally completed and unified in a coherent face (holistic cues). We performed three behavioral experiments and one electroencephalography experiment, and compared the results of the front and behind conditions. We found faster reaction times (RTs) in the behind condition compared with the front, and observed priming effects and aftereffects only in the behind condition. Moreover, the EEG experiment revealed that face gender perception is processed in the relatively late phase of visual recognition (200-285 ms). Our results indicate that holistic information is critical for face gender perception, and that this process occurs with a relatively late latency.

Altering second-order configurations reduces the adaptation effects on early face-sensitive event-related potential components

The spatial distances among the features of a face are commonly referred to as second-order relations, and the coding of these properties is often regarded as a cornerstone in face recognition. Previous studies have provided mixed results regarding whether the N170, a face-sensitive component of the event-related potential, is sensitive to second-order relations. Here we investigated this issue in a gender discrimination paradigm following long-term (5 s) adaptation to normal or vertically stretched male and female faces, considering that the latter manipulation substantially alters the position of the inner facial features. Gender-ambiguous faces were more likely judged to be female following adaptation to a male face and vice versa. This aftereffect was smaller but statistically significant after being adapted to vertically stretched when compared to unstretched adapters. Event-related potential recordings revealed that adaptation effects measured on the amplitude of the N170 show strong modulations by the second-order relations of the adapter: reduced N170 amplitude was observed, however, this reduction was smaller in magnitude after being adapted to stretched when compared to unstretched faces. These findings suggest early face-processing, as reflected in the N170 component, proceeds by extracting the spatial relations of inner facial features.

Judgment of gender through facial parts

Japanese male and female undergraduate students judged the gender of a variety of facial images. These images were combinations of the following facial parts: eyebrows, eyes, nose, mouth, and the face outline (cheek and chin). These parts were extracted from averaged facial images of Japanese males and females aged 18 and 19 years by means of the Facial Image Processing System. The results suggested that, in identifying gender, subjects performed identification on the basis of the eyebrows and the face outline, and both males and females were more likely to identify the faces as those of their own gender. The results are discussed in relation to previous studies, with particular attention paid to the matter of race differences.

Perceptual and gaze biases during face processing: related or not?

Previous studies have demonstrated a left perceptual bias while looking at faces, due to the fact that observers mainly use information from the left side of a face (from the observer's point of view) to perform a judgment task. Such a bias is consistent with the right hemisphere dominance for face processing and has sometimes been linked to a left gaze bias, i.e. more and/or longer fixations on the left side of the face. Here, we recorded eye-movements, in two different experiments during a gender judgment task, using normal and chimeric faces which were presented above, below, right or left to the central fixation point or on it (central position). Participants performed the judgment task by remaining fixated on the fixation point or after executing several saccades (up to three). A left perceptual bias was not systematically found as it depended on the number of allowed saccades and face position. Moreover, the gaze bias clearly depended on the face position as the initial fixation was guided by face position and landed on the closest half-face, toward the center of gravity of the face. The analysis of the subsequent fixations revealed that observers move their eyes from one side to the other. More importantly, no apparent link between gaze and perceptual biases was found here. This implies that we do not look necessarily toward the side of the face that we use to make a gender judgment task. Despite the fact that these results may be limited by the absence of perceptual and gaze biases in some conditions, we emphasized the inter-individual differences observed in terms of perceptual bias, hinting at the importance of performing individual analysis and drawing attention to the influence of the method used to study this bias.

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.

The development of facial gender categorization in individuals with and without autism: the impact of typicality

While much research has examined the development of facial recognition abilities, less is known about the ability of individuals with and without autism to categorize facial gender. The current study tested gender categorization abilities in high-functioning children (5-7 and 8-12 years), adolescents (13-17 years), and adults (18-53 years) with autism and matched controls. Naturalistic videos depicted faces that were either typical or less typical of each gender. Both groups improved in their performance across development. However, control children reached expertise that was similar to control adults by 8-12 years; whereas, adults with autism never reached this level of expertise, particularly with less typical gender faces. Results suggest that individuals with autism employ different face processing mechanisms than typically developing individuals.

Effects of Spatial Frequency Content on Classification of Face Gender and Expression

The role of different spatial frequency bands on face gender and expression categorization was studied in three experiments. Accuracy and reaction time were measured for unfiltered, low-pass (cut-off frequency of 1 cycle/deg) and high-pass (cut-off frequency of 3 cycles/deg) filtered faces. Filtered and unfiltered faces were equated in root-mean-squared contrast. For low-pass filtered faces reaction times were higher than unfiltered and high-pass filtered faces in both categorization tasks. In the expression task, these results were obtained with expressive faces presented in isolation (Experiment 1) and also with neutral-expressive dynamic sequences where each expressive face was preceded by a briefly presented neutral version of the same face (Experiment 2). For high-pass filtered faces different effects were observed on gender and expression categorization. While both speed and accuracy of gender categorization were reduced comparing to unfiltered faces, the efficiency of expression classification remained similar. Finally, we found no differences between expressive and non expressive faces in the effects of spatial frequency filtering on gender categorization (Experiment 3). These results show a common role of information from the high spatial frequency band in the categorization of face gender and expression.

Identification accuracy for single- and double-perpetrator crimes: does accomplice gender matter?

There is an important mismatch between empirical research on the accuracy of eyewitness identification and the real world of criminal investigation. Most research models single-perpetrator crimes, but in the real world, most crimes involve multiple perpetrators. This study examined how the number of perpetrators affects eyewitness identification by manipulating the gender of accomplices. Observers viewed a video of a staged crime. The crime was committed by a male or female perpetrator, who was presented alone or with an accomplice of the same or the opposite gender. The observers were then asked to identify the perpetrators from target-present or target-absent line-ups. The results revealed a double-perpetrator disadvantage, which was manifested in reduced identification accuracy on target-present line-ups. Importantly, however, the gender of the perpetrator or the accomplice had no effect on this disadvantage. This double-perpetrator disadvantage is attributed to the need to divide attention between two concurrent people, compared to single-culprit crimes, rather than an impairment of visual encoding processes. The implications of these findings are discussed.