Judging egocentric distance on the ground: occlusion and surface integration

On the basis of the finding that a common and homogeneous ground surface is vital for accurate egocentric distance judgments (Sinai et al, 1998 Nature 395 497-500), we propose a sequential-surface-integration-process (SSIP) hypothesis to elucidate how the visual system constructs a representation of the ground-surface in the intermediate distance range. According to the SSIP hypothesis, a near ground-surface representation is formed from near depth cues, and is utilized as an anchor to integrate the more distant surfaces by using texture-gradient information as the depth cue. The SSIP hypothesis provides an explanation for the finding that egocentric distance judgment is underestimated when a texture boundary exists on the ground surface that commonly supports the observer and target. We tested the prediction that the fidelity of the visually represented ground-surface reference frame depends on how the visual system selects the surface information for integration. Specifically, if information is selected along a direct route between the observer and target where the ground surface is disrupted by an occluding object, the ground surface will be inaccurately represented. In experiments 1-3 we used a perceptual task and two different visually directed tasks to show that this leads to egocentric distance underestimation. Judgment is accurate however, when the observer selects the continuous ground information bypassing the occluding object (indirect route), as found in experiments 4 and 5 with a visually directed task. Altogether, our findings provide support for the SSIP hypothesis and reveal, surprisingly, that the phenomenal visual space is not unique but depends on how optic information is selected.     

Early computation of part structure: evidence from visual search

The visual system represents object shapes in terms of intermediate-level parts. The minima rule proposes that the visual system uses negative minima of curvature to define boundaries between parts. We used visual search to test whether part structures consistent with the minima rule are computed preattentively--or at least, rapidly and early in visual processing. The results of Experiments 1 and 2 showed that whereas the search for a non-minima-segmented shape is fast and efficient among minima-segmented shapes, the reverse search is slow and inefficient. This asymmetry is expected if parsing at negative minima occurs obligatorily. The results of Experiments 3 and 4 showed that although both minima- and non-minima-segmented shapes pop out among unsegmented shapes, the search for minima-segmented shapes is significantly slower. Together, these results demonstrate that the visual system segments shapes into parts, using negative minima of curvature, and that it does so rapidly in early stages of visual processing.     

Asymmetry in 3-D perceptual organization: ground-like surface superior to ceiling-like surface

Attneave (1954) and Barlow (1961) proposed that the visual system might increase efficiency of representation by preferentially encoding spatiotemporally redundant patterns of the external world. The present experiments tested the application of this principle to three-dimensional (3-D) perceptual organization, capitalizing on the ecological constraint that human observers must frequently interact with objects arranged on the ground or on a surface parallel to it (Gibson, 1950). Observers performed a task that required them to perceptually segregate and search multiple items distributed in depth and embedded within a larger, 3-D array of distractors. Stimulus displays were organized to globally recede top-away in depth, as if attached to an underlying ground-like surface, or bottom-away, as if attached to an overhanging ceiling-like surface; ground-like and ceiling-like displays differed only in the direction of disparity gradient within the displays. Primary findings revealed superior performance with ground-like displays, suggesting that spatially and stereoscopically distributed items are more easily organized to represent an ecologically representative pattern, even when no inherent physical regularities favor that pattern.     

Visual motion and the human brain: what has neuroimaging told us?

Recently, neuroimaging techniques have been applied to the study of human motion perception, complementing established techniques such as psychophysics, neurophysiology and neuropsychology. Because vision, particularly motion perception, has been studied relatively extensively, it provides an interesting case study to examine the contributions and limitations of neuroimaging to cognitive neuroscience. We suggest that in the domain of motion perception neuroimaging has: (1) revealed an extensive network of motion areas throughout the human brain, in addition to the well-studied motion complex (MT+); (2) verified and extended findings from other techniques; (3) suggested extensive top-down influences on motion perception; and (4) allowed experimenters to examine the neural correlates of awareness. We discuss these contributions, along with limitations and future directions for the neuroimaging of motion.     

Sequential priming of 3-D perceptual organization

In four experiments, the effects of sequential priming on the perceptual organization of complex three-dimensional (3-D) displays were examined. Observers were asked to view stereoscopic arrays and to search an embedded subset of items for an odd-colored target while 3-D orientation of the stimuli was varied randomly between trials. Search times decreased reliably when 3-D stimulus orientation was unchanged on consecutive trials, indicating substantial sequential priming by 3-D stimulus layout. The priming was nonsensory and was independent of priming by additional stimulus characteristics. Finally, priming by 3-D layout was unaffected by observers' foreknowledge of display orientation. Results indicate that perceptual organization of 3-D stimuli is guided by a short-term trace of 3-D spatial relationships between stimuli.     

江西云居山佛教史话述略

中国汉地佛教经北周灭佛和隋唐之际的战乱,以长安、洛阳、邺都为中心的中原地带,发生过一南一北两次大规模的僧众流动。其中向南一支广布于淮南江表诸郡和荆襄地区,日益发达,最终成为禅宗的发详地。其标志是初唐道信和法融两支禅系的崛起。     

残疾人大学生领悟社会支持对主观幸福感的影响:自我同情的中介作用

探讨残疾人大学生领悟社会支持、自我同情与主观幸福感的关系。采用领悟社会支持量表、幸福感指数量表、大学生自我同情量表对普通高等特殊教育学校206名在校残疾人大学生进行了调查研究。结果表明:(1)残疾人大学生领悟社会支持与自我同情存在显著正相关,与主观幸福感存在显著正相关; 自我同情与主观幸福感存在显著正相关。(2)残疾人大学生领悟社会支持不能直接预测主观幸福感,但通过自我同情的中介作用间接预测主观幸福感。自我同情在残疾人大学生领悟社会支持与主观幸福感的关系中起完全中介作用。     

Gray Matter Atrophy in the Cortico-Striatal-Thalamic Network and Sensorimotor Network in Relapsing–Remitting and Primary Progressive Multiple Sclerosis

Neuropsychology Review - Gray matter atrophy in multiple sclerosis (MS) is thought to be associated with disability and cognitive impairment, but previous studies have sometimes had discordant...     

Correction to: Gray Matter Atrophy in the Cortico‑Striatal‑Thalamic Network and Sensorimotor Network in Relapsing–Remitting and Primary Progressive Multiple Sclerosis

Neuropsychology Review - A correction to this paper has been published: https://doi.org/10.1007/s11065-021-09503-6     

Childhood Trauma and Self-Control: The Mediating Role of Depletion Sensitivity

Journal of Child and Family Studies - Previous research demonstrated that childhood trauma was associated with self-control deficit from adolescence to adulthood. However, the underlying mechanism...