Publications by authors named "Cavanagh P"

Backward masking is a powerful phenomenon that can reduce, often to zero, the visibility of targets. Here, we show that when the masking is less than completely effective so that the target remains visible, the masking has other effects, specifically reducing the perceived size of the target.

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A rotating stimulus of alternating red and white sectors generates a faint pink fill throughout the image. The trailing cyan after images of the red sectors quickly become the brightest regions in the image, providing an index of the overall illumination that triggers a shift of the white point. Actual white areas then shift in the opposite direction and appear pink.

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The perception of an object's location is profoundly influenced by the surrounding dynamics. This is dramatically demonstrated by the frame effect, where a moving frame induces substantial shifts in the perceived location of objects that flash within it. In this study, we examined the elements contributing to the large magnitude of this effect.

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Motion can produce large changes in the apparent locations of briefly flashed tests presented on or near the motion. These motion-induced position shifts may have a variety of sources. They may be due to a frame effect where the moving pattern provides a frame of reference for the locations of events within it.

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Taurine is a conditionally essential micronutrient and one of the most abundant amino acids in humans. In endogenous taurine metabolism, dedicated enzymes are involved in the biosynthesis of taurine from cysteine and in the downstream metabolism of secondary taurine metabolites. One taurine metabolite is N-acetyltaurine.

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Moving frames produce large displacements in the perceived location of flashed and continuously moving probes. In a series of experiments, we test the contributions of the probe's displacement and the frame's displacement on the strength of the frame's effect. In the first experiment, we find a dramatic position shift of flashed probes whereas the effect on a continuously moving probe is only one-third as strong.

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Everybody loves illusions. At times, the content on the internet seems to be mostly about illusions-shoes, dresses, straight lines looking bent. This attraction has a long history.

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Crowding and the word superiority effect are two perceptual phenomena that influence reading. The identification of the inner letters of a word can be hindered by crowding from adjacent letters, but it can be facilitated by the word context itself (the word superiority effect). In the present study, strings of four-letters (words and non-words) with different inter-letter spacings (ranging from an optimal spacing to produce crowding to a spacing too large to produce crowding) were presented briefly in the periphery and participants were asked to identify the third letter of the string.

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Taurine is a conditionally essential micronutrient and one of the most abundant amino acids in humans. In endogenous taurine metabolism, dedicated enzymes are involved in biosynthesis of taurine from cysteine as well as the downstream derivatization of taurine into secondary taurine metabolites. One such taurine metabolite is N-acetyltaurine.

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The ability to accurately perceive and track moving objects is crucial for many everyday activities. In this study, we use a "double-drift stimulus" to explore the processing of visual motion signals that underlie perception, pursuit, and saccade responses to a moving object. Participants were presented with peripheral moving apertures filled with noise that either drifted orthogonally to the aperture's direction or had no net motion.

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Individuals with diabetes are at a higher risk of developing foot ulcers. To better understand internal soft tissue loading and potential treatment options, subject-specific finite element (FE) foot models have been used. However, existing models typically lack subject-specific soft tissue material properties and only utilize subject-specific anatomy.

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When a stationary target is briefly presented on top of a moving background as it reverses direction, the target is displaced perceptually in the direction of the upcoming motion (the flash grab effect). To determine the role of attention in this effect, we investigated whether the predictability of the location of the flash grab target modulates the illusion. First, we established that effect was weaker for spatially predictable targets.

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Equiluminant stimuli help assess the integrity of colour perception and the relationship of colour to other visual features. As a result of individual variation, it is necessary to calibrate experimental visual stimuli to suit each individual's unique equiluminant ratio. Most traditional methods rely on training observers to report their subjective equiluminance point.

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Motion, position, and form are intricately intertwined in perception. Motion distorts visual space, resulting in illusory position shifts such as flash-drag and flash-grab effects. The flash-grab displaces a test by up to several times its size.

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The double-drift illusion has two unique characteristics: The error between the perceived and physical position of the stimulus grows over time, and saccades to the moving target land much closer to the physical than the perceived location. These results suggest that the perceptual and saccade targeting systems integrate visual information over different time scales. Functional imaging studies in humans have revealed several potential cortical areas of interest, including the prefrontal cortex.

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For more than 2000 years, artists have exploited cast shadows to influence how objects appear to be positioned in a scene. A contact cast shadow can anchor an object to the ground and a detached cast shadow can make an object appear to float. However, there is a period of approximately 1000 years when there were virtually no cast shadows in art.

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Ambiguous patterns have a tendency to appear to point up. This bias makes sense as most objects are on the ground, pointing up. However, we discover that the source of the up bias is the preference for seeing depth receding from the lower to the upper visual field.

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The expected color of an object influences how it is perceived. For example, a banana in a greyscale photo may appear slightly yellow because bananas are expected to be yellow. This phenomenon is known as the memory color effect (MCE), and the objects with a memory color are called "color-diagnostic.

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The allocation of attention to objects raises several intriguing questions: What are objects, how does attention access them, what anatomical regions are involved? Here, we review recent progress in the field to determine the mechanisms underlying object-based attention. First, findings from unconscious priming and cueing suggest that the preattentive targets of object-based attention can be fully developed object representations that have reached the level of identity. Next, the control of object-based attention appears to come from ventral visual areas specialized in object analysis that project downward to early visual areas.

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Two versions of the flash grab illusion were used to examine the relative contributions of motion before and motion after the test flash to the illusory position shift. The stimulus in the first two experiments was a square pattern that expanded and contracted with an outline square flashed each time the motion reversed producing a dramatic difference in perceived size between the two reversals. Experiment 1 showed a strong illusion when motion was present before and after the flashed tests or just after the flashes, but no significant effect when only the pre-flash motion was present.

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When two pre-existing, separated squares are connected by the sudden onset of a bar between them, viewers do not perceive the bar to appear all at once. Instead, they see an illusory morphing of the original squares over time. The direction of this transformational apparent motion (TAM) can be influenced by endogenous attention deployed before the appearance of the connecting bar.

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Probes flashed within a moving frame are dramatically displaced (Özkan, Anstis, 't Hart, Wexler, & Cavanagh, 2021; Wong & Mack, 1981). The effect is much larger than that seen on static or moving probes (induced motion, Duncker, 1929; Wallach, Bacon, & Schulman, 1978). These flashed probes are often perceived with the separation they have in frame coordinates-a 100% effect (Özkan et al.

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An unusual arsenate mineral, mansfieldite (AlAsO·2HO), was identified as a pigment for the first time as the principal white colorant on two Himalayan thangka paintings at the Indianapolis Museum of Art at Newfields. The co-occurrence of this unusual mineral pigment provides support for the belief that the two artworks are members of a cycle of paintings originating from the same workshop, perhaps from Chamdo, Tibet. The complete palettes of both artworks are identical, including the use of mansfieldite, brochantite, malachite, azurite, vermilion, gold, orpiment, and a carbon-based black in a glue binder on a calcite and gypsum-primed cotton fabric.

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