The role of eyebrows in face recognition

A fundamental challenge in face recognition lies in determining which facial characteristics are important in the identification of faces. Several studies have indicated the significance of certain facial features in this regard, particularly internal ones such as the eyes and mouth. Surprisingly, however, one rather prominent facial feature has received little attention in this domain: the eyebrows. Past work has examined the role of eyebrows in emotional expression and nonverbal communication, as well as in facial aesthetics and sexual dimorphism. However, it has not been made clear whether the eyebrows play an important role in the identification of faces. Here, we report experimental results which suggest that for face recognition the eyebrows may be at least as influential as the eyes. Specifically, we find that the absence of eyebrows in familiar faces leads to a very large and significant disruption in recognition performance. In fact, a significantly greater decrement in face recognition is observed in the absence of eyebrows than in the absence of eyes. These results may have important implications for our understanding of the mechanisms of face recognition in humans as well as for the development of artificial face-recognition systems.     

The role of rigid motion in newborns' face recognition

The study investigated whether dynamic information promotes newborns' ability to recognize a face. After being habituated to a face undergoing an ordered sequential head rigid motion (Exp. 1), 1- to 3-day-old newborns fully recognized the familiar face shown in the profile pose, as documented by a preference for the profile pose of a novel face. When familiarized to an ordered sequence of different viewpoint static images of a face (Exp. 2), newborns failed to recognize the profile pose of the familiar face, their visual exploration of the familiar and novel faces being at chance. Habituation to a random head rigid motion (Exp. 3) allowed only a partial recognition of face identity, as newborns preferred the profile pose of the familiar, rather than the novel, face. Rigid head motion is an important source of information for newborns' face recognition, probably aiding the derivation of a three-dimensional face structure.     

The role of motion and speech in face recognition at birth

Newborns, a few hours after birth, already encounter many different faces, talking or silently moving. How do they process these faces and which cues are important in early face recognition? In a series of six experiments, newborns were familiarized with an unfamiliar face in different contexts (photographs, talking, silently moving, and with only external movements of the head with speech sound). At test, they saw the familiar and a new faces either in photographs, silently moving, or talking. A novelty preference was evidenced at test when photographs were presented in the two phases. This result supports those already evidenced in several studies. A familiarity preference appeared only when the face was seen talking in the familiarization phase and in a photograph or talking again at test. This suggests that the simultaneous presence of speech sound, and rigid and nonrigid movements present in a talking face enhances recognition of interactive faces at birth.     

The role of higher level adaptive coding mechanisms in the development of face recognition

Developmental improvements in face identity recognition ability are widely documented, but the source of children’s immaturity in face recognition remains unclear. Differences in the way in which children and adults visually represent faces might underlie immaturities in face recognition. Recent evidence of a face identity aftereffect (FIAE), in which adaptation (exposure) to a particular identity causes a previously neutral face to take on the computationally opposite identity, suggests that adults code faces in an opponent fashion relative to an average face. One previous study showed comparable FIAEs in 8-year-olds and adults but did not demonstrate that adaptation was selective for high-level representations in both groups. Using a developmentally appropriate FIAE task, we investigated whether children show adult-like adaptation for facial identity when adapting and test images differ in size. Both age groups showed an equivalent FIAE, suggesting that qualitative changes in the use of higher level adaptive coding mechanisms do not drive the developmental improvements in face recognition ability, at least from 8 years of age.     

Emotion recognition: The role of featural and configural face information

Several studies investigated the role of featural and configural information when processing facial identity. A lot less is known about their contribution to emotion recognition. In this study, we addressed this issue by inducing either a featural or a configural processing strategy (Experiment 1) and by investigating the attentional strategies in response to emotional expressions (Experiment 2). In Experiment 1, participants identified emotional expressions in faces that were presented in three different versions (intact, blurred, and scrambled) and in two orientations (upright and inverted). Blurred faces contain mainly configural information, and scrambled faces contain mainly featural information. Inversion is known to selectively hinder configural processing. Analyses of the discriminability measure (A′) and response times (RTs) revealed that configural processing plays a more prominent role in expression recognition than featural processing, but their relative contribution varies depending on the emotion. In Experiment 2, we qualified these differences between emotions by investigating the relative importance of specific features by means of eye movements. Participants had to match intact expressions with the emotional cues that preceded the stimulus. The analysis of eye movements confirmed that the recognition of different emotions rely on different types of information. While the mouth is important for the detection of happiness and fear, the eyes are more relevant for anger, fear, and sadness.     

The perception of face gender: The role of stimulus structure in recognition and classification

The perception of face gender was examined in the context of extending “face space” models of human face representations to include the perceptual categories defined by male and female faces. We collected data on the recognizability, gender classifiability (reaction time to classify a face as male/female), attractiveness, and masculinity/femininity of individual male and female faces. Factor analyses applied separately to the data for male and female faces yielded the following results. First, for both male and female faces, the recognizability and gender classifiability of faces were independent—a result inconsistent with the hypothesis that both recognizability and gender classifiability depend on a face’s “distance” from the subcategory gender prototype. Instead, caricatured aspects of gender (femininity/masculinity ratings) related to the gender classifiability of the faces. Second, facial attractiveness related inversely to face recognizability for male, but not for female, faces—a result that resolves inconsistencies in previous studies. Third, attractiveness and femininity for female faces were nearly equivalent, but attractiveness and masculinity for male faces were not equivalent. Finally, we applied principal component analysis to the pixel-coded face images with the aim of extracting measures related to the gender classifiability and recognizability of individual faces. We incorporated these model-derived measures into the factor analysis with the human rating and performance measures.     

Children's face recognition in different contexts: the role of encoding strategies

In this study, the relationship between face recognition and different facial encoding strategies was investigated. Children (6-8 years, N= 134) participated in both a face recognition task and an encoding task. During the recognition task, they saw 7 target faces in an eyewitness context (video) or in a neutral context (static black and white slides) which they later had to recognize from a set of 21 faces. On the encoding task, the same children had to categorize new faces (schematic and photorealistic) into two categories. The construction of the categories allowed participants to encode the faces either analytically (by focusing on a single attribute) or holistically (in terms of overall similarity). The results showed that face recognition was better in the social than in the neutral context. In the neutral context, only holistic encoding was connected to better face recognition. In the social context, children seemed to use not only information about the faces but also information about the persons.     

Moderators of the confidence-accuracy correlation in face recognition: The role of information processing and base-rates

Forty-four undergraduates were shown one set of slides of persons in the beginning of the session and a second set of slides at the end. During the second slide presentation subjects gave recognition judgements for each slide and confidence judgements for each decision. The disguise of the to-be-recognized (TBR) persons was varied and the distinctiveness and attractiveness of the TBR persons were assessed. The relation between subjects' confidence judgements and their face recognition accuracy was stronger if the TBR persons were not disguised and if the TBR persons had distinctive characteristics. Attractiveness was unrelated to face recognition accuracy. Base-rate information, which referred to the number of persons the subjects expected to recognize, affected decision criterion but had no effect on confidence judgements.     

When inverted faces are recognized: The role of configural information in face recognition

The identification of upright faces seems to involve a special sensitivity to "configural" information, the processing of which is less effective when the face is inverted. However the precise meaning of "configural" remains unclear. Five experiments are presented, which showed that the disruption of the processing of relational, rather than holistic, information largely determines the occurrence as well as the size of the face-inversion effect. In Experiment 1, faces could be identified either by unique combinations of local information (e.g. a specific eye colour plus hair colour) or by unique relational information (e.g. nose-mouth distance). The former showed no inversion effect, whereas the latter did. A combination of local and relational information (Experiment 2) again produced an inversion effect, although this effect was smaller than that found when only relational information was used. The results were replicated in Experiment 3 when differences in the brightness of local features were used instead of specific colour combinations. Experiment 4 used different retrieval conditions to distinguish relational from holistic processing, and demonstrated again that spatial relations between single features appeared to provide crucial information for face recognition. In Experiment 5, the importance of relational information was confirmed using faces that also varied in the shapes of local features.     

Challenges older adults face in detecting deceit: the role of emotion recognition

Facial expressions of emotion are key cues to deceit (M. G. Frank & P. Ekman, 1997). Given that the literature on aging has shown an age-related decline in decoding emotions, we investigated (a) whether there are age differences in deceit detection and (b) if so, whether they are related to impairments in emotion recognition. Young and older adults (N = 364) were presented with 20 interviews (crime and opinion topics) and asked to decide whether each interview subject was lying or telling the truth. There were 3 presentation conditions: visual, audio, or audiovisual. In older adults, reduced emotion recognition was related to poor deceit detection in the visual condition for crime interviews only.     

Glucose regulation and face recognition deficits in older adults: the role of attention

The present study investigated the perceptual, attentional, and memory processes underlying face recognition deficits observed in older adults with impaired glucoregulation. Participants were categorized as good glucoregulators or poor glucoregulators on the basis of an oral glucose tolerance test. Using event-related potential (ERP) methodology, 23 participants (62–88 years) performed a 2-stimulus oddball task. Participants were asked to rate and memorize 10 “target” faces, which were then presented amongst 120 unfamiliar foils. Behavioral results indicated that good glucoregulators were significantly more accurate at recognizing target faces. ERP markers of early visual perception (P1 and N170 components) and memory formation (P3 component) were unaffected by glucoregulatory efficiency. The P2 component, an index of attentional processing, was larger and delayed in the poor glucoregulators. To the best of our knowledge, this study is the first to suggest that face recognition deficits in poor glucoregulators may be due to impairments in attentional processing.     

熟悉面孔与陌生面孔识别的差异

摘 要：面孔识别包括熟悉面孔识别和陌生面孔识别,两者之间的差异已经得到了多方面的证明。神经生理学的研究发现,识别陌生面孔和熟悉面孔所激活的脑区存在差异,与识别陌生面孔相比,识别熟悉面孔的脑区活动范围更大,包括双侧前额叶、单侧颞叶、海马回、杏仁核、后扣带回和右下额叶。并且也存在脑电的差异,比如 N400和P600的差异。对陌生面孔和熟悉面孔识别具有相同影响的因素有：遮挡、倒置等;具有不同影响的因素有：视角、表情、内外部特征等。文章也探讨了陌生面孔变成熟悉面孔的过程,以及在这一过程中起主要作用的编码形式等。     

The role of letter recognition in word recognition

In a paradigm that avoids methodological problems of earlier studies, evidence was gathered addressed to the question of whether we read letter by letter. If word recognition involves letter recognition, then the difficulty of recognizing a word should vary with the difficulty of recognizing its letters. This was tested by assessing letter difficulty in two letter discrimination tasks and in a letter naming task, and then comparing 15 adult subjects' visual recognition latency to 72 easy-letter words and to 72 difficult-letter words. Word frequency and word length were also manipulated. Results indicated no effect for letter difficulty, although recognition latency reliably decreased with word frequency and monotonically increased with word length (21 msec/letter), suggesting that we do not read letter by letter, but that whatever plays a role in word recognition is smaller than the word and correlated with word length in letters.     

The effects of delay and exposure duration in a face recognition task

Face recognition was investigated in a successive comparison task. Subjects were required to makesame/different judgments about pairs of Photo-fit faces that were either identical or differed by a single feature. Picture information extraction and retention were examined by manipulating stimulus delay and exposure duration. Results indicated that overall performance was better for the top of the face. The eyes and mouth were more vulnerable than the rest of the face to recognition decrement after a delay, possibly due to their role in facial expression. When features were ranked in order of processing difficulty for each subject, it appeared that features were processed serially and delay affected a retrieval stage, while short exposure affected a visual comparison stage of processing. For the feature ranks, a single dimension of “salience” appeared to be both perceptual and mnemonic.     

Gender is a dimension of face recognition

In an experiment, the authors investigated the impact of gender categorization on face recognition. Participants were familiarized with composite androgynous faces labeled with either a woman's first name (Mary) or a man's first name (John). The results indicated that participants more quickly eliminated faces of the opposite gender than faces of the same gender than the face they were looking for. This gender effect did not result from greater similarity between faces of the same gender. Rather, early gender categorization of a face during face recognition appears to speed up the comparison process between the perceptual input and the facial representation. Implications for face recognition models are discussed.     

The neural plasticity of other-race face recognition

Although it is well established that people are better at recognizing own-race faces than at recognizing other-race faces, the neural mechanisms mediating this advantage are not well understood. In this study, Caucasian participants were trained to differentiate African American (or Hispanic) faces at the individual level (e.g., Joe, Bob) and to categorize Hispanic (or African American) faces at the basic level of race (e.g., Hispanic, African American). Behaviorally, subordinate-level individuation training led to improved performance on a posttraining recognition test, relative to basic-level training. As measured by event-related potentials, subordinate- and basic-level training had relatively little effect on the face N170 component. However, as compared with basic-level training, subordinate-level training elicited an increased response in the posterior expert N250 component. These results demonstrate that learning to discriminate other-race faces at the subordinate level of the individual leads to improved recognition and enhanced activation of the expert N250 component.     

The development of spatial frequency biases in face recognition

Previous research has suggested that a mid-band of spatial frequencies is critical to face recognition in adults, but few studies have explored the development of this bias in children. We present a paradigm adapted from the adult literature to test spatial frequency biases throughout development. Faces were presented on a screen with particular spatial frequencies blocked out by noise masks. A mid-band bias was found in adults and 9- and 10-year-olds for upright faces but not for inverted faces, suggesting a face-sensitive effect. However, 7- and 8-year-olds did not demonstrate the mid-band bias for upright faces but rather processed upright and inverted faces similarly. This suggests that specialization toward the mid-band for upright face recognition develops gradually during childhood and may relate to an advanced level of face expertise.     

The own-age bias in face recognition: a meta-analytic and theoretical review

A large number of studies have examined the finding that recognition memory for faces of one's own age group is often superior to memory for faces of another age group. We examined this own-age bias (OAB) in the meta-analyses reported. These data showed that hits were reliably greater for same-age relative to other-age faces (g = 0.23) and that false alarms were reliably less likely for same-age compared with other-age faces (g = -0.23). Further meta-analyses of measures of signal detection demonstrated that, although no difference in response criterion was evident (g = -0.01), discriminability was reliably better for same-age compared with other-age faces (g = 0.37). As well, children, younger adults, and older adults exhibited superior discriminability for same-age compared with other-age age faces. Thus, the OAB appears to be a robust effect that influences the accuracy of face recognition. Theoretical accounts of the OAB have generally suggested that it reflects more extensive, recent experiences with one's own age group relative to other-age groups. Additional analyses were supportive of this account as the OAB was present even for groups (e.g., older adults) that had prior experiences as members of another age group. However, the most comprehensive account of the OAB will also likely invoke mechanisms suggested by social-cognitive theories.     

Ambiguous emotion recognition in temporal lobe epilepsy: The role of expression intensity

The lateralization of emotion processing is currently debated and may be further explored by examining facial expression recognition (FER) impairments in temporal lobe epilepsy (TLE). Furthermore, there is also debate in the literature whether FER deficits in individuals with TLE are more pronounced in the right than in the left hemisphere. Individuals with TLE were tested with an FER task designed to be more sensitive than those classically used to shed light on this issue. A total of 25 right- and 32 left-TLE patients, candidates for surgery, along with controls, underwent an FER task composed of stimuli shown not only at full-blown intensities (100 %), but also morphed to lower-intensity display levels (35 %, 50 %, and 75 %). The results showed that, as compared to controls, right-TLE patients showed deficits in the recognition of all emotional categories. Furthermore, when considering valence, right-TLE patients were impaired only in negative emotion recognition, but no deficits for positive emotions were highlighted in left-TLE patients. Finally, only the right-TLE patients’ impairment was found to be related to the age of epilepsy onset. Our work demonstrates that the FER deficits in TLE span multiple emotional categories and show manifestations dependent on the laterality of the epileptic focus. Taken together, our findings provide the strongest evidence for the right-hemisphere model, but they also partially support the valence model. We suggest that current models are not exhaustive at explaining emotional-processing cerebral control, and further that multistep models should be developed.