室内照度和时间对警觉性和视空绩效的影响

本研究考察了白天室内照度和测验时间对个体视空工作记忆和视空能力及主观情绪和警觉性的影响。采用2(高/低照度水平)×2(上午/下午)混合设计,结果发现：被试在高照度水平下的柯西块任务的正确率更高,警觉反应更快,且尤其体现在下午时段;而不同照度水平对点记忆任务、视空能力测验和主观情绪无显著影响。结果表明白天室内照度能够影响个体的视空工作记忆和警觉性,主要表现在高照度照明环境的积极作用上,而对个体的视空能力及情绪变化影响微弱。     

Affective and cognitive reactions to subliminal flicker from fluorescent lighting

This study renews the classical concept of subliminal perception (Peirce & Jastrow, 1884) by investigating the impact of subliminal flicker from fluorescent lighting on affect and cognitive performance. It was predicted that low compared to high frequency lighting (latter compared to former emits non-flickering light) would evoke larger changes in affective states and also impair cognitive performance. Subjects reported high rather than low frequency lighting to be more pleasant, which, in turn, enhanced their problem solving performance. This suggests that sensory processing can take place outside of conscious awareness resulting in conscious emotional consequences; indicating a role of affect in subliminal/implicit perception, and that positive affect may facilitate cognitive task performance.     

What aspects of vision facilitate haptic processing?

We investigate how vision affects haptic performance when task-relevant visual cues are reduced or excluded. The task was to remember the spatial location of six landmarks that were explored by touch in a tactile map. Here, we use specially designed spectacles that simulate residual peripheral vision, tunnel vision, diffuse light perception, and total blindness. Results for target locations differed, suggesting additional effects from adjacent touch cues. These are discussed. Touch with full vision was most accurate, as expected. Peripheral and tunnel vision, which reduce visuo-spatial cues, differed in error pattern. Both were less accurate than full vision, and significantly more accurate than touch with diffuse light perception, and touch alone. The important finding was that touch with diffuse light perception, which excludes spatial cues, did not differ from touch without vision in performance accuracy, nor in location error pattern. The contrast between spatially relevant versus spatially irrelevant vision provides new, rather decisive, evidence against the hypothesis that vision affects haptic processing even if it does not add task-relevant information. The results support optimal integration theories, and suggest that spatial and non-spatial aspects of vision need explicit distinction in bimodal studies and theories of spatial integration.     

Perception of illumination direction in images of 3-D convex objects: influence of surface materials and light fields

We investigated the perception of illumination direction in images of 3-D convex objects under variations of light field and surface material properties. In a first experiment, we used an illumination-matching procedure in order to measure observers' ability to estimate the direction of illumination in images of 3-D polyhedra rendered under different light fields and illumination directions. Match deviations were larger in frontal direction than in rear directions, mainly counterclockwise in azimuth component, and diverged, in elevation component, from the image plane. In a second experiment, we examined whether the direction estimate was affected by the surface material type (BRDF), the light field, and the illumination direction. Angular deviations varied with material surface type and were largest in the test elevation direction 0 degrees. Elevation component deviations also differed with surface type and were larger in hemispherical diffuse lighting than in collimated lighting. These results suggest that the direction estimation is better with images of evenly distributed intensity gradients than with those of drastically varying gradients, and that the visual system may not take intensity variations due to the surface material or the light field into account in estimating the direction of illumination.     

A prior for global convexity in local shape-from-shading

To solve the ill-posed problem of shape-from-shading, the visual system often relies on prior assumptions such as illumination from above or viewpoint from above. Here we demonstrate that a third prior assumption is used--namely that the surface is globally convex. We use complex surface shapes that are realistically rendered with computer graphics, and we find that performance in a local-shape-discrimination task is significantly higher when the shapes are globally convex than when they are globally concave. The results are surprising because the qualitative global shapes of the surfaces are perceptually unambiguous. The results generalise findings such as the hollow-potato illusion (Hill and Bruce 1994 Perception 23 1335-1337) which consider global shape perception only.     

Perception of surface reflectance of 3-D geometrical shapes: influence of the lighting mode

We examined in three experiments whether the perception of surface reflectance in 3-D geometrical shapes is influenced by the mode of lighting, the level of surface reflectance, the number of polyhedral faces, and the regularity of polyhedral shape. As stimuli, we used simulations of regular polyhedra in a 2AFC constant-stimuli procedure to measure how large variations in the reflectance needed to be for observers to be able to tell whether the whole surfaces were uniform or non-uniform. In almost all the cases observers were more successful in discriminating non-uniform polyhedra in the hemispherical diffuse lighting conditions than in the collimated lighting conditions. The different levels of reflectance had no effect on the discrimination of non-uniformity. Second, as the number of faces of the shape increased, discrimination thresholds became lower, indicating that the interpretation of reflectance variations was better when a shape had many faces. Finally, the regularity of the shape, such as the central symmetry, was not an important factor. These results suggest that the interpretation of surface reflectance is more precise when surfaces have less variance in relative strengths between the face luminance values; these surfaces were the ones obtained under hemispherical diffuse lighting.     

环境光照的认知功效及其调节因素与作用机理

自人类视网膜上发现存在新型的内在光敏感神经节细胞以来, 环境光照对个体生理心理功能的非视觉作用备受研究者青睐, 其中环境光照对认知功能的非视觉作用结果并不十分一致且内在机理尚不明确。环境光照的认知功效会受到光学参数、光照模式、时间因素、个体差异以及任务特征等的共同调节。未来的研究需要从环境光对心理认知功能的作用模式, 动态办公照明系统的开发, 面向特殊群体的个性化照明以及光照非视觉作用产生的分子生物学机制等视角进行扩展和深化。     

Does face recognition rely on encoding of 3-D surface? Examining the role of shape-from-shading and shape-from-stereo

It is now well known that processing of shading information in face recognition is susceptible to bottom lighting and contrast reversal, an effect that may be due to a disruption of 3-D shape processing. The question then is whether the disruption can be rectified by other sources of 3-D information, such as shape-from-stereo. We examined this issue by comparing identification performance either with or without stereo information using top-lit and bottom-lit face stimuli in both photographic positive and negative conditions. The results show that none of the shading effects was reduced by the presence of stereo information. This finding supports the notion that shape-from-shading overrides shape-from-stereo in face perception. Although shape-from-stereo did produce some signs of facilitation for face identification, this effect was negligible. Together, our results support the view that 3-D shape processing plays only a minor role in face recognition. Our data are best accounted for by a weighted function of 2-D processing of shading pattern and 3-D processing of shapes, with a much greater weight assigned to 2-D pattern processing.     

Shape from shading from images rendered with various surface types and light fields

Shape constancy is referred to as the tendency for the perceived shape of an object to remain unchanged even under changed viewing and illumination conditions. We investigated, in two experiments, whether shape constancy would hold for images of 3-D solid objects defined by shading only, whose renderings differed in terms of surface material type (bi-directional reflectance distribution functions), light field, light direction, shape, and specularity. Observers were presented with the image of a sphere or an ellipsoid and required to set perceived orientation and cross-section profile on designated points of the image. Results showed that shape judgments varied with all the aforementioned variables except specularity. Shape estimates were more precise with specular than asperity scattering surfaces, collimated than hemispherical diffuse lighting conditions, lower than higher elevations, spherical than ellipsoidal shapes, but not different between surfaces having differing specularity. These results suggest that shape judgments are made largely on the basis of the overall intensity distribution of shading, and that the portions of intensity distribution that are due to nonstructural variables such as surface material type or light field are not excluded in the process of shape estimation, as if being due to structural components. It is concluded that little constancy is expected in the perception of shape from shading.     

Perceiving parts and shapes from concave surfaces

“A hole is nothing at all, but it can break your neck.” In a similar fashion to the danger illustrated by this folk paradox, concave regions pose difficulties to theories of visual shape perception. We can readily identify their shapes, but according to principles of how observers determine part boundaries, concavities in a planar surface should have very different figural shapes from the ones that we perceive. In three experiments, we tested the hypothesis that observers perceive local image features differently in simulated 3-D concave and convex regions but use them to arrive at similar shape percepts. Stimuli were shape-from-shading images containing regions that appeared either concave or convex in depth, depending on their orientation in the picture plane. The results show that concavities did not benefit from the same global object-based attention or holistic shape encoding as convexities and that the participants relied on separable spatial dimensions to judge figural shape in concavities. Concavities may exploit a secondary process for shape perception that allows regions composed of perceptually independent features to ultimately be perceived as gestalts.     

The role of binocular information in ball catching

The role of binocular vision in a ball-catching task involving spatial uncertainty was examined in three experiments. In all three experiments, subjects' catching performance was evaluated during monocular and binocular viewing, in normal room lighting and in complete darkness with a luminescent ball. Subjects' performance was found to be significantly better with binocular than with monocular vision, especially under normal lighting conditions. In the second and third experiments, catching performance was evaluated in the presence of minimal visual frames, consisting of a series of light-emitting diodes (LEDs). In Experiment 2, the visual frame consisted of a single plane of LEDs, whereas in Experiment 3, the visual frame consisted of two planes of LEDs. Catching performance was found to be significantly better with the visual frame than in complete darkness, but this was true only for binocular viewing. This result supports the hypothesis that binocular convergence is used to scale perceived space and that this information enables subjects to contact the ball successfully. It was further found that postural sway varied between lighting conditions and that less sway was accompanied by higher performance. There was no effect of binocular viewing in this respect. In general, the results suggest two additive effects of viewing conditions: a direct effect of binocular vision on ball catching and an indirect effect of lighting on postural stability, which, in turn, affects catching performance.     

The proximity structure of achromatic surface colors and the impossibility of asymmetric lightness matching

In asymmetric lightness matching tasks, observers sometimes report that they cannot achieve satisfactory matches between achromatic surfaces under different neutral illuminants. The surfaces appear different, yet no further adjustment of either surface improves the match. There are evident difficulties in interpreting data from a task that the observer cannot always do, and these difficulties likely affect the interpretation of a large number of previous studies. We investigated, as an alternative to asymmetric matching, the direct use of proximity judgments in the study of surface lightness perception. We asked observers to rate the perceived dissimilarity of pairs of achromatic surfaces that were placed in identical scenes and viewed under different neutral illuminants. We develop a parametric model that accurately predicts perceived dissimilarity in terms of physical light intensities and surface albedos. The parameters of this model are readily interpretable. In particular, the ratio of the influence of changes in illuminant intensity and changes in surface albedo is a measure of the extent to which the observer discounts the illuminant. Asymmetric lightness matching can be interpreted as an unachievable limiting case of proximity judgment.     

环境亮度对食品消费决策的影响：食品安全感知的中介作用

本研究考察了环境亮度对食品消费决策的影响,揭示了其发生的心理机制及边界。实验1和实验2发现环境亮度正向影响消费者支付意愿。这一效应的内在机制是因为明亮环境使消费者产生更高的食品安全感知,进而增加其对食品的支付意愿。对产品认证标签的检验进一步验证了安全感知的中介作用 (实验2)。结果表明,当食品具有认证标签时,食品安全感知无法中介环境亮度对消费者支付意愿的影响。     

The role of attention in children's time perception.

This study tested the role of attention in 7- to 9-year-old children's time estimation. Based on an attentional model of time estimation, it was hypothesized that prospective estimates of short intervals are a function of the degree to which a child is occupied with the passage of time and is focusing his or her attention on estimating the exposure time of a stimulus. Two experiments with two different manipulations on attentional focus were conducted. Eighty children were exposed to two types of light bulbs, one a big bulb kindled with high intensity and the other a small one kindled with low intensity. The light bulbs were kindled for different intervals ranging from 3 to 10 s. In both experiments children estimated the lighting time of the bulbs in each condition by a reproduction method. In the first experiment prospective time estimates were found to be significantly longer than retrospective ones. In the second experiment children gave shorter time estimates when their attention was attracted away from the time estimation task than when it was not. In both experiments the attentional hypothesis was supported. In addition, support for the "more is more" hypothesis was obtained. Implications for understanding children's time perception processes are discussed.     

Recognizing faces defined by texture gradients

Texture gradients can reveal surface orientation in a manner similar to shape from shading, and therefore provide an important cue for object recognition. In this study, we tested whether a complex 3-D object, such as a face, can be identified from texture gradients alone. The stimuli were laser-scanned faces for which the texture element was a fractal-noise pattern mapped onto the 3-D surface. An eight-alternative forced choice task was used in which participants matched a face defined by texture gradients to one of eight faces defined by shape from shading (Experiment 1) or by texture gradients (Experiment 2). On average, participants scored 24% and 18%, respectively, above chance in these experiments. Although this performance was much poorer than the performance based entirely on shape-from-shading stimuli (Experiment 3), the results suggest that texture gradient information may be used to recover surface geometry of complex objects.     

Simulating the role of visual selective attention during the development of perceptual completion

We recently proposed a multi‐channel, image‐filtering model for simulating the development of visual selective attention in young infants (Schlesinger, Amso & Johnson, 2007). The model not only captures the performance of 3‐month‐olds on a visual search task, but also implicates two cortical regions that may play a role in the development of visual selective attention. In the current simulation study, we used the same model to simulate 3‐month‐olds’ performance on a second measure, the perceptual unity task. Two parameters in the model – corresponding to areas in the occipital and parietal cortices – were systematically varied while the gaze patterns produced by the model were recorded and subsequently analyzed. Three key findings emerged from the simulation study. First, the model successfully replicated the performance of 3‐month‐olds on the unity perception task. Second, the model also helps to explain the improved performance of 2‐month‐olds when the size of the occluder in the unity perception task is reduced. Third, in contrast to our previous simulation results, variation in only one of the two cortical regions simulated (i.e. recurrent activity in posterior parietal cortex) resulted in a performance pattern that matched 3‐month‐olds. These findings provide additional support for our hypothesis that the development of perceptual completion in early infancy is promoted by progressive improvements in visual selective attention and oculomotor skill.     

Effects of indoor lighting (illuminance and spectral distribution) on the performance of cognitive tasks and interpersonal behaviors: The potential mediating role of positive affect

Three studies examined the effects of key aspects of indoor lighting (illuminance, spectral distribution) on the performance of tasks that did not primarily involve visual processing. It was hypothesized that lighting conditions which generated positive affect among subjects would influence behavior and cognition in ways consistent with the findings of previous research on the influence of such affect. Results of all three studies offered partial support for this hypothesis. In Study 1, male and female subjects exposed to relatively low levels of illuminance (150 lux) assigned higher performance appraisals to a fictitious employee and included a broader range of words in specific word categories than subjects exposed to relatively high levels of illuminance (1500 lux). In Study 2, subjects exposed to warm white light reported stronger preferences for resolving interpersonal conflicts through collaboration and weaker preferences for resolving conflicts through avoidance than subjects exposed to cool-white light. Additionally, illuminance and spectral distribution (color) interacted to influence subjects' self-set goals on a clerical coding task. In Study 3, receipt of a small, unexpected gift and exposure to warm-white light both increased the amount of time subjects were willing to donate as unpaid volunteers. In addition, in the absence of a gift, subjects volunteered more time under low than under high illuminance.This research was supported by funds from the Niagaru Mohawk Energy-Efficient Seed Research program and from the New York State Energy Research and Development Authority. Study 1 was conducted by Susan G. Daniels in partial fulfillment of requirements for the Master of Science degree. The authors wish to express their sincere appreciation to Marna Bronfen and Jill Thomley for their aid in collection of the data for Studies 2 and 3 and in statistical analyses. Thanks are also due to Sylvania, Inc., for supplying lamps, and to Bob Davis and Peter Boyce for their invaluable assistance in several respects.     

The effect of pre-cueing on spatial attention across perception and action

It is well established that processes of perception and action interact. A key question concerns the role of attention in the interaction between perception-action processes. We tested the hypothesis that spatial attention is shared by perception and action. We created a dual-task paradigm: In one task, spatial information is relevant for perception (spatial-input task) but not for action, and in a second task, spatial information is relevant for action (spatial-output task) but not for perception. We used endogenous pre-cueing, with two between-subjects conditions: In one condition the cue was predictive only for the target location in the spatial-input task; in a second condition the cue was predictive only for the location of the response in the spatial-output task. In both conditions, the cueing equally affected both tasks, regardless of the information conveyed by the cue. This finding directly supports the shared input-output attention hypothesis.     

On the motivational effects of positive verbal reinforcement on performance: Toward an inverted-U relationship

The purpose of this study was to ascertain the motivational effects of positive verbal reinforcement on the performance of a qualitative task. Male subjects performed on a task consisting of 24 slides that allowed them to test their decision-making abilities in simulated situations. Subjects performed under one of five noncontingent verbal reinforcement ratios (.00, .25, .50, .75, or 1.00). Subjects' accuracy and reaction times to each of the 24 slide stimuli were recorded and transformed into a total performance index. In line with an inverted-U hypothesis, it was hypothesized that if motivational effects of positive verbal reinforcement exist, they should induce a curvilinear relationship between reinforcement ratio and performance. This hypothesis was supported by the results of a trend analysis that showed that only the quadratic curvilinear term was significant. Inspection of means revealed the presence of an inverted-U curve such that performance gradually increased from ratio 0 and reached a maximum at ratio .50, following which a decrease in performance was obtained for ratios .75 and 1.00. Results support a motivational interpretation of the effects of positive verbal reinforcement on performance. Findings are discussed in light of the interaction between motivational and attentional processes.     

Neural coding partially accounts for the relationship between children’s number-line estimation and number comparison performance

Numerical comparison is a primary measure of the acuity of children’s approximate number system. Approximate number system acuity is associated with key developmental outcomes such as symbolic number skill, standardized test scores, and even employment outcomes (Halberda, Mazzocco, & Feigenson, 2008; Parsons & Bynner, 1997). We examined the relation between children’s performance on the numerical comparison task and the number-line estimation task. It is important to characterize the relation between tasks to develop mathematics interventions that lead to transfer across tasks. We found that number-line performance was significantly predicted by nonsymbolic comparison performance for participants ranging in age from 5 to 8 years. We also evaluated, using a computational model, whether the relation between the 2 tasks could be adequately explained based on known neural correlates of number perception. Data from humans and nonhuman primates characterized neural activity corresponding to the perception of numerosities. Results of behavioral experimentation and computational modeling suggested that though neural coding of numbers predicted a correlation in participants’ performance on the 2 tasks, it could not account for all the variability in the human data. This finding was interpreted as being consistent with accounts of number-line estimation in which number-line estimation does not rely solely on participants’ numerical perception.