The role of surface pigmentation for recognition revealed by contrast reversal in faces and Greebles

Vuong, Quoc C.; Peissig, Jessie J.; Harrison, Marianne C.; Tarr, Michael J.

doi:10.1016/j.visres.2004.11.015

Cited by 78 publications

(59 citation statements)

References 26 publications

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“…This pattern of contrastrelated N170 modulations in the Control group shows that contrast signals from the eye region play a special role during the structural encoding of faces. Inverting the contrast of face images generally impairs the processing of information that can be extracted from three-dimensional shape-from-shading cues (Johnston et al, 1992;Lui, Collins, & Chaudhuri, 2000) and from the surface reflectance properties of face texture and pigmentation (Russell, Sinha, Biedermann, & Nederhouser, 2006;Vuong, Peissig, Harrison, & Tarr, 2005). Because the eye region contains several important contrast-related signals (e.g.…”

Section: Discussionmentioning

confidence: 99%

Reduced sensitivity to contrast signals from the eye region in developmental prosopagnosia

Fisher

Towler

Eimer

2016

Cortex

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Contrast-related signals from the eye region are known to be important for the processing of facial identity. Individuals with developmental prosopagnosia (DP) have severe face recognition problems, which may be linked to deficits in the perceptual processing of identity-related information from the eyes. We tested this hypothesis by measuring N170 components in DP participants and age-matched controls in response to face images where the contrast polarity of the eyes and of other face parts was independently manipulated. In different trials, participants fixated either the eye region or the lower part of a face. In the Control group, contrast-reversal of the eyes resulted in enhanced and delayed N170 components, irrespective of the contrast of other face parts and of gaze location. In the DP group, these effects of eye contrast on N170 amplitudes were strongly and significantly reduced, demonstrating that perceptual face processing in DP is less well tuned to contrast information from the eye region. Inverting the contrast of other parts of the face affected N170 amplitudes only when fixation was outside the eye region. This effect did not differ between the two groups, indicating that DPs are not generally insensitive to the contrast polarity of face images. These results provide new evidence that a selective deficit in detecting and analysing identity-related information provided by contrast signals from the eye region may contribute to the face recognition impairment in DP.

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Section: Discussionmentioning

confidence: 99%

Reduced sensitivity to contrast signals from the eye region in developmental prosopagnosia

Fisher

Towler

Eimer

2016

Cortex

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“…One explanation of the photographic-negative effect relates to disruption in the processing of pigmentation (e.g., Bruce & Langton, 1994;Hole et al, 1999;Russell et al, 2006;Vuong et al, 2005), such as when the colour of hair and eyes are altered. Negation may also interfere with the pattern of shading across a face (e.g.…”

Section: Photographic Negationmentioning

confidence: 99%

“…Johnston, Hill & Carman, 1992). There is an interaction between the shape of the face and direction of lighting (Russell et al, 2006;Vuong et al, 2005), known as shape-from-shading relations, which can be used to estimate the three-dimensional structure of a face (Phillips, 1971); irregular patterns of shading (with negation) can impair formation of this mental representation (Hill & Bruce, 1996). It is even possible that negation may interfere with global processing of the face.…”

Section: Photographic Negationmentioning

confidence: 99%

Configural and featural information in facial-composite images

et al. 2014

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(6) Scientific Support Lancashire Constabulary, PR4 5SB (7) Department of Psychology University of Stirling, FK9 4LA 2 Eyewitnesses are often invited to construct a facial composite, an image created of the person they saw commit a crime that is used by law enforcement to locate criminal suspects. In the current paper, the effectiveness of composite images was investigated from traditional feature systems (E-FIT and PRO-fit), where participants (face constructors) selected individual features to build the face, and a more recent holistic system (EvoFIT), where they 'evolved' a composite by repeatedly selecting from arrays of complete faces. Further participants attempted to name these composites when seen as an unaltered image, or when blurred, rotated, linearly stretched or converted to a photographic negative. All of the manipulations tested reduced correct naming of the composites overall except (i) for a low level of blur, for which naming improved for holistic composites but reduced for feature composites, and (ii) for 100% linear stretch, for which a substantial naming advantage was observed. Results also indicated that both featural (facial elements) and configural (feature spacing) information was useful for recognition in both types of composite system, but highly-detailed information was more accurate in the feature-based than the holistic method. The naming advantage of linear stretch was replicated using a forensically more-practical procedure with observers viewing an unaltered composite sideways. The work is valuable to police practitioners and designers of facial-composite systems. The research investigates the effectiveness of facial-composite systems as used by police practitioners to locate people (offenders) who commit crime. It is found that different types of information were created differently for contrasting composite systems. A novel presentation format was also developed that should substantially improve recognition of real-world composites.(50 words.) 3

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“…Although plausible, it is unclear whether this explanation is a sufficient one, especially in light of experimental results showing preserved recognition performance in the absence of shading gradients (12), and theories of face recognition that are based on the use of 2D intensity patterns rather than recovered 3D shapes (13,14). Another prominent hypothesis is that negation causes faces to have unusual pigmentation (15,16). However, the adequacy of this ''pigmentation hypothesis'' has been challenged by data showing that hue negation, which also results in unnatural pigmentation (making the entire face look bluish-green), has little effect on recognition performance (11).…”

mentioning

confidence: 99%

Role of ordinal contrast relationships in face encoding

Gilad

Meng²,

Sinha³

2009

Proc. Natl. Acad. Sci. U.S.A.

116

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What aspects of facial information do we use to recognize individuals? One way to address this fundamental question is to study image transformations that compromise facial recognizability. The goal would be to identify factors that underlie the recognition decrement and, by extension, are likely constituents of facial encoding. To this end, we focus here on the contrast negation transformation. Contrast negated faces are remarkably difficult to recognize for reasons that are currently unclear. The dominant proposals so far are based either on negative faces' seemingly unusual pigmentation, or incorrectly computed 3D shape. Both of these explanations have been challenged by recent results. Here, we propose an alternative account based on 2D ordinal relationships, which encode local contrast polarity between a few regions of the face. Using a novel set of facial stimuli that incorporate both positive and negative contrast, we demonstrate that ordinal relationships around the eyes are major determinants of facial recognizability. Our behavioral studies suggest that destruction of these relationships in negatives likely underlies the observed recognition impairments, and our neuro-imaging data show that these relationships strongly modulate brain responses to facial images. Besides offering a potential explanation for why negative faces are hard to recognize, these results have implications for the representational vocabulary the visual system uses to encode faces.contrast negation ͉ face perception ͉ fMRI ͉ neural representation ͉ object recognition I n principle, a contrast negated image is exactly as informative as its positive counterpart; negation perfectly preserves an image's 2D geometric and spectral structure. However, as anyone who has had to search through a roll of negatives for a snapshot of a particular person knows, this simple operation has dramatically adverse consequences on our ability to identify faces, as illustrated in Fig. 1 (1-6). Exploring the causes of this phenomenon is important for understanding the broader issue of the nature of information the visual system uses for face identification.Several researchers have hypothesized that negated face-images are hard to recognize because of the unnatural shading cues in negatives, which compromise shape from shading processes (7-11). The resulting problems in recovering veridical 3D facial shape are believed to impair recognition performance. Although plausible, it is unclear whether this explanation is a sufficient one, especially in light of experimental results showing preserved recognition performance in the absence of shading gradients (12), and theories of face recognition that are based on the use of 2D intensity patterns rather than recovered 3D shapes (13,14). Another prominent hypothesis is that negation causes faces to have unusual pigmentation (15, 16). However, the adequacy of this ''pigmentation hypothesis'' has been challenged by data showing that hue negation, which also results in unnatural pigmentation (making the entire face l...

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The role of surface pigmentation for recognition revealed by contrast reversal in faces and Greebles

Cited by 78 publications

References 26 publications

Reduced sensitivity to contrast signals from the eye region in developmental prosopagnosia

Reduced sensitivity to contrast signals from the eye region in developmental prosopagnosia

Configural and featural information in facial-composite images

Role of ordinal contrast relationships in face encoding

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