The sizable difficulty in matching unfamiliar faces differing only moderately in orientation in depth is a function of image dissimilarity.

Attempting to match unfamiliar, highly similar faces at moderate differences in orientation in depth is surprisingly difficult. No neurocomputational account of these costs that addressed the representation of faces by which a face-similarity metric can be derived has been offered. A metric specifying the similarity of the to-be-distinguished faces is required as the rotation costs will be a function of the difficulty in distinguishing the faces.

Vision: A Product of a Society of Independent Experts.

A lesion of primary visual cortex, V1, can result in the perceived size of objects varying with the size of their retinal image. A new study shows that the pregrasp span of the hand of an individual with such a lesion remains tuned to the object's true size, providing evidence for separate representations mediating perceptual appearance and motor interactions.

Visual noise consisting of X-junctions has only a minimal adverse effect on object recognition.

In 1968, Guzman showed that the myriad of surfaces composing a highly complex and novel assemblage of volumes can readily be assigned to their appropriate volumes in terms of the constraints offered by the vertices of coterminating edges. Of particular importance was the L-vertex, produced by the cotermination of two contours, which provides strong evidence for the termination of a 2-D surface. An X-junction, formed by the crossing of two contours without a change of direction at the crossing, played no role in the segmentation of a scene.

Pigeons spontaneously form three-dimensional shape categories.

We explored the pigeon's representation of the shape of simple three-dimensional objects (geons) rotated in depth (four views each of four geons). Pigeons assigned to the Categorization group had to respond differentially to images of four different geons-termed arch, barrel, brick, and wedge-based on their 3D shape, regardless of the orientation of the object. Pigeons assigned to the Pseudocategorization group had to respond differentially to the same objects based on groupings that did not correspond to object identity, which required the learning of local orientation-dependent features (e.

A face in a (temporal) crowd.

Familiar objects, specified by name, can be identified with high accuracy when embedded in a rapidly presented sequence of images at rates exceeding 10 images/s. Not only can target objects be detected at such brief presentation rates, they can also be detected under high uncertainty, where their classification is defined negatively, e.g.

The cognitive neuroscience of person identification.

We compare and contrast five differences between person identification by voice and face. 1. There is little or no cost when a familiar face is to be recognized from an unrestricted set of possible faces, even at Rapid Serial Visual Presentation (RSVP) rates, but the accuracy of familiar voice recognition declines precipitously when the set of possible speakers is increased from one to a mere handful.

What Is Actually Affected by the Scrambling of Objects When Localizing the Lateral Occipital Complex?

The lateral occipital complex (LOC), the cortical region critical for shape perception, is localized with fMRI by its greater BOLD activity when viewing intact objects compared with their scrambled versions (resembling texture). Despite hundreds of studies investigating LOC, what the LOC localizer accomplishes-beyond distinguishing shape from texture-has never been resolved. By independently scattering the intact parts of objects, the axis structure defining the relations between parts was no longer defined.

The Neural Correlates of Humor Creativity.

Unlike passive humor appreciation, the neural correlates of real-time humor creation have been unexplored. As a case study for creativity, humor generation uniquely affords a reliable assessment of a creative product's quality with a clear and relatively rapid beginning and end, rendering it amenable to neuroimaging that has the potential for reflecting individual differences in expertise. Professional and amateur "improv" comedians and controls viewed New Yorker cartoon drawings while being scanned.

The Lateral Occipital Complex shows no net response to object familiarity.

In 1995, Malach et al. discovered an area whose fMRI BOLD response was greater when viewing intact, familiar objects than when viewing their scrambled versions (resembling texture). Since then hundreds of studies have explored this late visual region termed the Lateral Occipital Complex (LOC), which is now known to be critical for shape perception (James, Culham, Humphrey, Milner, & Goodale, 2003).

An applet for the Gabor similarity scaling of the differences between complex stimuli.

It is widely accepted that after the first cortical visual area, V1, a series of stages achieves a representation of complex shapes, such as faces and objects, so that they can be understood and recognized. A major challenge for the study of complex shape perception has been the lack of a principled basis for scaling of the physical differences between stimuli so that their similarity can be specified, unconfounded by early-stage differences. Without the specification of such similarities, it is difficult to make sound inferences about the contributions of later stages to neural activity or psychophysical performance.

Effective signaling of surface boundaries by L-vertices reflect the consistency of their contrast in natural images.

An L-vertex, the point at which two contours coterminate, provides highly reliable evidence that a surface terminates at that vertex, thus providing the strongest constraint on the extraction of shape from images (Guzman, 1968). Such vertices are pervasive in our visual world but the importance of a statistical regularity about them has been underappreciated: The contours defining the vertex are (almost) always of the same direction of contrast with respect to the background (i.e.

An estimate of the prevalence of developmental phonagnosia.

A web-based survey estimated the distribution of voice recognition abilities with a focus on determining the prevalence of developmental phonagnosia, the inability to identify a familiar person based on their voice. Participants matched clips of 50 celebrity voices to 1-4 named headshots of celebrities whose voices they had previously rated for familiarity. Given a strong correlation between rated familiarity and recognition performance, a residual was calculated based on the average familiarity rating on each trial, which thus constituted each respondent's voice recognition ability that could not be accounted for by familiarity.

Developmental phonagnosia: Neural correlates and a behavioral marker.

A 20-year old female, AN, with no history of neurological events or detectable lesions, was markedly poorer than controls at identifying her most familiar celebrity voices. She was normal at face recognition and in discriminating which of two speakers uttered a particular sentence. She evidences normal fMRI sensitivity for human speech and non-speech sounds.

Using the reassignment procedure to test object representation in pigeons and people.

In four experiments, we evaluated Lea's (1984) reassignment procedure for studying object representation in pigeons (Experiments 1-3) and humans (Experiment 4). In the initial phase of Experiment 1, pigeons were taught to make discriminative button responses to five views of each of four objects. Using the same set of buttons in the second phase, one view of each object was trained to a different button.

A neurocomputational account of the face configural effect.

A striking phenomenon in face perception is the configural effect in which a difference in a single part appears more distinct in the context of a face than it does by itself. The face context would be expected to increase search complexity, rendering discrimination more--not less--difficult. Remarkably, there has never been a biologically plausible explanation of this fundamental signature of face recognition.

Greater sensitivity to nonaccidental than metric shape properties in preschool children.

Nonaccidental properties (NAPs) are image properties that are invariant over orientation in depth and allow facile recognition of objects at varied orientations. NAPs are distinguished from metric properties (MPs) that generally vary continuously with changes in orientation in depth. While a number of studies have demonstrated greater sensitivity to NAPs in human adults, pigeons, and macaque IT cells, the few studies that investigated sensitivities in preschool children did not find significantly greater sensitivity to NAPs.

Ha ha! versus aha! a direct comparison of humor to nonhumorous insight for determining the neural correlates of mirth.

While humor typically involves a surprising discovery, not all discoveries are perceived as humorous or lead to a feeling of mirth. Is there a difference in the neural signature of humorous versus nonhumorous discovery? Subjects viewed drawings that were uninterpretable until a caption was presented that provided either: 1) a nonhumorous interpretation (or insight) of an object from an unusual or partial view (UV) or 2) a humorous interpretation (HU) of the image achieved by linking remote and unexpected concepts. fMRI activation elicited by the UV captions was a subset of that elicited by the humorous HU captions, with only the latter showing activity in the temporal poles and temporo-occipital junction (linking remote concepts), and medial prefrontal cortex (unexpected reward).

Neural correlates of face detection.

Although face detection likely played an essential adaptive role in our evolutionary past and in contemporary social interactions, there have been few rigorous studies investigating its neural correlates. MJH, a prosopagnosic with bilateral lesions to the ventral temporal-occipital cortices encompassing the posterior face areas (fusiform and occipital face areas), expresses no subjective difficulty in face detection, suggesting that these posterior face areas do not mediate face detection exclusively. Despite his normal contrast sensitivity and visual acuity in foveal vision, the present study nevertheless revealed significant face detection deficits in MJH.

Greater sensitivity to nonaccidental than metric changes in the relations between simple shapes in the lateral occipital cortex.

Behavioral studies and single cell recordings in monkey inferotemporal cortex have documented greater sensitivity to differences in viewpoint invariant or nonaccidental properties (e.g., straight vs.

Sensitivity to nonaccidental properties across various shape dimensions.

Nonaccidental properties (NAPs) are image properties that are invariant over orientation in depth and are distinguished from metric properties (MPs) that can change continuously with variations over depth orientation. To a large extent NAPs allow facile recognition of objects at novel viewpoints. Two match-to-sample experiments with 2D or 3D appearing geons assessed sensitivity to NAP vs.

Cortical representation of medial axis structure.

The identity of an object is not only specified by its parts but also by the relations among the parts. Rearranging parts can produce a completely different object, in the same manner as rearranging the phonemes in "fur" can yield "rough." How does the visual system represent the relative positions of parts? Between-part relations can be characterized by specifying the relations between the medial axes (imaginary lines through the centers) of an object's parts.

Predicting the psychophysical similarity of faces and non-face complex shapes by image-based measures.

Shape representation is accomplished by a series of cortical stages in which cells in the first stage (V1) have local receptive fields tuned to contrast at a particular scale and orientation, each well modeled as a Gabor filter. In succeeding stages, the representation becomes largely invariant to Gabor coding (Kobatake & Tanaka, 1994). Because of the non-Gabor tuning in these later stages, which must be engaged for a behavioral response (Tong, 2003; Tong et al.

The neural basis for shape preferences.

Several dimensions of shape, such as curvature or taper, can be regarded as extending from a singular (S) or 0 value (e.g., a straight contour with 0 curvature or parallel contours with a 0 angle of convergence) to an infinity of non-singular (NS) values (e.

The benefit of object interactions arises in the lateral occipital cortex independent of attentional modulation from the intraparietal sulcus: a transcranial magnetic stimulation study.

Our visual experience is generally not of isolated objects, but of scenes, where multiple objects are interacting. Such interactions (e.g.

Neural encoding of relative position.

Late ventral visual areas generally consist of cells having a significant degree of translation invariance. Such a "bag of features" representation is useful for the recognition of individual objects; however, it seems unable to explain our ability to parse a scene into multiple objects and to understand their spatial relationships. We review several schemes (e.