Prosopagnosia: a defect in visual configural processing

A patient with severe, lasting prosopagnosia could not get an immediate overview of a face sufficiently specific for successful identification. He also failed completely in tasks of visual closure despite adequate performances on numerous other tests of visual perception and memory. We conclude that prosopagnosia represents a loss of visual "configural processing"--a learned skill enabling immediate identification of individual members of a class without conscious visuospatial analysis or remembering. Prosopagnosia and agnosic alexia represent two distinct defects of configural processing: Alexics cannot identify items with distinctive features that are themselves identifiable. Prosopagnosics cannot identify objects whose critical distinguishing features have no independent identities.     

Older adults' configural processing of faces: role of second-order information

Problems with face recognition are frequent in older adults. However, the mechanisms involved have only been partially discovered. In particular, it is unknown to what extent these problems may be related to changes in configural face processing. Here, we investigated the face inversion effect (FIE) together with the ability to detect modifications in the vertical or horizontal second-order relations between facial features. We used a same/different unfamiliar face discrimination task with 33 young and 33 older adults. The results showed dissociations in the performances of older versus younger adults. There was a lack of inversion effect during the recognition of original faces by older adults. However, for modified faces, older adults showed a pattern of performance similar to that of young participants, with preserved FIE for vertically modified faces and no detectable FIE for horizontally modified faces. Most importantly, the detection of vertical modifications was preserved in older relative to young adults whereas the detection of horizontal modifications was markedly diminished. We conclude that age has dissociable effects on configural face-encoding processes, with a relative preservation of vertical compared to horizontal second-order relations processing. These results help to understand some divergent results in the literature and may explain the spared familiar face identification abilities in the daily lives of older adults.     

Face‐specific configural processing of relational information

Face processing relies on configural processing, which is thought to be particularly disrupted by inversion. We compared inversion effects in recognition experiments for three types of stimuli, using faces (Experiment 1) and houses (Experiment 2). Stimuli varied by their colour only (colour), by the spatial relations between components (relational), or by the components themselves (eyes, mouths, doors). For faces, relational versions revealed strong inversion effects, component versions moderate, and colour versions no inversion effect. Recognition of houses revealed no inversion effects at all. We suggest that the inversion effects observed for faces in the component condition are due to relational changes, which must accompany any change in components. This proposal may account for the rather inconsistent effects of inversion reported in the literature. Furthermore, we suggest configural processing seems to be somehow face‐specific.     

Face gender recognition in developmental prosopagnosia: Evidence for holistic processing and use of configural information

Face identification deficits in developmental prosopagnosics (DPs) have been thought to be due to general difficulties with processing configural face information and integrating configural and parts information into a coherent whole (holistic processing). Gender recognition provides a further opportunity to more fully examine this issue as this ability may be intact in DPs and it has been shown to depend on processing configural information and holistic processing in neurotypical individuals. In the present study we first determined that, indeed, gender discrimination performance was similar in DPs and controls. Second, we found that inversion and scrambling (which we propose measures holistic processing and sensitivity to configural information, respectively) produced comparable deficits in DPs and controls, suggesting that both groups use holistic processing and configural information to recognize gender. This indicates that holistic processing and using configural face information are not general impairments in DP and may be more specific to face identity.     

The role of attention in processing configural and shape information in 3-D novel objects

Recent research suggests that there is an advantage for processing configural information in scenes and objects. The purpose of this study was to investigate the extent to which attention may account for this configural advantage. In Experiment 1, we found that cueing the location of change in single object displays improved detection performance for both configural and shape changes, yet cueing attention away from the location of change was detrimental only for shape change detection. A configural advantage was present for each cueing condition. Experiments 2A and 2B examined whether the configural advantage persisted in conditions where attention was distributed more widely, using a visual search paradigm. Although searches for configural changes were faster than those for shape changes across all set sizes, both types of information appeared to be processed with similar efficiency. Overall, these results suggest that the configural advantage is independent of the location or distribution of visual attention.     

Face recognition in 4- to 7-year-olds: processing of configural, featural, and paraphernalia information.

We tested 4- to 7-year-old children's face recognition by manipulating the faces' configural and featural information and the presence of superfluous paraphernalia. Results indicated that even with only a single 5-s exposure to the target face, most children could use configural and feature cues to make identity judgments. Repeated exposure and experimenter feedback enabled other children to do so as well. Even after attaining proficiency at identifying the target face, however, children's recognition was impaired when a superfluous hat was added to the face. Thus, although young children can process featural and configural face information, their memories are highly susceptible to disruption from superfluous paraphernalia.     

Perceptual specialization and configural face processing in infancy

Adults’ face processing expertise includes sensitivity to second-order configural information (spatial relations among features such as distance between eyes). Prior research indicates that infants process this information in female faces. In the current experiments, 9-month-olds discriminated spacing changes in upright human male and monkey faces but not in inverted faces. However, they failed to process matching changes in upright house stimuli. A similar pattern of performance was exhibited by 5-month-olds. Thus, 5- and 9-month-olds exhibited specialization by processing configural information in upright primate faces but not in houses or inverted faces. This finding suggests that, even early in life, infants treat faces in a special manner by responding to changes in configural information more readily in faces than in non-face stimuli. However, previously reported differences in infants’ processing of human versus monkey faces at 9 months of age (but not at younger ages), which have been associated with perceptual narrowing, were not evident in the current study. Thus, perceptual narrowing is not absolute in the sense of loss of the ability to process information from other species’ faces at older ages.     

Sequential effects on speeded information processing: a developmental study

Two experiments were performed to assess age-related changes in sequential effects on choice reaction time (RT). Sequential effects portray the influence of previous trials on the RT to the current stimulus. In Experiment 1, three age groups (7-9, 10-12, and 18-25 years) performed a spatially compatible choice task, with response-to-stimulus intervals (RSIs) of 50 and 500 ms varied between trial blocks. In Experiment 2, three age groups (7-9, 15-16, and 18-25 years) performed the task with spatial stimulus-response (S-R) mappings (compatible versus incompatible) varied between participants. For adults, the experiments yielded a pattern of sequential effects suggestive of "automatic facilitation" (i.e., a first-order repetition effect and a higher order benefit-only pattern for short RSIs) and "subjective expectancy" (i.e., a first-order alternation effect and a higher order cost-benefit pattern for long RSIs). Automatic facilitation was more pronounced for incompatible responses than for compatible responses. Both experiments showed the anticipated decrease in automatic facilitation with advancing age. Finally, the first-order alternation effect showed the predicted age-related increase, but the cost-benefit pattern revealed an opposite trend, suggesting that the first-order and higher order indexes of subjective expectancy may relate to dissociable mechanisms.     

Connectedness affects dot numerosity judgment: Implications for configural processing

Participants judged the number of dots in visual displays with brief presentations (200 msec), such that the numerosity judgment was based on an instantaneous impression without counting. In some displays, pairs of adjacent dots were connected by line segments, whereas, in others, line segments were freely hanging without touching the dots. In Experiments 1, 2A, and 2B, connecting pairs of dots by line segments led to underestimation of dot numbers in those patterns. In Experiment 3, we controlled for the number of freely hanging line segments, whereas Experiment 4 showed that line segments that were merely attached to dots without actually connecting them did not produce a considerable underestimation effect. Experiment 5 showed that a connectedness effect existed when stimulus duration was reduced (50 msec) or extended (1,000 msec). We conclude that connectivity affects dot numerosity judgments, consistent with earlier findings of a configural effect in numerosity processing. Implications of the role of connectedness in object representation are discussed.     

Evidence of a shift from featural to configural face processing in infancy

Two experiments examined whether 4-, 6-, and 10-month-old infants process natural looking faces by feature, i.e. processing internal facial features independently of the facial context or holistically by processing the features in conjunction with the facial context. Infants were habituated to two faces and looking time was measured. After habituation they were tested with a habituation face, a switch-face, or a novel face. In the switch-faces, the eyes and mouth of the habituation faces were switched. The results showed that the 4-month-olds processed eyes and mouth by feature, whereas the 10-month-olds processed both features holistically. The 6-month-olds were in a transitional stage where they processed the mouth holistically but the eyes still as a feature. Thus, the results demonstrated a shift from featural to holistic processing in the age range of 4 to 10 months.     

Featural and configural face processing in adults and infants: a behavioral and electrophysiological investigation

We sought to elucidate the behavioral and electrophysiological correlates of face processing, in adults and infants, by manipulating either the featural or configural information within the face. Two different experiments are reported. In these experiments, event-related potentials (ERPs) were recorded from the scalp while adult, 8-month-old, and 4-month-old participants completed configural-change and featural-change face tasks. The infants also completed a behavioral visual paired-comparison task with featural and configural face changes. ERP results reveal hemispheric differences in processing featural but not configural changes for the N170 in adults. Furthermore, featural and configural changes are processed differently within the right and left hemispheres. The right hemisphere N170 is significantly greater for configural compared to featural changes. The left hemisphere N170, however, exhibits the opposite effect. Infant data suggest that similar to adults, 8-month-old, but not 4-month-old participants, exhibit similar hemispheric differences between featural and configural changes for the P400 component. Behavioral results suggest increased sensitivity to both featural and configural face changes in 8-month-olds compared to 4-month-olds.     

The face-inversion effect as a deficit in the encoding of configural information: direct evidence

We report four experiments leading to conclusions that: (i) the face-inversion effect is mainly due to the deficits in processing of configural information from inverted faces; and (ii) this effect occurs primarily at the encoding stage of face processing, rather than at the storage stage. In experiment 1, participants discriminated upright faces differing primarily in configuration with 81% accuracy. Participants viewing the same faces presented upside down scored only 55%. In experiment 2, the corresponding discrimination rates for faces differing mainly in featural information were 91% (upright) and 90% (inverted). In experiments 3 and 4, the same faces were used in a memory paradigm. In experiment 3, a delayed matching-to-sample task was used, in which upright-face pairs differed either in configuration or features. Recognition rates were comparable to those for the corresponding upright faces in the discrimination tasks in experiments 1 and 2. However, there was no effect of delay (1 s, 5 s, or 10 s). In experiment 4, we repeated experiment 3, this time with inverted faces. Results were comparable to those of inverted conditions in experiments 1 and 2, and again there was no effect of delay. Together these results suggest that an 'encoding bottleneck' for configural information may be responsible for the face-inversion effect in particular, and memory for faces in general.     

Perceptual integrality of componential and configural information in faces

The relative contribution of componential and configural information to face perception is controversial. We addressed this issue in the present study by examining how componential information and configural information interact during face processing, using Garner’s (1974) speeded classification paradigm. When classifying upright faces varying in components (eyes, nose, and mouth) and configural information (intereyes and nose-mouth spacing), observers could not selectively attend to components without being influenced by irrelevant variation in configural information, and vice versa, indicating that componential information and configural information are integral in upright face processing. Performance with inverted faces showed selective attention to components but not to configural information, implying dominance of componential information in processing inverted faces. When faces varied only in components, selective attention to different components was observed in upright and inverted faces, indicating that facial components are perceptually separable. These results provide strong evidence that integrality of componential and configural information, rather than the relative dominance of either, is the hallmark of upright face perception.     

Semantic access processing in a supra-modal deficit: a single case study

The case is presented of a semantic dementia patient, who shows a deficit selective for (i) conceptual class (living things), (ii) attribute processing (visual features) and affecting (iii) input-output modalities at the same processing stage (matching stored representation to attributes). The first experimental part aims at exploring the specific stage/process at which semantic knowledge breaks down through multi-modality tasks, devised to tap different levels within the semantic elaboration flow. The second focuses on the differences between category vs. attribute knowledge across various modalities. The core nature of the patient's deficit is investigated through a close comparison of her damage to a specific processing stage across modalities in the light of her class and attribute-specific impairment. The complex pattern of findings is discussed according to current theoretical accounts of semantic memory organization. Finally, the relevance of the adoption of a broad perspective when dealing with semantic memory impairments is highlighted.     

Internal feature saliency as a marker of familiarity and configural processing

Two experiments that explore the internal feature advantage (IFA) in familiar face processing are reported. The IFA involves more efficient processing of internal features for familiar faces over unfamiliar ones. Experiment 1 examined the possibility of a configural basis for this effect through use of a matching task for familiar and unfamiliar faces presented both upright and upside-down. Results revealed the predicted IFA for familiar faces when stimuli were upright, but this was removed when stimuli were inverted. Experiment 2 examined the degree of training required before the IFA was demonstrated. Latency results revealed that whilst 90–180 s of exposure was sufficient to generate an IFA of intermediate magnitude, 180–270 s of exposure was required before the IFA was equivalent to that demonstrated for a familiar face. Taken together, these results offer three conclusions: First, the IFA is reaffirmed as an objective indicator of familiarity; second, the IFA is seen to rest on configural processing; and finally, the development of the IFA with familiarity indicates a development of configural processing with familiarity. As such, insight is gained as to the type of processing changes that occur as familiarity is gradually acquired.     

Attention to configural information in change detection for faces

In recent research the change-detection paradigm has been used along with cueing manipulations to show that more attention is allocated to the upper than lower facial region, and that this attentional allocation is disrupted by inversion. We report two experiments the object of which was to investigate how the type of information changed might be a factor in these findings by explicitly comparing the role of attention in detecting change to information thought to be 'special' to faces (second-order relations) with information that is more useful for basic-level object discrimination (first-order relations). Results suggest that attention is automatically directed to second-order relations in upright faces, but not first-order relations, and that this pattern of attentional allocation is similar across features.     

Turning configural processing upside down: part and whole body postures

Like faces, body postures are susceptible to an inversion effect in untrained viewers. The inversion effect may be indicative of configural processing, but what kind of configural processing is used for the recognition of body postures must be specified. The information available in the body stimulus was manipulated. The presence and magnitude of inversion effects were compared for body parts, scrambled bodies, and body halves relative to whole bodies and to corresponding conditions for faces and houses. Results suggest that configural body posture recognition relies on the structural hierarchy of body parts, not the parts themselves or a complete template match. Configural recognition of body postures based on information about the structural hierarchy of parts defines an important point on the configural processing continuum, between recognition based on first-order spatial relations and recognition based on holistic undifferentiated template matching.     

Prosopagnosia and visual object agnosia: A behavioral study

A left-handed woman developed visual object agnosia, prosopagnosia, and visual disorientation after resection of the right occipital lobe. Color agnosia and alexia were absent. When asked to identify objects presented visually, the patient's errors represented visually related objects (underspecifications) or perseverations. Identification was facilitated when she observed the object being used in a natural way. Identification was impaired by surrounding the object with unrelated objects, decreasing the background illumination, decreasing the duration of exposure of the object to the patient, and probably also by decreasing the visual angle subtended by the object. In addition, there were disturbances of visualization (i.e., imaging in the absence of a visual stimulus) that paralleled the perceptual difficulties. We conclude that: (1) A deficit in visual perception, characterized by insufficient feature analysis of visual stimuli, was the basis of the visual agnosia in this case. (2) The visual agnosia could not be explained by (a) a vision-language disconnection syndrome, (b) decay of visual memory traces, or (c) deficiencies in the visual fields (pathologic Funktionswandel). (3) The ability to visualize (visual imagery) probably utilizes some of the same neural pathways used in perception. (4) The results in this case probably can be generalized to some but not all cases of visual agnosia; in particular, the deficit in most previously reported patients with prosopagnosia is similar to that of our case. However, agnosic alexia and color agnosia usually have a different neuropsychological basis.     

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.