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Schizophrenia and affective disorder show different visual scanning behavior for faces: a trait versus state-based distinction?

BACKGROUND: Abnormal visual scanpaths to faces and facial expressions in schizophrenia may underlie schizophrenic subjects' disturbed interpersonal communication. This study is the first to examine the specificity of these impairments to schizophrenia, by including an affective disorder psychiatric control group. METHODS: The visual scanpath performance of 65 schizophrenia, 52 affective disordered, and 61 control subjects were compared in two experiments. In the "face recognition" experiment, subjects viewed four identifiable (non-degraded) neutral faces versus four matched non-identifiable (degraded) control faces. In the "facial affect recognition" experiment, subjects viewed positive (happy), negative (sad), and neutral (control) facial emotion stimuli. Concurrent behavioral tasks were face matching (face recognition) and expression matching (facial affect recognition), each under two multiple-choice conditions (7 or 3 options). RESULTS: Scanpath disturbances were most apparent in schizophrenia subjects, who maintained a comparatively "restricted" scanpath style to all face stimuli. Schizophrenics subjects also showed the greatest recognition difficulties, particularly for neutral and happy faces. Scanpath parameters for affective disorder subjects differed only from the schizophrenia (but not the control) group, except for attention to facial features where they generally avoided facial features in all expressions and showed the greatest attentional problems of all groups for degraded faces. CONCLUSIONS: Our results suggest that a global restriction of visual scanpaths is specific to schizophrenic psychosis and might be a trait marker for this disorder, whereas scanpath abnormalities in affective disorder might instead reflect severe state-based (or discrete) attentional disturbances.

Adult↗

Covert face recognition in prosopagnosia: a dissociable function?

Covert face recognition was investigated in a patient with prosopagnosia without object agnosia. This patient performed well in various face processing tasks like expression analysis and feature processing and had relatively preserved semantic knowledge about persons, but was slightly impaired in the visual matching of unfamiliar faces. In face-name paired-associate relearning task, covert face recognition was demonstrated to be above-chance. However, as this task cannot be meaningfully applied to control subjects, results do not necessarily indicate that the degree of covert face recognition is normal. In fact, in contrast to control subjects, the patient showed significantly reduced associative priming of names by face primes as compared to name primes, suggesting a quantitative reduction of covert face recognition. It is argued that these results support the view that overt and covert face recognition are brought about by the same functional system (Farah, O'Reilly and Vecera, 1993).

Adult↗

Digitizing the moving face during dynamic displays of emotion.

Humans typically decode facial signals during dynamic interactions in which the face moves. In this study, we digitized real time video signals in order to examine movement asymmetries across the face during emotional and nonemotional expressions. Forty dextral males were tested. For each expression, a 400 ms video segment was analyzed for changes in signal value (pixel intensity) over consecutive frames. The upper and lower face regions were examined separately due to differences in the cortical enervation of facial muscles in the upper (bilateral) vs lower face (contralateral). Results revealed distinctly different movement asymmetries over the lower and upper hemiface. In the upper face, more movement occurred over the right side for most facial expressions, regardless of emotionality. The latter finding questions the assumption that muscles of the upper face are symmetrical and/or bilaterally enervated in a symmetrical manner. In the lower face, negative expressions linked to fight-flight emotions (i.e. fear, anger) were associated with greater left sided movement, whereas happiness tended to be associated with more right sided movement. No consistent pattern of movement asymmetry occurred for nonemotional expressions. Although the valence-related movement asymmetries in the lower face are consistent with neuropsychological models of emotional expressivity, it remains unclear whether they reflect activation or inhibitory hemispheric mechanisms. Taken together, these data suggest that multiple factors may contribute to expressive movement asymmetries of the face.

Adolescent↗

Stimulus-specific effects in face recognition over changes in viewpoint.

Individual faces vary considerably in both the quality and quantity of the information they contain for recognition and for viewpoint generalization. In the present study, we assessed the typicality, recognizability, and viewpoint generalizability of individual faces using data from both human observers and from a computational model of face recognition across viewpoint change. The two-stage computational model incorporated a viewpoint alignment operation and a recognition-by-interpolation operation. An interesting aspect of this particular model is that the effects of typicality it predicts at the alignment and recognition stages dissociate, such that face typicality is beneficial for the success of the alignment process, but is adverse for the success of the recognition process. We applied a factor analysis to the covariance data for the human- and model-derived face measures across the different viewpoints and found two axes that appeared consistently across all viewpoints. Projection scores for individual faces on these axes (i.e. the extent to which a face's 'performance profile' matched the pattern of human- and model-derived scores on that axis), correlated across viewpoint changes to a much higher degree than did the raw recognizability scores of the faces. These results suggest that the stimulus information captured in the model measures may underlie distinct and dissociable aspects of the recognizability of individual faces across viewpoint change.

Computer Simulation↗

Face processing in adolescents with autistic disorder: the inversion and composite effects.

Two experiments with upright and inverted face and object images were carried out to investigate whether face processing in autism is more feature-based than in individuals with typical development. Participants were 17 high-ability adolescents with autistic disorder (16-24 years), 24 typically developing children (9-10 years) and 16 adults (18-33 years). In Experiment 1, a normal inversion effect was found for the adolescents with autism in a standard face recognition paradigm with reduced memory demands, except for a subgroup with low social intelligence who were not better in recognizing upright relative to inverted photographs of faces. In Experiment 2, the group with autism did not show the composite effect like the adult group did: they recognized face halves as well in aligned composite faces as in non-aligned composite faces. The results on the inversion task suggest that most adolescents with autism form a normal configuration-based face representation, but the absence of the composite effect indicates that they are less prone to use the contextual information of the face in a visual-search task.

Adolescent↗

An intrusive impact of anchors in children's faces pain scales.

The numerous pain rating scales using faces depicting varying degrees of distress to elicit reports of pain from children fall into two categories; those with a neutral face as the 'no pain' anchor, and those with a smiling face as the 'no pain' anchor. This study examined the potentially biasing impact of these anchor types on children's self-reports of pain in response to a series of vignettes. Participants were 100 children stratified by age (5-6 years, 7-8 years, 9-12 years) and randomly assigned to one of three groups: (1) neutral scale/sensory instructions; (2) smiling scale/sensory instructions; (3) smiling scale/affective instructions. Children completed a faces scale, a VAS, and emotions ratings in response to four scenarios depicting: (1) no pain/negative emotions; (2) pain/negative emotions; (3) no pain/positive emotions: (4) pain/positive emotions. Results showed that children who used the smiling scale had significantly higher pain scores for no pain and pain/negative emotions vignettes and significantly lower faces scale scores for pain/positive vignettes than children who used the neutral faces scale. Instructions varying in focus on sensory or affective qualities of pain had no effect on children's pain ratings. Group differences in children's ratings with the VAS and emotions measure suggested that rating pain with a smiling faces scale may alter a child's concept of pain. Age differences indicated the younger children rated the negative emotion vignettes as more painful than the older children. These findings suggest that children's pain ratings vary depending on the types of faces scale used, and that faces scales with smiling anchors may confound affective states with pain ratings.

Aging↗

Disorders of face perception and recognition.

Face recognition is one of the most complex visual tasks performed by the human brain. Data from monkeys suggest that area IT may play a key role in identifying faces, and functional imaging research suggests that the human homologue of IT may be located in the medial occipitotemporal cortex, where a FFA has been located. Damage to medial occipitotemporal structures on the right or bilaterally leads to prosopagnosia, the failure to recognize facial identity. Prosopagnosia is not a single functional disorder but a family of dysfunctions, with different patients having different degrees of impairments to various perceptual and memory stages involved in face processing. Understanding the perceptual basis of this disorder and epiphenomena, such as covert recognition, is a goal of current research. Deficits in face perception also may contribute to Capgras syndrome and may be related to the impaired social development of patients with Asperger syndrome. More recently, identified deficits in face processing include the false recognition of unfamiliar faces and the impaired extraction of social information from faces, independent of the recognition of identity. Many of these prosopagnosia and other face processing deficits can be placed in the context of cognitive models of face processing stages, which are being refined continually by data from neurologic patients and functional imaging in normal subjects.

Asperger Syndrome↗

Comparison of face masks in the bag-mask ventilation of a manikin.

BACKGROUND AND OBJECTIVE: We conducted a study investigating the effectiveness of four face mask designs in the bag-mask ventilation of a special manikin adapted to simulate a difficult airway. METHODS: Forty-eight anaesthetists volunteered to bag-mask ventilate the manikin for 3 min with four different face masks. The primary outcome of the study was to calculate mean percentage leak from the face masks over 3 min. Anaesthetists were also asked to rate the face masks using a visual analogue score. RESULTS: The single-use scented intersurgical face mask had the lowest mean leak (20%). This was significantly lower than the mean leak from the single-use, cushioned 7,000 series Air Safety Ltd. face mask (24%) and the reusable silicone Laerdal face mask (27%) but not significantly lower than the mean leak from the reusable anatomical intersurgical face mask (23%). CONCLUSIONS: There was a large variation in both performance and satisfaction between anaesthetists with each design. This highlights the importance of having a variety of face masks available for emergency use.

Anesthesia↗

The perception of four basic emotions in human and nonhuman faces by children with autism and other developmental disabilities.

Children who experienced autism, mental retardation, and language disorders; and, children in a clinical control group were shown photographs of human female, orangutan, and canine (boxer) faces expressing happiness, sadness, anger, surprise and a neutral expression. For each species of faces, children were asked to identify the happy, sad, angry, or surprised expressions. In Experiment 1, error patterns suggested that children who experienced autism were attending to features of the lower face when making judgements about emotional expressions. Experiment 2 supported this impression. When recognizing facial emotion, children without autism performed better when viewing the full face, compared to the upper and lower face alone. Children with autism performed no better when viewing the full face than they did when viewing partial faces; and, performed no better than chance when viewing the upper face alone. The results are discussed with respect to differences in the manner that children with and without autism process social information communicated by the face.

Affect↗

Face and mouth inversion effects on visual and audiovisual speech perception.

Three experiments examined whether image manipulations known to disrupt face perception also disrupt visual speech perception. Research has shown that an upright face with an inverted mouth looks strikingly grotesque whereas an inverted face and an inverted face containing an upright mouth look relatively normal. The current study examined whether a similar sensitivity to upright facial context plays a role in visual speech perception. Visual and audiovisual syllable identification tasks were tested under 4 presentation conditions: upright face-upright mouth, inverted face-inverted mouth, inverted face-upright mouth, and upright face-inverted mouth. Results revealed that for some visual syllables only the upright face-inverted mouth image disrupted identification. These results suggest that upright facial context can play a role in visual speech perception. A follow-up experiment testing isolated mouths supported this conclusion.

Adult↗

Monkeys and mug shots: cues used by rhesus monkeys (Macaca mulatta) to recognize a human face.

We investigated the cues rhesus monkeys (Macaca mulatta) use to recognize a familiar human face. To manipulate facial cues, schematic faces were constructed with Identi-Kit materials derived from mug shots. The monkeys (N = 4) spontaneously classed Identi-Kit as faces on initial presentations. The monkeys then learned to distinguish one Identi-Kit face, the standard, from others. Panel presses indicated recognition of the standard face. Eye movement recordings revealed that the monkeys predominantly fixated on the eyes of the standard face. When the standard face was transformed by removing, altering, or reorienting its features, only alterations of eyes or brows lowered recognition; removal of eyes, brows, nose, or lips did not. Responses to rotated, inverted, and scrambled versions of the standard face varied but generally disrupted recognition. We concluded that features and configuration were used to recognize the human face.

Animals↗

Modulation of focused attention by faces expressing emotion: evidence from flanker tasks.

Three experiments evaluated whether facial expression can modulate the allocation of focused attention. Identification of emotionally expressive target faces was typically faster when they were flanked by identical (compatible) faces compared with when they were flanked by different (incompatible) faces. This flanker compatibility effect was significantly smaller when target faces expressed negative compared with positive emotion (see Experiment 1A); however, when the faces were altered to disrupt emotional expression, yet retain feature differences, equal flanker compatibility effects were observed (see Experiment 1B). The flanker-compatibility effect was also found to be smaller for negative target faces compared compatibility with neutral target faces, and for both negative and neutral target faces compared with positive target faces (see Experiment 2). These results suggest that the constriction of attention is influenced by facial expressions of emotion.

Adult↗

Perceptual interference supports a non-modular account of face processing.

The perception of faces and of nonface objects share common early visual processing stages. Some argue, however, that the brain eventually processes faces separately from other objects, within a domain-specific module dedicated to face perception. This apparent specialization for faces could, alternatively, result from people's expertise with this category of stimuli. Here we used behavioral and electrophysiological measures of interference to address the functional independence of face and object processing. If the expert processing of faces and cars depend on common mechanisms related to holistic perception (obligatory processing of all parts), then for human subjects who are presumed to be face experts, car perception should interfere with concurrent face perception. Furthermore, such interference should increase with greater expertise in car identification, and indeed this is what we found. Event-related potentials (ERPs) suggest that this interference arose from perceptual processes contributing to the holistic processing of both objects of expertise and faces.

Adolescent↗

The functional anatomy of the lower face as it applies to rejuvenation via chemodenervation.

Botulinum toxin type A (Botox) injections have revolutionized nonsurgical rejuvenation of the upper face since their introduction in the early 1990s. Their use in the lower face has not become nearly as popular. The key to using Botox to improve the appearance of the lower face lies in understanding the functional anatomy of the lower face musculature. Although the facial plastic surgeon should be familiar with the muscles of the lower face and anatomic variations, the functional anatomy of the lower face varies widely from patient to patient and even more from one side of the face to the other. Understanding how the lower face moves is the key to using Botox to improve nasolabial folds, perioral rhytids, chin dimpling, marionette's lines, and downturned oral commissures. This is not an area for the novice injector, as a few stray units are not tolerated nearly so well as they are in the upper face.

Botulinum Toxins, Type A↗

It takes a confounded face to pop out of a crowd.

It is widely reported that a picture of an angry face seems to figuratively pop out of an array of happy faces, although all of these reports are based on a single experiment by Hansen and Hansen. Pop out, when it occurs, indicates that an observer has located the target by means of a preattentive, parallel search. Hansen and Hansen concluded that it was the affect displayed by the face which caused it to pop out from its surrounding distracters. However, Hansen and Hansen's angry faces contained extraneous dark areas which were introduced when they transformed Ekman and Friesen's photographs of angry and happy faces into black-on-white sketches. When the original artifact-free gray-scaled versions of angry and happy faces were used no evidence for pop out was found. All target faces were found during a serial, self-terminating search regardless of their expression. The angry face in Hansen and Hansen's experiments may have popped out from a crowd of happy faces because of a contrast artifact inadvertently introduced when they created their stimuli.

Artifacts↗

Knowledge of famous faces and names in semantic dementia.

Semantic dementia is a focal clinical syndrome, resulting from degeneration of the temporal lobes and characterized by progressive loss of conceptual knowledge about the world. Because of the highly circumscribed nature of the disorder it is a natural model for improving understanding of how semantic information is cerebrally represented. There is currently a lack of consensus. One view proposes the existence of modality specific meaning systems, in which visual and verbal information are stored separately. An opposing view assumes that information is represented by a unitary, amodal semantic system. The present study explores these alternatives in an examination of famous face and name knowledge in 15 patients with semantic dementia. The study of face recognition in patients with an established semantic disorder also permits an examination of the relationship between semantic dementia and the focal clinical syndrome of progressive prosopagnosia. The semantic dementia patients were profoundly impaired on both face and name identification and familiarity judgement tasks compared with amnesic patients with Alzheimer's disease and healthy controls. However, whereas the two reference groups performed better for names than faces, the semantic group showed the opposite pattern. This overall profile masked individual differences: semantic dementia patients with predominant left temporal lobe atrophy showed better recognition of names than faces, whereas patients with right temporal predominance showed the reverse pattern. Relative superiority for names or faces was mirrored by corresponding superiority for words or pictures on a standard semantic test. We interpret the findings as inconsistent with a unitary, amodal model of semantic memory. However, the data are not wholly compatible with a strict multiple system account. The data favour a model of semantic memory comprising a single interconnected network, with dedicated brain regions representing modality specific information. The data emphasize the importance of the anterior, inferolateral parts of the left temporal lobe for the representation of names and the corresponding parts of the right temporal lobe for faces. Dissociations between face and name knowledge provide a challenge for existing models of face processing. Moreover, they lead us to argue that the focal syndrome of progressive prosopagnosia is one of the clinical presentations of semantic dementia and not a separate clinical entity.

Aged↗

Pain evaluation in the intensive care unit: observer-reported faces scale compared with self-reported visual analog scale.

BACKGROUND AND OBJECTIVES: The visual analog scale (VAS) is a simple and sensitive mean of pain assessment. The faces scale is also a simple, self-reporting method for children. Facial signs of pain have not been used to assess pain in postoperative adult patients in the intensive care unit (ICU). METHODS: Fifty patients undergoing esophageal cancer surgery by a thoracoabdominal procedure were studied. Epidural opioids, such as morphine or buprenorphine, combined with bupivacaine were administered during and after surgery. Pain measurement was performed by a physician in the ICU using the self-reported VAS 0.5, 1, 2, 4, and 6 hours after tracheal extubation and thereafter every 4 hours during the stay in the ICU. A nurse who was unaware of the patients' VAS scores assessed facial expression as a measure of pain intensity using a five-grade faces scale immediately before pain evaluation by VAS. The VAS was rescaled into five discrete units that would match the five faces scale scores. Weighted kappa statistics were used to establish a relative level of agreement between the five-grade VAS and faces scale. RESULTS: Good agreement was found between the five-grade VAS and the faces scale 30 minutes and 1 hour after tracheal extubation (weighted kappa values .67 and .62, respectively). The VAS and faces scales were measured 7-13 times per patient during the stay in the ICU, and 518 observations were collected. Although moderate agreement was found between the five-graded VAS and faces scale for all pairs of observation (weighted kappa values .54), less agreement was found between them in patients with moderate pain. In addition, the calculated mean differences between the five-graded VAS and faces scale differed significantly between patients. CONCLUSION: The faces scale may be useful for pain evaluation in the ICU.

Adult↗

Evolutionary search for faces from line drawings.

Single 2D line drawing is a straightforward method to illustrate 3D objects. The faces of an object depicted by a line drawing give very useful information for the reconstruction of its 3D geometry. Two recently proposed methods for face identification from line drawings are based on two steps: finding a set of circuits that may be faces and searching for real faces from the set according to some criteria. The two steps, however, involve two combinatorial problems. The number of the circuits generated in the first step grows exponentially with the number of edges of a line drawing. These circuits are then used as the input to the second combinatorial search step. When dealing with objects having more faces, the combinatorial explosion prevents these methods from finding solutions within feasible time. This paper proposes a new method to tackle the face identification problem by a variable-length genetic algorithm with a novel heuristic and geometric constraints incorporated for local search. The hybrid GA solves the two combinatorial problems simultaneously. Experimental results show that our algorithm can find the faces of a line drawing having more than 30 faces much more efficiently. In addition, simulated annealing for solving the face identification problem is also implemented for comparison.

Algorithms↗