Remembering parts and wholes: Configural processing in face recollection

In two experiments, we examined the role of configural processing on states of awareness in face recognition. Configural processing was manipulated by presenting upright and inverted faces during study and test. After studying facial photographs of humans (Experiment 1) and horses (Experiment 2), participants provided a remember/know judgement for each recognised test face. In both experiments, disrupted configural processing had selective effects on states of awareness, so that inversion reduced remember, but not know, responses. Experiment 2 revealed disproportionate inversion effects in that the difference in remember responses between upright and inverted items was significant for human faces but not horses. These findings suggest that configural processing facilitates explicit recollection by providing a distinctive combination of nonsalient event attributes.     

The role of the head in configural body processing: Behavioural and electrophysiological evidence from the inversion and scrambling effect

The present study aimed to further explore the role of the head for configural body processing by comparing complete bodies with headless bodies and faceless heads (Experiment 1). A second aim was to further explore the role of the eye region in configural face processing (Experiment 2). Due to that, we conducted a second experiment with complete faces, eyeless faces, and eyes. In addition, we used two effects to manipulate configural processing: the effect of stimulus inversion and scrambling. The current data clearly show an inversion effect for intact bodies presented with head and faces including the eye region. Thus, the head and the eye region seem to be central for configural processes that are manipulated by the effect of stimulus inversion. Furthermore, the behavioural and electrophysiological body inversion effect depends on the intact configuration of bodies and is associated with the N170 as the face inversion effect depends on the intact face configuration. Hence, configural body processing depends not only on the presence of the head but rather on a complete representation of human bodies that includes the body and the head. Furthermore, configural face processing relies on intact and complete face representations that include faces and eyes.     

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.     

Chinese characters elicit face-like N170 inversion effects

Recognition of both faces and Chinese characters is commonly believed to rely on configural information. While faces typically exhibit behavioral and N170 inversion effects that differ from non-face stimuli (Rossion, Joyce, Cottrell, & Tarr, 2003), the current study examined whether a similar reliance on configural processing may result in similar inversion effects for faces and Chinese characters. Participants were engaged in an orientation judgment task (Experiment 1) and a one-back identity matching task (Experiment 2). Across two experiments, the N170 was delayed and enhanced in magnitude for upside-down faces and compound Chinese characters, compared to upright stimuli. The inversion effects for these two stimulus categories were bilateral for latency and right-lateralized for amplitudes. For simple Chinese characters, only the latency inversion effects were significant. Moreover, the size of the right-hemisphere inversion effects in N170 amplitude was larger for faces than Chinese characters. These findings show the N170 inversion effects from non-face stimuli closely parallel effects seen with faces. Face-like N170 inversion effects elicited by Chinese compound characters were attributed to the difficulty of part-whole integration as well as the disrupted regularity in relational information due to inversion. Hemispheric difference in Chinese character processing is also discussed.     

Chinese characters elicit face-like N170 inversion effects

Recognition of both faces and Chinese characters is commonly believed to rely on configural information. While faces typically exhibit behavioral and N170 inversion effects that differ from non-face stimuli (Rossion, Joyce, Cottrell, & Tarr, 2003), the current study examined whether a similar reliance on configural processing may result in similar inversion effects for faces and Chinese characters. Participants were engaged in an orientation judgment task (Experiment 1) and a one-back identity matching task (Experiment 2). Across two experiments, the N170 was delayed and enhanced in magnitude for upside-down faces and compound Chinese characters, compared to upright stimuli. The inversion effects for these two stimulus categories were bilateral for latency and right-lateralized for amplitudes. For simple Chinese characters, only the latency inversion effects were significant. Moreover, the size of the right-hemisphere inversion effects in N170 amplitude was larger for faces than Chinese characters. These findings show the N170 inversion effects from non-face stimuli closely parallel effects seen with faces. Face-like N170 inversion effects elicited by Chinese compound characters were attributed to the difficulty of part-whole integration as well as the disrupted regularity in relational information due to inversion. Hemispheric difference in Chinese character processing is also discussed.     

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 effect of inversion on the encoding of normal and “thatcherized” faces

In the “Thatcher illusion” a face, in which the eyes and mouth are inverted relative to the rest of the face, looks grotesque when shown upright but not when inverted. In four experiments we investigated the contribution of local and global processing to this illusion in normal observers. We examined inversion effects (i.e., better performance for upright than for inverted faces) in a task requiring discrimination of whether faces were or were not “thatcherized”. Observers made same/different judgements to isolated face parts (Experiments 1-2) and to whole faces (Experiments 3-4). Face pairs had the same or different identity, allowing for different process- ing strategies using feature-based or configural information, respectively. In Experiment 1, feature-based matching of same-person face parts yielded only a small inversion effect for normal face parts. However, when feature-based matching was prevented by using the face parts of different people on all trials (Experiment 2) an inversion effect occurred for normal but not for thatcherized parts. In Experiments 3 and 4, inversion effects occurred with normal but not with thatcherized whole faces, on both same- and different-person matching tasks. This suggests that a common configural strategy was used with whole (normal) faces. Face context facilitated attention to misoriented parts in same-person but not in different-person matching. The results indicate that (1) face inversion disrupts local configural processing, but not the processing of image features, and (2) thatcherization disrupts local configural processing in upright faces.     

The face inversion effect—Parts and wholes: Individual features and their configuration

The face inversion effect (FIE) is a reduction in recognition performance for inverted faces (compared to upright faces) that is greater than that typically observed with other stimulus types (e.g., houses). The work of Diamond and Carey, suggests that a special type of configural information, “second-order relational information” is critical in generating this inversion effect. However, Tanaka and Farah concluded that greater reliance on second-order relational information did not directly result in greater sensitivity to inversion, and they suggested that the FIE is not entirely due to a reliance on this type of configural information. A more recent review by McKone and Yovel provides a meta-analysis that makes a similar point. In this paper, we investigated the contributions made by configural and featural information to the FIE. Experiments 1a and1b investigated the link between configural information and the FIE. Remarkably, Experiment 1b showed that disruption of all configural information of the type considered in Diamond and Carey's analysis (both first and second order) was effective in reducing recognition performance, but did not significantly impact on the FIE. Experiments 2 and 3 revealed that face processing is affected by the orientation of individual features and that this plays a major role in producing the FIE. The FIE was only completely eliminated when we disrupted the single feature orientation information in addition to the configural information, by using a new type of transformation similar to Thatcherizing our sets of scrambled faces. We conclude by noting that our results for scrambled faces are consistent with an account that has recognition performance entirely determined by the proportion of upright facial features within a stimulus, and that any ability to make use of the spatial configuration of these features seems to benefit upright and inverted normal faces alike.     

The perception of unfamiliar faces and houses by chimpanzees: influence of rotation angle

The inversion effect, or impaired recognition of upside-down faces, is used as evidence supporting the configural processing of faces. Human studies report a linear relationship between face-discrimination performance and orientation, such that recognition is more difficult as faces are rotated away from their typical viewpoint. Previous studies on chimpanzees also support a configural bias for processing faces, particularly faces for which subjects have developed expertise. In the present study, we examined the influence of expertise and rotation angle on the visual perception of faces in chimpanzees. Six subjects were presented with unaltered and blurred conspecific faces and houses in five orientation angles. A computerized paradigm was used to further delineate the nature of configural face processing in this species. The data were consistent with those reported in humans: chimpanzees showed a significant linear impairment when discriminating conspecific faces as they rotated away from their upright orientation. No inversion effect was observed for discriminations involving houses. Thus, chimpanzees, like humans, show a face-specific inversion effect that is linearly affected by angle of orientation, suggesting that their visual processing of faces is strongly influenced by the extraction of configural cues and closely resembles the perceptual strategies of humans.     

Losing face: impaired discrimination of featural and configural information in the mouth region of an inverted face

Given that all faces share the same set of features—two eyes, a nose, and a mouth—that are arranged in similar configuration, recognition of a specific face must depend on our ability to discern subtle differences in its featural and configural properties. An enduring question in the face-processing literature is whether featural or configural information plays a larger role in the recognition process. To address this question, the face dimensions task was designed, in which the featural and configural properties in the upper (eye) and lower (mouth) regions of a face were parametrically and independently manipulated. In a same–different task, two faces were sequentially presented and tested in their upright or in their inverted orientation. Inversion disrupted the perception of featural size (Exp. 1), featural shape (Exp. 2), and configural changes in the mouth region, but it had relatively little effect on the discrimination of featural size and shape and configural differences in the eye region. Inversion had little effect on the perception of information in the top and bottom halves of houses (Exp. 3), suggesting that the lower-half impairment was specific to faces. Spatial cueing to the mouth region eliminated the inversion effect (Exp. 4), suggesting that participants have a bias to attend to the eye region of an inverted face. The collective findings from these experiments suggest that inversion does not differentially impair featural or configural face perceptions, but rather impairs the perception of information in the mouth region of the face.     

Expert face coding: Configural and component coding of own-race and other-race faces

Configural and holistic coding are hallmarks of face perception. Although recent studies have shown that own-race faces are coded more holistically than other-race faces, the evidence for better configural coding of own-race faces is equivocal. We directly measured configural and component coding of own- and other-race male faces in Caucasian and Chinese participants. We manipulated individual features (components) or their spatial relations (configurations) using a novel morphing method to vary difficulty parametrically and tested sensitivity to these changes in a sequential matching task. Both configural and component coding were better for upright own-race than for upright other-race faces. Inversion impaired detection of configural changes more than it did detection of component changes, but also impaired performance more for easier discriminations,independent of type of change. These results challenge explanations of face expertise that rely solely on configural and holistic processing, and also call into question the widespread interpretation of large inversion decrements as diagnostic of configural coding.     

Understanding the role of configural processing in face emotion recognition in Parkinson’s disease

This investigation examined whether impairment in configural processing could explain deficits in face emotion recognition in people with Parkinson’s disease (PD). Stimuli from the Radboud Faces Database were used to compare recognition of four negative emotion expressions by older adults with PD (n = 16) and matched controls (n = 17). Participants were tasked with categorizing emotional expressions from upright and inverted whole faces and facial composites; it is difficult to derive configural information from these two types of stimuli so featural processing should play a larger than usual role in accurate recognition of emotional expressions. We found that the PD group were impaired relative to controls in recognizing anger, disgust and fearful expressions in upright faces. Then, consistent with a configural processing deficit, participants with PD showed no composite effect when attempting to identify facial expressions of anger, disgust and fear. A face inversion effect, however, was observed in the performance of all participants in both the whole faces and facial composites tasks. These findings can be explained in terms of a configural processing deficit if it is assumed that the disruption caused by facial composites was specific to configural processing, whereas inversion reduced performance by making it difficult to derive both featural and configural information from faces.     

Discrimination of faces and houses by rhesus monkeys: the role of stimulus expertise and rotation angle

The face inversion effect, or impaired recognition of upside down compared to upright faces, is used as a marker for the configural processing of faces in primates. The inversion effect in humans and chimpanzees is strongest for categories of stimuli for which subjects have considerable expertise, primarily conspecifics’ faces. Moreover, discrimination performance decreases linearly as faces are incrementally rotated from upright to inverted. This suggests that rotated faces must be transformed, or normalized back into their most typical viewpoint before configural processing can ensue, and the greater the required normalization, the greater the likelihood of errors resulting. Previous studies in our lab have demonstrated a general face inversion effect in rhesus monkeys that was not influenced by expertise. Therefore, the present study examined the influence of rotation angle on the visual perception of face and nonface stimuli that varied in their level of expertise to further delineate the processes underlying the inversion effect in rhesus monkeys. Five subjects discriminated images in five orientation angles. Results showed significant linear impairments for all stimulus categories, including houses. However, compared to the upright images, only rhesus faces resulted in worse performance at rotation angles greater than 45°, suggesting stronger configural processing for stimuli for which subjects had the greatest expertise.     

Effects of geometric distortions on face-recognition performance

The importance of 'configural' processing for face recognition is now well established, but it remains unclear precisely what it entails. Through four experiments we attempted to clarify the nature of configural processing by investigating the effects of various affine transformations on the recognition of familiar faces. Experiment 1 showed that recognition was markedly impaired by inversion of faces, somewhat impaired by shearing or horizontally stretching them, but unaffected by vertical stretching of faces to twice their normal height. In experiment 2 we investigated vertical and horizontal stretching in more detail, and found no effects of either transformation. Two further experiments were performed to determine whether participants were recognising stretched faces by using configural information. Experiment 3 showed that nonglobal vertical stretching of faces (stretching either the top or the bottom half while leaving the remainder undistorted) impaired recognition, implying that configural information from the stretched part of the face was influencing the process of recognition--ie that configural processing involves global facial properties. In experiment 4 we examined the effects of Gaussian blurring on recognition of undistorted and vertically stretched faces. Faces remained recognisable even when they were both stretched and blurred, implying that participants were basing their judgments on configural information from these stimuli, rather than resorting to some strategy based on local featural details. The tolerance of spatial distortions in human face recognition suggests that the configural information used as a basis for face recognition is unlikely to involve information about the absolute position of facial features relative to each other, at least not in any simple way.     

Faces elicit different scanning patterns depending on task demands

Eye movements were recorded while participants discriminated upright and inverted faces that differed with respect to either configural or featural information. Two hypotheses were examined: (1) whether featural and configural information processing elicit different scanning patterns; (2) whether fixations on a specific region of the face dominate scanning patterns. Results from two experiments were compared to examine whether participants’ prior knowledge of the kind of information that would be relevant for the task (i.e., configural vs featural) influences eye movements. In Experiment 1, featural and configural discrimination trials were presented in random order such that participants were unaware of the information that would be relevant on any given trial. In Experiment 2, featural and configural discrimination trials were blocked and participants were informed of the nature of the discriminations. The results of both experiments suggest that faces elicit different scanning patterns depending on task demands. When participants were unaware of the nature of the information relevant for the task at hand, face processing was dominated by attention to the eyes. When participants were aware that relational information was relevant, scanning was dominated by fixations to the center of the face. We conclude that faces elicit scanning strategies that are driven by task demands.     

Effects of geometric distortions,Gaussian blur,and contrast negation on recognition of familiar faces

It is assumed that “configural processing” is important for recognizing people whom we know. Studies have shown better discrimination of relational changes between facial features when faces are presented upright than upside down and when presented as photographic negatives. However, studies have also demonstrated tolerance for complex changes to facial configuration of familiar faces when images are geometrically distorted. In two experiments, we explored effects of linear stretching, Gaussian blur, and contrast negation on recognition of familiar or unfamiliar faces (Experiment 1) and familiar or unfamiliar company brand logos (Experiment 2). Only contrast negation severely impaired recognition of familiar faces but not unfamiliar faces or company brand logos. Effects of contrast negation were additional to linear stretching, whereas linear stretching independently had no impact on recognition. These findings highlight an important deficit in the recognition of familiar faces caused by contrast negation.     

Normal perception of Mooney faces in developmental prosopagnosia: Evidence from the N170 component and rapid neural adaptation

Individuals with developmental prosopagnosia (DP) have a severe difficulty recognizing the faces of known individuals in the absence of any history of neurological damage. These recognition problems may be linked to selective deficits in the holistic/configural processing of faces. We used two‐tone Mooney images to study the processing of faces versus non‐face objects in DP when it is based on holistic information (or the facial gestalt) in the absence of obvious local cues about facial features. A rapid adaptation procedure was employed for a group of 16 DPs. Naturalistic photographs of upright faces were preceded by upright or inverted Mooney faces or by Mooney houses. DPs showed face‐sensitive N170 components in response to Mooney faces versus houses, and N170 amplitude reductions for inverted as compared to upright Mooney faces. They also showed the typical pattern of N170 adaptation effects, with reduced N170 components when upright naturalistic test faces were preceded by upright Mooney faces, demonstrating that the perception of Mooney and naturalistic faces recruits shared neural populations. Our findings demonstrate that individuals with DP can utilize global information about face configurations for categorical discriminations between faces and non‐face objects, and suggest that face processing deficits emerge primarily at more fine‐grained higher level stages of face perception.     

Faces as perceptual wholes: The interplay between component and configural properties in face processing

The relative dominance of component and configural properties in face processing is a controversial issue. We examined this issue by testing whether the discriminability of components predicts the discrimination of faces with similar versus dissimilar configurations. Discrimination of faces with similar configurations was determined by components discriminability, indicating independent processing of facial components. The presence of configural variation had no effect on discriminating faces with highly discriminable components, suggesting that discrimination was based on the components. The presence of configural variation, however, facilitated the discrimination of faces with more difficult-to-discriminate components, above and beyond what would be predicted by the configural or componential discriminability, indicating interactive processing. No effect of configural variation was observed in discriminating inverted faces. These results suggest that both component and configural properties contribute to the processing of upright faces and no property necessarily dominates the other. Upright face discrimination can rely on components, configural properties, or interactive processing of component and configural properties, depending on the information available and the discriminability of the properties. Inverted faces are dominated by componential processing. The finding that interactive processing of component and configural properties surfaced when the properties were of similar, not very high discriminability, suggests that such interactive processing may be the dominant form of face processing in everyday life.     

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.     

Features are also important: contributions of featural and configural processing to face recognition

It has been suggested that face recognition is primarily based on configural information, with featural information playing little or no role. We investigated this idea by comparing the prototype effect for face prototypes that emphasized either featural or configural processing. In Experiment 1, participants showed a tendency to commit false alarms in response to nonstudied prototypes, and this tendency was equivalent for featural and configural prototypes. Experiment 2 replicated this finding, and provided support for the assumption that the two types of prototypes differed in terms of featural and configural processing: Face inversion eliminated the prototype effect for configural prototypes but not for featural prototypes. These results suggest that both featural and configural processing make important contributions to face recognition, and that their effects are dissociable.