The Role of the Face and Body in Unfamiliar Person Identification

Information useful for identifying a person can be found both in the face and body. Previous studies indicate that when an entire person is visible, we rely strongly on the face for identification, even if the body can be useful. We measured the utility of the face versus body for identification, by using images of unfamiliar people that varied in the quality of identity information in the face. Face quality was varied using similarity scores generated by state‐of‐the‐art face recognition algorithms from an international competition. These algorithms estimated the similarity of faces in a large set (>1 000 000) of image pairs that showed ‘people’, including the face and the top half of the body. By using these similarity scores, image pairs were stratified into three groups representing good, moderate, and poor performance for the face recognition algorithm. Participants matched identity in image pairs sampled from the three groups, by using versions of the stimuli edited digitally to show only the face or body. Consistent with the algorithm stratifications, performance with the face declined across the three conditions. The face supported more accurate identification than the body in the good and moderate conditions. In the poor condition, performance from the face and body was comparable. Using data from a previous study, we compared the face‐only and body‐only identity judgments with judgments based on the original image. The original unedited image supported the best overall performance in the good and moderate conditions. Notably, performance in the poor condition was equivalent for the face, body, and original images. The results indicate that in poor viewing conditions, identification decisions from the body may be as accurate as those made from the face or the entire person. Copyright © 2013 John Wiley & Sons, Ltd.     

Facial Wipes don't Wash: Facial Image Comparison by Video Superimposition Reduces the Accuracy of Face Matching Decisions

In cases of disputed CCTV identification, expert testimony based on the results of analysis by facial image comparison may be presented to the Jury. However, many of the techniques lack empirical data to support their use. Using a within‐participants design, we compared the accuracy of face‐matching decisions when images were presented using a ‘facial wipe’ technique (where one image is superimposed on another and the display gradually ‘wipes’ between the two) with decisions based on static images. Experiment 1 used high‐quality image pairs; Experiment 2 used disguised target images; and Experiment 3 used degraded target images. Across all three experiments, rather than optimising performance, facial wipes reduced accuracy relative to static presentations. Further, there is evidence that video wipes increase false positives and therefore may increase the likelihood that images of two different people will be incorrectly judged to show the same individual.Copyright © 2016 John Wiley & Sons, Ltd.     

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。     

Performance of typical and superior face recognizers on a novel interactive face matching procedure

Unfamiliar simultaneous face matching is error prone. Reducing incorrect identification decisions will positively benefit forensic and security contexts. The absence of view-independent information in static images likely contributes to the difficulty of unfamiliar face matching. We tested whether a novel interactive viewing procedure that provides the user with 3D structural information as they rotate a facial image to different orientations would improve face matching accuracy. We tested the performance of ‘typical’ (Experiment 1) and ‘superior’ (Experiment 2) face recognizers, comparing their performance using high-quality (Experiment 3) and pixelated (Experiment 4) Facebook profile images. In each trial, participants responded whether two images featured the same person with one of these images being either a static face, a video providing orientation information, or an interactive image. Taken together, the results show that fluid orientation information and interactivity prompt shifts in criterion and support matching performance. Because typical and superior face recognizers both benefited from the structural information provided by the novel viewing procedures, our results point to qualitatively similar reliance on pictorial encoding in these groups. This also suggests that interactive viewing tools can be valuable in assisting face matching in high-performing practitioner groups.     

Ensemble coding of facial identity is not refined by experience: Evidence from other-race and inverted faces

The ability to recognize identity despite within-person variability in appearance is likely a face-specific skill and shaped by experience. Ensemble coding – the automatic extraction of the average of a stimulus array – has been proposed as a mechanism underlying face learning (allowing one to recognize novel instances of a newly learned face). We investigated whether ensemble encoding, like face learning and recognition, is refined by experience by testing participants with upright own-race faces and two categories of faces with which they lacked experience: other-race faces (Experiment 1) and inverted faces (Experiment 2). Participants viewed four images of an unfamiliar identity and then were asked whether a test image of that same identity had been in the study array. Each test image was a matching exemplar (from the array), matching average (the average of the images in the array), non-matching exemplar (a novel image of the same identity), or non-matching average (an average of four different images of the same identity). Adults showed comparable ensemble coding for all three categories (i.e., reported that matching averages had been present more than non-matching averages), providing evidence that this early stage of face learning is not shaped by face-specific experience.     

Wisdom of the social versus non-social crowd in face identification

Face identification is more accurate when people collaborate in social dyads than when they work alone (Dowsett & Burton, 2015, Br. J. Psychol., 106, 433). Identification accuracy is also increased when the responses of two people are averaged for each item to create a ‘non-social’ dyad (White, Burton, Kemp, & Jenkins, 2013, Appl. Cogn. Psychol., 27, 769; White et al., 2015, Proc. R. Soc. B Biol. Sci., 282, 20151292). Does social collaboration add to the benefits of response averaging for face identification? We compared individuals, social dyads, and non-social dyads on an unfamiliar face identity-matching test. We also simulated non-social collaborations for larger groups of people. Individuals and social dyads judged whether face image pairs depicted the same- or different identities, responding on a 5-point certainty scale. Non-social dyads were constructed by averaging the responses of paired individuals. Both social and non-social dyads were more accurate than individuals. There was no advantage for social over non-social dyads. For larger non-social groups, performance peaked at near perfection with a crowd size of eight participants. We tested three computational models of social collaboration and found that social dyad performance was predicted by the decision of the more accurate partner. We conclude that social interaction does not bolster accuracy for unfamiliar face identity matching in dyads beyond what can be achieved by averaging judgements.     

CCTV on trial: Matching video images with the defendant in the dock

The experiments reported in this paper investigated simultaneous identity matching of unfamiliar people physically present in person with moving video images typical of that captured by closed circuit television (CCTV). This simulates the decision faced by a jury in court when the identity of somebody caught on CCTV is disputed. Namely, ‘is the defendant in the dock the person depicted in video’? In Experiment 1, the videos depicted medium‐range views of a number of actor ‘culprits’. Experiment 2 used similar quality images taken a year previously, some of which showed the culprits in disguise. Experiment 3 utilised high‐quality close‐up video images. It was consistently found that in both culprit‐present and culprit‐absent videos and in optimal conditions, matching the identity of a person in video can be highly susceptible to error. Copyright © 2008 John Wiley & Sons, Ltd.     

Using visual codes for comparisons of pictures

In two experiments, Ss indicated for a series of trials whether or not two pictures of common objects had the same name (a positive or negative response, respectively). The pictures were separated by one of three interstimulus intervals (ISis), and reaction time (RT) was recorded. In Experiment I, positive trials involved pictures that were identical (identity match), mirror images (mirror match), or physically different but had the same name (name match). The stimuli came from either an S set, in which name-match pairs were physically similar, or a D set, in which name-match pairs were physically dissimilar. The mean RTs for mirror and identity matches were virtually the same but faster than name-match RTs, an advantage that decreased with increasing ISI. It was expected that name-match RT for the S set would be less than for the D set, indicating a facilitative effect of physical similarity; however, the identity-match RTs showed the expected difference. These results were extended in Experiment II, which involved only the identity and name matches, in pure sessions (which included positive trials of just one type) or mixed sessions (which included both types of positive trials). For mixed sessions, name- as well as identity-match RTs differed between the S and D sets. These results provide evidence for the use of visual codes in comparing nonidentical pictures, codes that apparently vary with experimental context and task demands.     

Smiles in face matching: Idiosyncratic information revealed through a smile improves unfamiliar face matching performance

Unfamiliar face matching is a surprisingly difficult task, yet we often rely on people's matching decisions in applied settings (e.g., border control). Most attempts to improve accuracy (including training and image manipulation) have had very limited success. In a series of studies, we demonstrate that using smiling rather than neutral pairs of images brings about significant improvements in face matching accuracy. This is true for both match and mismatch trials, implying that the information provided through a smile helps us detect images of the same identity as well as distinguishing between images of different identities. Study 1 compares matching performance when images in the face pair display either an open-mouth smile or a neutral expression. In Study 2, we add an intermediate level, closed-mouth smile, to identify the effect of teeth being exposed, and Study 3 explores face matching accuracy when only information about the lower part of the face is available. Results demonstrate that an open-mouth smile changes the face in an idiosyncratic way which aids face matching decisions. Such findings have practical implications for matching in the applied context where we typically use neutral images to represent ourselves in official documents.     

Matching familiar and unfamiliar faces on identity and expression

Summary Subjects were asked to decide whether or not simultaneously presented photographs of pairs of faces were pictures of the same person or of different people (identity matching), or to decide whether or not the pairs of face showed the same expressions or different expressions (expression matching). Faces of familiar and unfamiliar people were used as stimuli. For identity matching, reaction times to familiar faces were faster than reaction times to unfamiliar faces, but there was no difference between familiar and unfamiliar faces for expression matching. These results support the view derived from neuropsychological and neurophysiological studies that analyses of facial expressions proceed independently from processes involved in establishing the person's identity.This research was supported by the ESRC (Grant C 0023 2075)     

Image-size disparity reduces difference detection in face matching

Face matching is the act of deciding whether two facial images depict the same person or different people. The real-world face-matching task of checking photo IDs typically occurs under conditions of image-size disparity: A small picture is compared with a life-size face. We examined the effect of image-size disparity on face-matching accuracy. In three experiments, subjects were presented with pairs of equivalently or disparately sized images that depicted the same person or different people. Subjects made same/different judgments and, in two experiments, also reported confidence. Difference detection was significantly poorer given disparate (versus equivalent) image size. Confidence was significantly higher when responses were correct versus incorrect. These findings held whether viewing and decision time was unlimited or limited. Our results raise the practical concern that image-size disparity may undermine difference detection in ID checking, while also indicating that people have some insight into the accuracy of their face-matching judgments.     

背景性质对7-10岁自闭症谱系障碍儿童面孔搜索与加工的作用

为了考察背景性质对ASD者搜索面孔的影响,设计两个眼动实验任务,要求14名7~10岁ASD儿童和20名同年龄正常儿童观看图片。实验一采用将面孔嵌入风景图片中引起语义不一致的刺激;实验二采用含有面孔的无意义背景乱序图片刺激。结果发现：（1）面孔与背景语义不一致并不能促进ASD儿童对面孔的搜索;（2）乱序背景对ASD儿童面孔搜索与加工没有产生干扰作用,但使正常儿童的搜索时间变长;（3）一旦觉察到面孔后,ASD儿童对面孔的注视时间少于正常儿童。表明正常儿童对面孔的搜索与加工受背景性质的影响,而ASD儿童不受背景性质的影响;一旦发现面孔,ASD儿童的注意维持较短,但面孔加工模式与正常儿童相似。     

When the face fits: Recognition of celebrities from matching and mismatching faces and voices

The results of two experiments are presented in which participants engaged in a face-recognition or a voice-recognition task. The stimuli were face–voice pairs in which the face and voice were co-presented and were either “matched” (same person), “related” (two highly associated people), or “mismatched” (two unrelated people). Analysis in both experiments confirmed that accuracy and confidence in face recognition was consistently high regardless of the identity of the accompanying voice. However accuracy of voice recognition was increasingly affected as the relationship between voice and accompanying face declined. Moreover, when considering self-reported confidence in voice recognition, confidence remained high for correct responses despite the proportion of these responses declining across conditions. These results converged with existing evidence indicating the vulnerability of voice recognition as a relatively weak signaller of identity, and results are discussed in the context of a person-recognition framework.     

What happens to our representation of identity as familiar faces age? Evidence from priming and identity aftereffects

Matching identity in images of unfamiliar faces is error prone, but we can easily recognize highly variable images of familiar faces – even images taken decades apart. Recent theoretical development based on computational modelling can account for how we recognize extremely variable instances of the same identity. We provide complementary behavioural data by examining older adults’ representation of older celebrities who were also famous when young. In Experiment 1, participants completed a long-lag repetition priming task in which primes and test stimuli were the same age or different ages. In Experiment 2, participants completed an identity after effects task in which the adapting stimulus was an older or young photograph of one celebrity and the test stimulus was a morph between the adapting identity and a different celebrity; the adapting stimulus was the same age as the test stimulus on some trials (e.g., both old) or a different age (e.g., adapter young, test stimulus old). The magnitude of priming and identity after effects were not influenced by whether the prime and adapting stimulus were the same age or different age as the test face. Collectively, our findings suggest that humans have one common mental representation for a familiar face (e.g., Paul McCartney) that incorporates visual changes across decades, rather than multiple age-specific representations. These findings make novel predictions for state-of-the-art algorithms (e.g., Deep Convolutional Neural Networks).     

Being ‘Spiritual’ and Being ‘Religious’ in Europe: Diverging Life Orientations

The present study shows that being ‘spiritual’ and being ‘religious’ are becoming different life orientations for a large part of the population. As far as we know, for the first time, a sample from an European country shows that these orientations are reflected in two coherent clusters of beliefs, experiences, and practices of what we call ‘new spirituality’ on the one hand and ‘traditional, church-related religion’ on the other hand. In addition, it appears that ‘only spiritual’ (and not ‘religious’) people and ‘only religious’ (and not ‘spiritual’) people have less ‘intensive’ spiritual/religious lives than people who describe themselves as ‘both spiritual and religious’. The ‘both’ category is not homogenous, probably as a result of the different associations which its members have of the conceptions of ‘spiritual’ and ‘religious’. The people in this category can be sub-divided in two sub-groups which show different profiles.     

What’s in a name? Lexical knowledge drives infants’ visual preferences in the absence of referential input

Seventeen-month-old infants were presented with pairs of images, in silence or with the non-directive auditory stimulus ‘look!’. The images had been chosen so that one image depicted an item whose name was known to the infant, and the other image depicted an image whose name was not known to the infant. Infants looked longer at images for which they had names than at images for which they did not have names, despite the absence of any referential input. The experiment controlled for the familiarity of the objects depicted: in each trial, image pairs presented to infants had previously been judged by caregivers to be of roughly equal familiarity. From a theoretical perspective, the results indicate that objects with names are of intrinsic interest to the infant. The possible causal direction for this linkage is discussed and it is concluded that the results are consistent with Whorfian linguistic determinism, although other construals are possible. From a methodological perspective, the results have implications for the use of preferential looking as an index of early word comprehension.     

How many voices did you hear? Natural variability disrupts identity perception from unfamiliar voices

Our voices sound different depending on the context (laughing vs. talking to a child vs. giving a speech), making within‐person variability an inherent feature of human voices. When perceiving speaker identities, listeners therefore need to not only ‘tell people apart’ (perceiving exemplars from two different speakers as separate identities) but also ‘tell people together’ (perceiving different exemplars from the same speaker as a single identity). In the current study, we investigated how such natural within‐person variability affects voice identity perception. Using voices from a popular TV show, listeners, who were either familiar or unfamiliar with this show, sorted naturally varying voice clips from two speakers into clusters to represent perceived identities. Across three independent participant samples, unfamiliar listeners perceived more identities than familiar listeners and frequently mistook exemplars from the same speaker to be different identities. These findings point towards a selective failure in ‘telling people together’. Our study highlights within‐person variability as a key feature of voices that has striking effects on (unfamiliar) voice identity perception. Our findings not only open up a new line of enquiry in the field of voice perception but also call for a re‐evaluation of theoretical models to account for natural variability during identity perception.     

The effects of spatial frequency overlap on face recognition

The effects of spatial frequency overlap between pairs of low-pass versus high-pass images on face recognition and matching were examined in 6 experiments. Overlap was defined as the range of spatial frequencies shared by a pair of filtered images. This factor was manipulated by processing image pairs with high-pass/low-pass filter pairs whose 50% cutoff points varied in their separation from one another. The effects of the center frequency of filter pairs were also investigated. In general, performance improved with greater overlap and higher center frequency. In control conditions, the image pairs were processed with identical filters and thus had complete overlap. Even severely filtered low-pass or high-pass images in these conditions produced superior performance. These results suggest that face recognition is more strongly affected by spatial frequency overlap than by the frequency content of the images.     

What’s the object of object working memory in infancy? Unraveling ‘what’ and ‘how many’

Infants have a bandwidth-limited object working memory (WM) that can both individuate and identify objects in a scene, (answering ‘how many?’ or ‘what?’, respectively). Studies of infants’ WM for objects have typically looked for limits on either ‘how many’ or ‘what’, yielding different estimates of infant capacity. Infants can keep track of about three individuals (regardless of identity), but appear to be much more limited in the number of specific identities they can recall. Why are the limits on ‘how many’ and ‘what’ different? Are the limits entirely separate, do they interact, or are they simply two different aspects of the same underlying limit?We sought to unravel these limits in a series of experiments which tested 9- and 12-month-olds’ WM for object identities under varying degrees of difficulty. In a violation-of-expectation looking-time task, we hid objects one at a time behind separate screens, and then probed infants’ WM for the shape identity of the penultimate object in the sequence. We manipulated the difficulty of the task by varying both the number of objects in hiding locations and the number of means by which infants could detect a shape change to the probed object. We found that 9-month-olds’ WM for identities was limited by the number of hiding locations: when the probed object was one of two objects hidden (one in each of two locations), 9-month-olds succeeded, and they did so even though they were given only one means to detect the change. However, when the probed object was one of three objects hidden (one in each of three locations), they failed, even when they were given two means to detect the shape change. Twelve-month-olds, by contrast, succeeded at the most difficult task level.Results show that WM for ‘how many’ and for ‘what’ are not entirely separate. Individuated objects are tracked relatively cheaply. Maintaining bindings between indexed objects and identifying featural information incurs a greater attentional/memory cost. This cost reduces with development. We conclude that infant WM supports a small number of featureless object representations that index the current locations of objects. These can have featural information bound to them, but only at substantial cost.