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PubMed2006

Do I know you? Insights into memory for faces from brain potentials.

The recognition of faces is central to human social interaction. Recordings of event-related potentials (ERPs) from the brain can shed light on the various processes that occur when a face is recognized and when knowledge related to a specific person is retrieved. ERP contrasts between processing familiar and processing novel faces offer a gateway into investigations of semantic memory for familiar persons. In particular, activity of face recognition units and semantic information units--memory representations of faces and person-related knowledge, respectively--can be indexed by specific ERPs. These potentials thus provide valuable tools for studying the cognitive and neurobiological architecture of person recognition. ERPs have also been found useful for investigating other types of memory for faces. Specifically, important insights have been derived from the study of a category of memory phenomena known as priming. Priming can be revealed in special tests when face recognition is facilitated based on prior experience. Describing the neural processes associated with memory for faces is an exciting focus of research, and future results from this line of inquiry promise to provide further knowledge about face recognition and the various types of memory that can be provoked by a human face.

Brain↗
PubMed2004

The covert priming effect of faces in prosopagnosia.

BACKGROUND: There are many methods of testing covert face recognition in prosopagnosia, but it is not clear whether different types of covert recognition share a common mechanism. OBJECTIVE: To determine whether direct forced-choice techniques and indirect face-priming methods yielded similar behavioral estimates of covert ability in a series of prosopagnosic patients. METHODS: The authors tested seven control subjects and seven prosopagnosic patients. Six patients had an apperceptive prosopagnosia: one with childhood onset, three with bilateral lesions, and two with unilateral occipitotemporal lesions. The last had an associative prosopagnosia from bilateral anterior temporal lesions. The direct tests of covert function involved sorting faces by occupation or the forced choosing of which of two faces was famous with a name cue. The indirect test assessed name classification by occupation after priming with a facial stimulus. RESULTS: In normal subjects, the chief priming effect was facilitation by the true face. In the six patients with apperceptive prosopagnosia, direct covert measures were correlated with the face-priming effect, with better covert ability in patients with unilateral posterior lesions. In the patient with associative prosopagnosia, there was a dissociation between excellent direct covert function and absent face priming. CONCLUSIONS: Direct and indirect covert functions likely share similar mechanisms in patients with apperceptive prosopagnosia and may reflect residual activity in anterior and left hemispheric components of the normal face-processing network. However, face priming may be ineffectual in patients with severely degraded facial memories from anterior temporal damage. This may indicate a difference between residual patterns of face-related activity in associative and apperceptive prosopagnosia.

Adult↗
PubMed2006

Beneficial effects of verbalization and visual distinctiveness on remembering and knowing faces.

We examined the effect of verbally describing faces upon visual memory. In particular, we examined the locus of the facilitative effects of verbalization by manipulating the visual distinctiveness ofthe to-be-remembered faces and using the remember/know procedure as a measure of recognition performance (i.e., remember vs. know judgments). Participants were exposed to distinctive faces intermixed with typical faces and described (or not, in the control condition) each face following its presentation. Subsequently, the participants discriminated the original faces from distinctive and typical distractors in a yes/no recognition decision and made remember/know judgments. Distinctive faces elicited better discrimination performance than did typical faces. Furthermore, for both typical and distinctive faces, better discrimination performance was obtained in the description than in the control condition. Finally, these effects were evident for both recollection- and familiarity-based recognition decisions. We argue that verbalization and visual distinctiveness independently benefit face recognition, and we discuss these findings in terms of the nature of verbalization and the role of recollective and familiarity-based processes in recognition.

Adolescent↗
PubMed1999

The prototype effect in face recognition: extension and limits.

The prototype effect in face recognition refers to a tendency to recognize the face corresponding to the central value of a series of seen faces, even when this central value or prototype has not been seen. Five experiments investigated the extension and limits of this phenomenon. In all the experiments, participants saw a series of faces, each one in two or more different versions or exemplars, and then performed a recognition test, including seen and unseen exemplars and the unseen prototype face. In Experiment 1, a strong prototype effect for variations in feature location was demonstrated in oldness ratings and in a standard old/new recognition test. Experiments 2A and 2B compared the prototype effect for variations in feature location and variations in head angle and showed that, for the latter, the prototype effect was weaker and more dependent on similarity than for the former. These results suggest that recognition across feature variations is based on an averaging mechanism, whereas recognition across viewpoint variations is based on an approximation mechanism. Experiments 3A and 3B examined the limits of the prototype effect using a face morphing technique that allows a systematic manipulation of face similarity. The results indicated that, as the similarity between face exemplars decreases to the level of similarity between the faces of different individuals, the prototype effect starts to disappear. At the same time, the prototype effect may originate false memories of faces that were never seen.

Adult↗
PubMed2006

The role of attention and familiarity in face identification.

How is attention allocated during face identification? Previous work using famous and unfamiliar faces suggests that either no attention or a special attentional mechanism is required. We used a conventional attentional blink (AB) procedure to measure face identification with temporarily reduced attention. The participants viewed a rapid series of face images with one embedded nonface abstract pattern (T1). They judged the texture of T1 and then detected a prespecified face (T2) presented at varying lags after T1. T2 was either famous or unfamiliar, as were distractor faces. Regardless of distractor type, detection of an unfamiliar T2 face was significantly impaired at short versus long T1-T2 lags, indicating an attentional requirement for face identification. Detection of a famous T2 face was unaffected by lag, suggesting that familiarity protects against atemporal attentional bottleneck These findings do not support propositions that face identification is "special" in its need for attentional control

Adult↗
PubMed1994

Structural aspects of face recognition and the other-race effect.

The other-race effect was examined in a series of experiments and simulations that looked at the relationships among observer ratings of typicality, familiarity, attractiveness, memorability, and the performance variables of d' and criterion. Experiment 1 replicated the other-race effect with our Caucasian and Japanese stimuli for both Caucasian and Asian observers. In Experiment 2, we collected ratings from Caucasian observers on the faces used in the recognition task. A Varimax-rotated principal components analysis on the rating and performance data for the Caucasian faces replicated Vokey and Read's (1992) finding that typicality is composed of two orthogonal components, dissociable via their independent relationships to: (1) attractiveness and familiarity ratings and (2) memorability ratings. For Japanese faces, however, we found that typicality was related only to memorability. Where performance measures were concerned, two additional principal components dominated by criterion and by d' emerged for Caucasian faces. For the Japanese faces, however, the performance measures of d' and criterion merged into a single component that represented a second component of typicality, one orthogonal to the memorability-dominated component. A measure of face representation quality extracted from an autoassociative neural network trained with a majority of Caucasian faces and a minority of Japanese faces was incorporated into the principal components analysis. For both Caucasian and Japanese faces, the neural network measure related both to memorability ratings and to human accuracy measures. Combined, the human data and simulation results indicate that the memorability component of typicality may be related to small, local, distinctive features, whereas the attractiveness/familiarity component may be more related to the global, shape-based properties of the face.

Asian People↗
PubMed1997

Features and their configuration in face recognition.

Tanaka and Farah (1993) have proposed a holistic approach to face recognition in which information about the features of a face and their configuration are combined together in the face representation. An implication of the holistic hypothesis is that alterations in facial configuration should interfere with retrieval of features. In four experiments, the effect of configuration on feature recognition was investigated by creating two configurations of a face, one with eyes close together and one with eyes far apart. After subjects studied faces presented in one of the two configurations (eyes-close or eyes-far), they were tested for their recognition of features shown in isolation, in a new face configuration, and in the old face configuration. It was found that subjects recognized features best when presented in the old configuration, next best in the new configuration, and poorest in isolation. Moreover, subjects were not sensitive to configural information in inverted faces (Experiment 2) or nonface stimuli (i.e., houses; Experiments 3 and 4). Importantly, for normal faces, altering the spatial location of the eyes not only impaired subjects' recognition of the eye features but also impaired their recognition of the nose and mouth features-features whose spatial locations were not directly altered. These findings emphasize the interdependency of featural and configural information in a holistic face representation.

Adult↗
PubMed1994

Upright versus upside-down faces: how interface attractiveness varies with orientation.

A choice experiment is reported in which all pairs and triples of faces from a set of eight moderately attractive faces were presented, both upright and upside down, to 103 subjects. In each orientation, the subjects had to select the face that appeared more (pairs) or most (triples) attractive to them. For each orientation, the preference probabilities that arose from the pair and triple comparisons could be described by the BTL rule (Luce, 1959). Thus, each face was represented by two scores, one reflecting its attractiveness in the upright orientation and the other reflecting its attractiveness in the inverted orientation. Orientation affected the preference probabilities. Qualitatively, score ratios between faces decreased from upright to inverted orientation, suggesting that the faces became less discriminable by inversion. Quantitatively, the effect of inversion could be described by a simple rule that assumes a face's two attractiveness scores to be affinely related across orientations. This result indicates that inversion affected all faces about equally. The present findings are discussed with respect to faces' first- and second-order relational properties, a distinction emphasized in current theories of face perception. They suggest that the processing of first- and second-order relational properties is impaired by inversion to roughly the same degree.

Adult↗
PubMed1992

[Face recognition in preschool children: effects of familiarity, facial expression and angle of view].

The purpose of this study was to investigate the face recognition processes in preschool children. Two experiments were carried out to examine the effects, on face recognition, of familiarity, facial expression and angle of view of faces as well as changes or no changes in facial expression and/or angle of view occurring between the first presentation and the subsequent recognition test. The subjects were 188 five- and six-year old children. In Experiments 1 and 2, half of the faces were highly familiar to the subjects, and the remaining half unfamiliar to them. In Experiment 1, the facial expressions (e.g., smiling or serious) were either changed or unchanged. In Experiment 2, the facial expressions or angles of view (e.g., full-face views or three-quarter views of faces) were either changed or unchanged. The major findings were that the familiar faces and the smiling faces were recognized more correctly than the unfamiliar faces and the serious faces respectively. The results were discussed in terms of 'identity-specific semantic codes' and 'visually-derived semantic codes'.

Child↗
PubMed2000

[Experiences with development of morphological typology of the face].

On base of the component analysis of facial dimensions the original diagnostic model of definition of a morphological facial type in Russian males and females is developed. The first typological characteristic feature describes the variability of general face size, allocating extreme micro- and macrotypes. The second one describes the face shape as a ratio of frontal and mandibular parts. On poles of variability it demonstrates a type with massive frontal face part and rather reduced mandibular one, and a contrast type with a massive mandibular part at relative gracile frontal face part. Central position in this model is occupied by variants with equally proportional development of the top and bottom face parts. On the basis of seven traditional anthropometric facial dimensions the place of any individual in terms of face size and form can be easily found in the suggested model. The chosen contrast variants of the face form are comparable to the appropriate characteristics of cerebral and digestive Sigaud types. The offered morphotypology allows to estimate accurately individual and group features in the face form. The methods of multivariate analysis reveal steady connection between somatotypes and features of a facial structure. Though the level of correlation does not exceed 0.3-0.4 of correlation coefficients, it is statistically significant at the highest degree of probability. The basic direction of habitus variability in men is observed at general face size, in women at face shape.

Adult↗
PubMed2001

Relationship between the face and the tooth form.

The aim of this study was to re-examine Leon Williams geometric theory and to find the degree of correspondence between the face and the tooth form in the population of Zenica, Bosnia and Herzegovina. Two thousand individuals with intact frontal teeth, in age between 17 and 24 years, were measured for 3 horizontal distances on the face: temporal width (Ft-Ft), zygomatic width (Zyg-Zyg) and gonial width (Go-Go) and for 3 horizontal distances on the both upper incisors: cervical width (CW), contact point width (CPW) and incisal width (IW). The length of the face (Tr-Gn) as well as the length of the central maxillary incisors were also measured. The results revealed: 1. Men had significantly larger dimensions for all facial and tooth dimensions (p < 0.05) than women, except for the cervical tooth width (p > 0.05); the left and the right central incisors were of identical dimensions and forms (p > 0.05). 2. The width of upper central incisors were smaller approximately 1.5 mm than in west Europeans. 3. Upon the relation between the 3 horizontal dimensions measured on the face and upper maxillary incisor, 11 facial forms and 10 upper central tooth forms could be recognised in the study population, but 98% of the population had only 3 tooth and face forms. Face shapes: oval face--83.3%, square-tapered face--9.2% and tapered face--7%; tooth forms: tapered-square incisor--53%, oval incisor--30%, tapered incisor--16%. 4. Reversed and enlarged tooth form was in line associated with the facial form in only 30%, while the most common combination was of the oval face form and the tapered-square central incisor (45%). 5. These results disapprove William's theory and may be helpful for the choice of artificial teeth in complete denture construction and the dental industry.

Adolescent↗
PubMed1979

The definition of the face.

There is no generally agreed definition of the human and subhuman face. For primatologists the definition forwarded by PERKNOPF (1957) is most agreeable: all structures of the head which can be seen from en face belong to the human face. The face is a combination of structures heterogeneous in both anatomy and function (forehead, eyes, mouth, pelage, etc.). They are different in qualities (e.g., color of the skin or the hair) and quantities as well (length of the jaw or the hairs of the mane). Despite the heterogeneity in form and function, the face as a whole appears as a unit, because in facial expressions there is always more than one structure involved. Blage, etc.). They are different in qualities (e.g., color of the skin or the hair) and quantities as well (length of the jaw or the hairs of the mane). Despite the heterogeneity in form and function, the face as a whole appears as a unit, because in facial expressions there is always more than one structure involved. Blage, etc.). They are different in qualities (e.g., color of the skin or the hair) and quantities as well (length of the jaw or the hairs of the mane). Despite the heterogeneity in form and function, the face as a whole appears as a unit, because in facial expressions there is always more than one structure involved. Because of the frontally oriented eyes and the stereoscopic vision, the facial structures are situated on the head so that they can be seen from in front. This is the reason why primate display mainly face to face. The concepts of the internal and external face are justified only in terms of topographical anatomy.

Adipose Tissue↗
PubMed2006

Biometric identification using 3D face scans.

Biometrics is an emerging area of bioengineering that pursues the characterization of a person by means of something that the person is or produces. Face recognition is a particularly attractive biometric challenge. Most of the face recognition research performed in the past used 2D intensity images. However, algorithms based on 2D images are not robust to changes of illumination in the environment or orientation of the subject. The ability to acquire 3D scans of human faces removes those ambiguities, since they capture the exact geometry of the subject, invariant to illumination and orientation changes. Unencumbered by those limitations, research in 3D face recognition is now beginning to address a different source of error in biometric recognition: facial geometry deformation caused by facial expressions, which can make 3D algorithms which treat 3D faces as rigid surfaces fail. In this paper, a 3D face recognition framework is proposed to tackle this problem. The framework is composed of three subsystems: expression recognition system, expressional face recognition system and neutral face recognition system. In particular, a system for the recognition of faces with one type of expression (smile) and neutral faces was implemented and tested on a database of 30 subjects. The results proved the feasibility of this framework.

Algorithms↗
PubMed1996

Face processing: human perception and principal components analysis.

Principal components analysis (PCA) of face images is here related to subjects' performance on the same images. In two experiments subjects were shown a set of faces and asked to rate them for distinctiveness. They were subsequently shown a superset of faces and asked to identify those that had appeared originally. Replicating previous work, we found that hits and false positives (FPs) did not correlate: Those faces easy to identify as being "seen" were unrelated to those faces easy to reject as being "unseen." PCA was performed on three data sets: (1) face images with eye position standardized, (2) face images morphed to a standard template to remove shape information, and (3) the shape information from faces only. Analyses based on PCA of shape-free faces gave high predictions of FPs, whereas shape information itself contributed only to hits. Furthermore, whereas FPs were generally predictable from components early in the PCA, hits appeared to be accounted for by later components. We conclude that shape and "texture" (the image-based information remaining after morphing) may be used separately by the human face processing system, and that PCA of images offers a useful tool for understanding this system.

Adult↗
PubMed1981

Unilateral face-bows: a theoretical and laboratory analysis.

The investigation evaluated and compared the effectiveness of five face-bow types in delivering unilateral distal forces to their inner-bow terminals. The face-bow types evaluated were bilaterally symmetrical, soldered offset, spring attachment, swivel offset, and power arm. A strain-gauge transducer system was used in the laboratory analysis. A theoretical analysis was also conducted, patterned after the method of Haack and Weinstein, and the results were compared to those obtained from the laboratory analysis. The method used for the theoretical evaluation of the sample face-bows was found to be a reliable means of approximating the percentage distribution of distal forces to the inner-bow terminals. The magnitude and direction of the net lateral forces delivered to the inner-bow terminals was also reliably determined. The results of the theoretical and experimental study of the five face-bow types indicate that the power-arm unilateral face-bow and the swivel-offset unilateral face-bow were effective in delivering a clinically significant unilateral distal force. The bilaterally symmetrical face-bow, the soldered-offset unilateral face-bow, and the spring-attachment unilateral face-bow were not effective in delivering clinically significant unilateral distal forces. Every face-bow effective in delivering unilateral distal forces will also deliver a net lateral force to the inner-bow terminals. This net lateral force will have a direction running from the inner-bow terminal receiving the greater distal force toward the terminal receiving the lesser distal force.

Biomechanical Phenomena↗
PubMed1990

The Faces Pain Scale for the self-assessment of the severity of pain experienced by children: development, initial validation, and preliminary investigation for ratio scale properties.

Altogether 553 children (195 first graders, mean age 6.8 years, and 358 third graders, mean age 8.7 years) participated in the development of a self-report measure to assess the intensity of children's pain. The first step was the derivation, from children's drawings of facial expressions of pain, of 5 sets of 7 schematic faces depicting changes in severity of expressed pain from no pain to the most pain possible. With the set of faces that achieved the highest agreement in pain ordering, additional studies were conducted to determine whether the set had the properties of a scale. In one study, children rank-ordered the faces on 2 occasions, separated by 1 week. All 7 faces were correctly ranked by 64% (retest 1 week later, 61%) of grade 1 children and by 86% (retest 89%) of grade 3 children. In a second study, the faces were presented in all possible paired combinations. All 7 faces were correctly placed by 62% (retest 86%) of the younger and by 75% (retest 71%) of the older subjects. A third study asked children to place faces along a scale: a procedure allowing a check on the equality of intervals. The fourth study checked on whether pain was acting as an underlying construct for ordering the faces in memory. We asked whether children perceived the set as a scale by asking if memory for an ordered set of faces was more accurate than for a random set. The final study checked, with 6-year-old children, the test-retest reliability of ratings for recalled experiences of pain. Overall, the faces pain scale incorporates conventions used by children, has achieved strong agreement in the rank ordering of pain, has indications that the intervals are close to equal, and is treated by children as a scale. The test-retest data suggest that it may prove to be a reliable index over time of self-reported pain.

Child↗
PubMed1988

Patterns of vertical growth in the face.

The purpose of this study was to examine the patterns of facial growth development in subjects with skeletal open-bite and skeletal deep-bite faces. Longitudinal data based on lateral cephalometric radiographs of 16 male and 16 female subjects, ages 3 through 18 years, were used. These subjects were selected on the basis of lower face height as a percentage of total face height. Persons exhibiting extreme values were selected to create four groups with eight subjects in each group. Curves of absolute and incremental growth for total anterior face height, upper anterior face height, lower anterior face height, posterior face height, and ramal length were analyzed statistically and graphically. It was established that the anterior dimensions of the face demonstrated typologically divergent patterns of development in open- and deep-bite faces. Further, the posterior dimensions of the face did not discriminate between these two typological groups. The female open-bite subjects were earliest in the timing of the adolescent growth spurt, followed in succession by deep-bite female subjects, open-bite male subjects, and finally the deep-bite male subjects. The clinical implications of these observations pertain to the timing of orthodontic treatment, the length of retention period, and the prediction of adult occlusal status during the mixed dentition.

Adolescent↗
PubMed1994

Associative ERP effects with memories of artificial faces.

A previous study (Valdes-Sosa and Bobes, 1990) described a negative ERP component evoked by mis-matches in a face-feature matching task, using photographs of real faces. This component could be N400 (or an analogue), elicited by associative priming within a non-linguistic domain: that of face structure. To confirm this it is necessary to demonstrate that semantic/linguistic recoding was not a necessary condition in triggering the negativity. This means falsifying what we call the 'priming by proxy' hypothesis, and locating the triggering mis-match within face structure. In this paper subjects studied artificial schematic faces over several sessions, and 1 week later were presented with a face-feature matching task with simultaneous ERP recording. Since no semantic information or verbal labels were available, eliciting a mis-match negativity with these faces contradicts the 'priming by proxy' hypothesis. In a first experiment, in which the subjects learning was controlled through a face familiarity decision task, no significant mis-match negativity was found. However, in a second experiment in which learning was controlled through a forced-choice face-feature match, a significant mis-match negativity was found in the subsequent recording session. This result supports the idea that a component similar to N400 can be elicited by an associative mis-match restricted to the face-structural domain.

Adolescent↗