Real-world face recognition: the importance of surface reflectance properties

The face recognition task we perform [corrected] most often in everyday experience is the identification of people with whom we are familiar. However, because of logistical challenges, most studies focus on unfamiliar-face recognition, wherein subjects are asked to match or remember images of unfamiliar people's faces. Here we explore the importance of two facial attributes -shape and surface reflectance-in the context of a familiar-face recognition task. In our experiment, subjects were asked to recognise color images of the faces of their friends. The images were manipulated such that only reflectance or only shape information was useful for recognizing any particular face. Subjects were actually better at recognizing their friends' faces from reflectance information than from shape information. This provides evidence that reflectance information is important for face recognition in ecologically relevant contexts.     

Familiarity,Target Set and False Positives in Face Recognition

Distinctiveness of a face predicts both miss errors (MEs) and false positives (FPs) but correlations between these errors are low (e.g. Hancock, Burton, & Bruce, 1996). To investigate this, distinctiveness and personal familiarity were analysed as predictors of MEs and FPs in a face recognition experiment. Faces were assigned to three groups, which meant that each set were distractor faces for two different sets of targets. Mean ratings of distinctiveness predicted MEs, whereas familiarity predicted FPs only if individual ratings were used. The degree to which subjects were consistent in their ratings and performance over different faces was also considered. Good subject consistency was found on FPs when the subjects saw the same target faces. If subjects who had seen different target faces were compared, then the consistency of FPs was lower than the consistency of MEs. The results imply that distinctiveness predicts MEs as a general property of the population of faces, whereas familiarity predicts FPs according to the idiosyncrasies of subjects.     

InterFace: A software package for face image warping,averaging, and principal components analysis

We describe InterFace, a software package for research in face recognition. The package supports image warping, reshaping, averaging of multiple face images, and morphing between faces. It also supports principal components analysis (PCA) of face images, along with tools for exploring the “face space” produced by PCA. The package uses a simple graphical user interface, allowing users to perform these sophisticated image manipulations without any need for programming knowledge. The program is available for download in the form of an app, which requires that users also have access to the (freely available) MATLAB Runtime environment.     

Computer graphic studies of the role of facial similarity in judgements of attractiveness

Anecdotally, spouses are often said to resemble one another. This study investigates the effects of similarity between participants and stimuli on judgements of facial attractiveness: does “like prefer like”? Using computer graphic techniques, opposite sex facial stimuli were generated from subjects' photographs. Experiment 1 showed a correlation between attractiveness and similarity but the effect can be explained by the attractiveness of average faces. Beyond this, there was a trend for individual subjects to rate opposite sex images with a similar face shape to their own face as more attractive than other subjects. Experiment 2 allowed subjects to interactively manipulate an opposite sex facial image along a continuum from a self-similar shape, through an average face shape, to a face with opposite characteristics. No significant preferences for self-similar or opposite characteristics were found. Preferences for average faces are stronger than preferences for self-similar faces.     

信息类型和位置对儿童不同时期面孔加工的作用

采用多维面孔任务（face dimensions task）探讨了信息类型和位置对7～17岁儿童面孔加工的作用。该任务通过改变面孔的类型信息（特征和结构）和位置信息（眼部和嘴部）,要求儿童对同时呈现的面孔图片进行“相同”或“不同”的判断。研究发现,儿童面孔加工水平随年龄提高,13～14岁表现最好;对面孔特征的加工好于结构加工,而眼部和嘴部的加工差异从11～12岁开始出现;类型信息和位置信息共同作用于面孔加工,表现为儿童在嘴部的特征和结构加工上未出现显著差异,但眼部的特征加工显著好于眼部的结构加工。     

Manipulation of colour and shape information and its consequence upon recognition and best-likeness judgments

Previous forays into the study of recognition have revealed an advantage for line-drawn and photographic shape caricatures of faces in reaction-time paradigms. When a presentation-time technique was used, photographs with enhanced colour intensity and saturation were also found to provide superior recognition accuracy to veridical images. This has provided strong evidence that distinctive information can produce a recognition advantage for famous faces in both colour and shape domains. Such a presentation-time paradigm allows the display of stimuli over a range of brief display periods. Using this paradigm, subjects recognised photorealistic target faces caricatured in shape with greater accuracy than veridical images, consistent with previous findings when reaction time was used as a measure. Subjects were also asked to identify the best likeness for individuals using photorealistic stimuli and an interactive paradigm with shape caricature, colour caricature, and contrast control varied by the user in real-time. The best likeness with shape manipulation was a slight anticaricature, while with colour-caricature and contrast-control images a mildly exaggerated image was selected as the best likeness. Thus, although images caricatured substantially in colour or shape (+40%) induce superior recognition compared to veridical images, such substantial exaggerations are not necessarily seen as best likenesses under prolonged exposure.     

Adaptation and the perception of facial age

We examined how the perceived age of adult faces is affected by adaptation to younger or older adult faces. Observers viewed images of a synthetic male face simulating ageing over a modelled range from 15 to 65 years. Age was varied by changing shape cues or textural cues. Age level was varied in a staircase to find the observer's subjective category boundary between “old” and “young”. These boundaries were strongly biased by adaptation to the young or old face, with significant aftereffects induced by either shape or textural cues. A further experiment demonstrated comparable aftereffects for photorealistic images of average older or younger adult faces, and found that aftereffects showed some selectivity for a change in gender but also strongly transferred across gender. This transfer shows that adaptation can adjust to the attribute of age somewhat independently of other facial attributes. These findings suggest that perceived age, like many other natural facial dimensions, is highly susceptible to adaptation, and that this adaptation can be carried by both the structural and textural changes that normally accompany facial ageing.     

Crucial information for efficient face searching by humans and Japanese macaques

Humans can efficiently detect a face among non-face objects, but few studies of this ability have been conducted in animals. Here, in Japanese macaques and humans, we examined visual searching for a face and explored what factors contribute to efficient facial information processing. Subjects were asked to search for an odd target among the different numbers of distracters. Faces of the subjects’ own species, the backs of the head of the subjects’ own species, faces of the subjects’ closely related species or race, and faces of species that are clearly different from the subjects’ own species were used as the target. Both the macaques and humans detected a face of their own species more efficiently than a face from a clearly different species. Similar efficient detections were confirmed for the faces of the subjects’ closely related species or race. These results suggest that conspecific faces and faces that share morphological similarity with conspecific faces can be detected efficiently among non-face objects by both humans and Japanese macaques. In another experiment, facial recognition efficiency was observed when the subjects searched for own-species faces that had lower-spatial-frequency components compared to faces with higher-spatial-frequency components. It seems reasonable that the ability to search efficiently for faces by using holistic face processing is derived from fundamental social cognition abilities that are broadly shared among species.     

The contribution of shape and surface information in the other-race face effect

Faces from another race are generally more difficult to recognize than faces from one's own race. However, faces provide multiple cues for recognition and it remains unknown what are the relative contribution of these cues to this “other-race effect”. In the current study, we used three-dimensional laser-scanned head models which allowed us to independently manipulate two prominent cues for face recognition: the facial shape morphology and the facial surface properties (texture and colour). In Experiment 1, Asian and Caucasian participants implicitly learned a set of Asian and Caucasian faces that had both shape and surface cues to facial identity. Their recognition of these encoded faces was then tested in an old/new recognition task. For these face stimuli, we found a robust other-race effect: Both groups were more accurate at recognizing own-race than other-race faces. Having established the other-race effect, in Experiment 2 we provided only shape cues for recognition and in Experiment 3 we provided only surface cues for recognition. Caucasian participants continued to show the other-race effect when only shape information was available, whereas Asian participants showed no effect. When only surface information was available, there was a weak pattern for the other-race effect in Asians. Performance was poor in this latter experiment, so this pattern needs to be interpreted with caution. Overall, these findings suggest that Asian and Caucasian participants rely differently on shape and surface cues to recognize own-race faces, and that they continue to use the same cues for other-race faces, which may be suboptimal for these faces.     

Hypervigilance to rejecting stimuli in rejection sensitive individuals: Behavioral and neurocognitive evidence

Individuals who are high in rejection sensitivity are vigilant toward social cues that signal rejection, and they exhibit attention biases towards information that confirms expectations of rejection. Little is known, however, about the neural correlates of rejection sensitivity. The present study examined whether rejection sensitivity is associated with individuals’ neural responses to rejection-relevant information. Female participants, classified as high or average in rejection sensitivity, completed a modified dot-probe task in which a neutral face was paired with either another neutral face or a gaze-averted (“rejecting”) face while EEG was collected and ERP components were computed. Behavioral results indicated that average rejection sensitive participants showed an attention bias away from rejecting faces, while high rejection sensitive participants were equally vigilant to neutral and rejecting faces. High rejection sensitivity was associated with ERP components signaling elevated attention and arousal to faces. These findings suggest that rejection sensitivity shapes behavioral and neurocognitive responses to faces.     

Latencies to name one of three stimulus dimensions: A study of probability effects and dimension integrality

Following each of 400 stimuli that varied according to three binary dimensions (location, color, and shape), subjects named the value of one particular dimension as quickly as possible. Each stimulus appeared on the “left” and “right” side of a screen (location dimension), and was a “red” or “green” triangle (color dimension) with apex oriented “up” or “down” (shape dimension). The alternatives of each dimension varied according to different probability distributions (90/10, 70/30, or 50/50), and three schedule conditions were contrived so that each distribution occurred once for each dimension. Nine groups of 10 subjects each defined the factorial of 3 (response conditions: identify location, color, or shape) by 3 (schedule conditions: 90 left/70 red/50 down, 70 left/50 red/90 down, or 50 left/90 red/70 down). Latencies to identify the shape dimension were influenced reliably by the probabilities of both response-relevant and response-irrelevant stimuli. Shape probabilities did not affect latencies to identify location of color, but these latencies were significantly influenced by both color and location probabilities. Results are discussed with reference to the locus of the stimulus probability effect and dimensional integrality.     

Predicting face similarity judgements with a computational model of face space

Current models of face representation involve the notion of a high-dimensional face space. Computational models of face space based on principal components analysis (PCA) have been successfully used to predict human judgements of face sex or race. In this work the capability of PCA-based face spaces to predict human judgements of face similarity is examined. Three different paradigms were used. In Experiment 1 subjects learned face-name associations for 18 faces and identified these faces on tachistoscopic presentation. The number of confusions was used as a measure of face similarity. In Experiment 2 the same subjects subjectively rated the similarity of all 153 possible face pairs. In Experiment 3 reaction time to identify a face in an odd-man-out task was measured as an index of face similarity. These empirical measures were correlated with distance of the faces in PCA-based spaces of different dimensionalities. For Experiments 1 and 2 these correlations were highest for one-or two-dimensional face spaces (r=−0.27 vs. −0.28). For Experiment 3 the correlation was highest for a space consisting of 13 dimensions (r=−0.51). Thus PCA-based spaces seem capable to predict human similarity judgements to some extent. Possible reasons for the differences in predictability between paradigms are discussed.     

The influence of facial characteristics on children's age perceptions

To examine the impact of age-related variations in facial characteristics on children's age judgments, two experiments were conducted in which craniofacial shape and facial wrinkling were independently manipulated in stimulus faces as sources of age information. Using a paired-comparisons task, children between the ages of 2 1/2 and 6 were asked to make age category as well as relative age judgments of stimulus faces. Preschool-aged children were able to use variations in craniofacial profile shape, frontal face feature vertical placement, or facial wrinkling to identify the age category of a stimulus person. Children were also able to identify the older, but not the younger, of two faces on the basis of facial wrinkling, a finding consistent with previously demonstrated limitations in young children's use of relative age terms. The results were discussed in the context of research which reveals parallel effects of craniofacial shape and wrinkling on the age judgments of adults.     

眼睛区域构型信息与特征信息的跨维共变增益效应及其加工特异性

面孔知觉可能在区域尺度上发生多维信息整合, 但迄今无特异性实验证据。本研究在两个实验中操纵面孔眼睛区域或嘴巴区域的单维构型或特征信息, 测量人们觉察单维变化或跨维共变的敏感度, 以此检测面孔区域尺度上的多维信息整合有何现象与规律, 进而揭示面孔知觉的多维信息整合机制。实验获得3个发现：(1)正立面孔眼睛区域的信息变化觉察呈现出“跨维共变增益效应”, 跨维信息共变觉察的敏感度显著高于任意一种单维信息变化觉察的敏感度; (2)“跨维共变增益效应”只在正立面孔的眼睛区域出现, 在倒置面孔的眼睛区域、正立面孔的嘴巴区域或倒置面孔的嘴巴区域都没有出现, 因此具有面孔区域特异性和面孔朝向特异性; (3)就单维信息变化觉察而言, 眼睛区域的敏感度不会受到面孔倒置的损伤, 但是嘴巴区域的敏感度会受到面孔倒置的显著损伤。综合可知, 面孔知觉确实会发生区域尺度上的信息整合, 它不是普遍性的信息量效应, 而是特异性的眼睛效应(只发生在正立面孔的眼睛区域)。这是面孔整体加工(face holistic processing)在单维信息分辨和多维信息整合之间建立联系的必经环节。这提示我们对全脸多维信息知觉整合的理解需要从传统的面孔整体加工假设升级到以眼睛为中心的层级化多维信息整合算法(a hierarchical algorithm for multi-dimensional information integration)。     

基于儒家文化的“帝王相”之民间意象的首次探索

本研究通过评价不同性别二态线索和吸引力的面孔图片来考察儒家文化下人们心中帝王面孔形象。采用FaceGen Modeller 3.1操作面孔性别二态线索,并通过PhotoShop CS5合成面孔材料。研究发现:被试认为女性化的男性面孔比男性化的男性面孔更具"帝王相";低吸引力的女性化男性面孔比高吸引力的女性化男性面孔更具"帝王相";不同性别被试之间的评价无显著差异。上述结果显示,在儒家文化影响下,人们偏好具有女性化面孔特点的帝王。     

The face of an angel: Effect of exposure to details of moral behavior on facial recognition memory

The Dangerous Decisions Theory (DDT; Porter & ten Brinke, 2009) posits that instantaneous perceptions of trustworthiness based on a stranger's face influence the manner in which ensuing information about the target is processed. This study tested a bi-directional DDT model, proposing that information concerning a target's moral behavior could distort eyewitness memory for the individual's facial trustworthiness. Participants (N = 141) viewed a target individual's face (previously rated as appearing “neutral” on trustworthiness) and then were exposed to one of the three vignettes describing the target's behavior (either immoral, morally neutral, or altruistic). Following a delay, observers were asked to identify the target individual on a facial morph video (continuously ranging in levels of perceived trustworthiness). Results indicated that behavioral information varying in morality influenced facial recognition memory; specifically, faces were recalled as having less trustworthy features following a disclosure of immoral/criminal behavior.     

Attentional inhibition has social-emotional consequences for unfamiliar faces

Visual attention studies often rely on response time measures to show the impact of attentional facilitation and inhibition. Here we extend the investigation of the effects of attention on behavior and show that prior attentional states associated with unfamiliar faces can influence subsequent social-emotional judgments about those faces. Participants were shown pairs of face images and were asked to withhold a response if a transparent stop-signal cue appeared over one of the faces. This served to associate the cued face with an inhibitory state. Later, when asked to make social-emotional choices about these face pairs, participants chose uncued faces more often than cued faces as "more trustworthy" and chose cued faces more often than uncued faces as "less trustworthy." For perceptual choices, there was no effect of how the question was framed (which face is "on a lighter background" vs. "on a darker background"). These results suggest that attentional inhibition can be associated with socially relevant stimuli, such as faces, and can have specific, deleterious effects on social-emotional judgments.