Perceived angle of oscillatory motion

The general background of these experiments was the fact, known from e.g. trapezoidal window experiments, that rotary motion under certain conditions is perceived as oscillation. The aim was to identify the variables that determine the perceived angle of this oscillatory motion. Different shapes and different methods of generating the stimulation were used. No effect was obtained when varying the degree of trapezoidality of trapezoids, the location of the axis of rotation, the size of the stimulus pattern and the speed of the change. Both the occurrence and the perceived angle of oscillation was effected, however, by the width-height ratio of the stimulation, a decreasing ratio giving increasing occurrence of oscillation and decreasing perceived angle.     

Peripheral and foveal segmentation of angle textures

Studies of the effects of retinal eccentricity on the visual segmentation of textures are presented. The textures used in these studies were composed of angle elements. These were presented tachistoscopically to college students in three different experiments. Results showed that there were different relationships between segmentation performance and eccentricity, depending on the width of the angles used in the background and target texture. One major difference was that peak performance was found in the fovea in some conditions, and in peripheral areas in other conditions. Performance in the fovea and the periphery seemed to be determined by qualitatively different features. It was assumed that an appropriate explanation is that the system-internal representation of a specific stimulus within the early visual system differs as a function of the retinal location at which it is projected. Thus, the critical features discriminating between target and background texture have to be sought in the system-internal representation of the stimulus instead of in the stimulus itself. The data show that a relatively exact system-internal representation of the stimulus is present in the fovea, where performance is determined by angle width. In the periphery, in contrast, angles seem to be represented as “blobs,” and performance is determined by the orientation of the blobs’ main axes.     

The vascular cerebellopontile angle syndrome]

A cerebellopontine angle tumor cannot be reliably diagnosed from a classical clinicotopographic cerebellopontine angle syndrome. There is also a vascular cerebellopontine angle syndrome which is not too rare an occurrence. In some cases of tumorigenesis, where there is no papilledema and no characteristic increase in total liqour protein, it is not possible to make a clear decision between tumorous growth and vascular syndrome. The extension of the internal auditory meatus cannot be considered to be a symptom clearly indicating the presence of a tumor.     

Phlegmatic temperament from the psychiatric angle

Unlike the other five deadly sins of the Church, sloth is not attributed to an instinct or an impulse but to an anancastic form of reaction. A phlegmatic person is characterised by a lack of egoistic or altruistic instincts while feelings of nausea or fear are increased. Among phlegmatic persons those of clinical importance are epileptoid psychopaths, oblomovists and those exhibiting (forms of) phlegmatic temperament combined with obsessional or hysterical neurosis.     

The relationship between external thoracopelvic angle and lumbar segmental axial twist angle using an ultrasound imaging technique

The relationship between externally measured and internal spine axial twist motion (rotation about a vertical axis) is not well understood. Ultrasound is a validated technique for measurement of vertebral axial twist motion and has the potential for measuring segmental vertebral axial twist in vivo. The objective of this study was to evaluate lumbar segmental axial twist in relation to external thoracopelvic twist from optical motion capture using an ultrasound imaging technique. Sixteen participants were tested in a custom-built axial twist jig, which isolated motion to the lumbar spine. Participants were moved from neutral to 75% of maximum axial twist range of motion in an upright kneeling posture. Thoracopelvic motion was recorded with a motion capture system and L1 to S1 vertebral axial twist was recorded using ultrasound. From motion capture, maximum thoracopelvic axial twist motion was 41.1 degrees. From ultrasound, the majority of axial twist motion occurred at the L2-L3 (46.8% of lumbar axial twist motion) and L5-S1 (33.5%) intervertebral joints. Linear regression linking axial twist at each vertebral level to thoracopelvic axial twist ranged from 0.43 to 0.79. These findings demonstrate a mathematical relationship between internal and external axial twist motion and the distribution of motion across the lumbar spine suggests that classic use of L4-L5 to represent lumbar spine motion may not be appropriate for axial twist modelling approaches.     

Judgment of angle size: An experimental appraisal

Previous work on the estimation of angle size suggested that three factors play a significant part in the forming of an accurate estimation: the size of the angle, its orientation, and the mode in which the response is made. An examination of the judgment by 60 Ss of 12 angles under varied conditions of orientation, response mode, and cue was carried out with the result that the importance of size and orientation was confirmed. Despite an overall significant difference in estimation between response modes, there was no indication of a consistent effect across angles for the different modes. Predictions on the influence of orientation made by Fisher and Beery were tested, and while the former investigator was adequately supported, the latter was held to have reported results on a limited sample of angles which do not generalize to the wider range of angles used in the present study.     

Thatcher illusion: dependence on angle of rotation

The expression of a face with its eyes and mouth inverted changes from 'pleasant' to 'grotesque' as the stimulus is rotated from 180 degrees to 0 degree (Thatcher illusion). We determined the angular orientation at which this change occurred for three manipulated faces. Mean thresholds for eighteen observers were found to lie between 94 degrees and 100 degrees relative to the vertical with an average overlap of about 15 degrees between an observer's ascending and descending thresholds. The sudden nature and relatively narrow zone of the changeover suggest a neuronal step-tuning of hypothetical face cells in the human brain, underlying the holistic ('grotesque') versus componential ('pleasant') processing of upright versus upside-down faces. Findings are discussed within the framework of cognitive, neuroimaging, and single-cell studies.     

Perceived angle of incidence and achromatic surface color

Theory and evidence proposing illumination, and therefore necessarily angle of incidence of light, as a perceptual cue for lightness judgments are described. In two experiments, angle of incidence was varied by having 46 Ss view an upright trapezoid that monocularly appeared flat and binocularly, upright. In the first experiment, numbers of cues to the direction of a fixed source above the trapezoid were varied and combined. In a second experiment, the background for an illumination gradient was varied. Angle of incidence and cues to the location of the source did predict the trends in lightness judgments but not the magnitude of the effects. An alternative explanation to cue theory is proposed.     

Gaze angle explanations of the induced effect.

Mayhew and Longuet-Higgins formulated a computational explanation of the induced effect which successfully predicts the conditions under which the induced effect will occur. Underlying their theories are the assumptions that disparity information is separated into horizontal and vertical components and that the vertical disparities are used to calculate the gaze angles. An implementation of the fusional explanation introduced by Petrov makes similar predictions for the induced effect, but does not depend on these two assumptions.     

Visual angle and the word superiority effect

Two experiments are reported in which a word superiority effect is obtained under conditions where a fixed set of alternatives are employed with positional certainty as to the critical letter, trial type (word or nonword) is mixed, and the subject is told to fixate the position of the critical letter. A third experiment employed the same methodology except for the fact that the stimuli subtended a larger retinal angle. No word superiority effect was observed in the third experiment. It is suggested that the visual angle of the stimulus display is a crucial factor in experiments on the word superiority effect.     

Children's use of the bearing angle in interceptive actions

The authors investigated the effect of ball velocity and walking direction on children's adherence to the constant bearing angle (CBA) strategy. Children (N = 20) approached a moving ball to manually intercept it at a predefined target area. Results revealed that 10- to 12-year-olds adhered more than 5- to 7-year-olds to the CBA strategy. Younger children deviated more than older children from smaller angles of approach and lower ball velocities. The present findings suggest that younger children have difficulty adjusting to task requirements because they fail to couple walking velocity with ball velocity. The improvement seen with increasing age suggests that compliance with the CBA strategy may be attributed to older children's enhanced coincidence anticipation.     

从文化视角观照道教之特色

1、道教产生于中国 ,在历史上影响波及朝鲜半岛和日本 ① ,在近现代还传播到欧美等地。对道教在中国宗教史以及在中国传统文化中的定位 ,已有许多前辈学者从不同的角度加以阐扬。但从我们的教学实践和理论研究中感到 ,把道教作为一个特有的宗教文化现象加以研究 ,无论对于道教本身的认识 ,还是对于道教对中国文化的影响都是应该引起我们关注的一个视角。2、在许多人的印象中 ,道教与佛教、基督教、伊斯兰教比较起来 ,是个体系庞杂、支脉繁多的宗教 ,此种观点 ,可以元代学者马端临为代表 :“道家之术杂而多端 ,先儒之论备矣。盖清净一说也 ,…     

An unobtrusive measurement method of the horizontal gaze angle

A horizontal gaze angle measurement device is introduced. By combining a photoelectric viewing device to measure the horizontal eye angle with a similar head angle measurement device, it is possible to measure the horizontal gaze angle without using a headrest. After discussion of circuit diagrams and measurement principles, it is shown that the measurements made with the device yield a reasonable precision. The mean absolute measurement error is below 1°. This inexpensive and unobtrusive device covers a visual field of about 20° and can be used in parallel with many tasks. Further, data on the successful application of the device in a driving simulation setting are discussed.     

Visual angle as a determinant of perceived interobject distance

Two new experiments and a reanalysis of Toye’s (1986)data are used to examine the relationship between true distance and perceived distance in natural scenes. In the first experiment, 8 subjects estimated 78 interobject distances, formed by all pairs of 13 objects, while viewing the objects from a fixed position. The results showed that estimated distance is a linear function of the visual angle between objects as well as of the true distance. This relationship results in distances perpendicular to the line of sight being overestimated in relation to true distances and to distances parallel to the line of sight. These findings were confirmed by reanalysis of a comparable data set from Toye. Since changes in the visual angle can come about through changes in alignment with the line of sight, viewing distance, or interobject distance, Experiment 2 was designed to determine whether the visual angle effect was due to one of these, or whether it was an independent effect. In Experiment 2, 8 subjects estimated six interobject distances from 12 viewing positions. The results showed that visual angle predicted estimated distance independently of how the change in visual angle came about, suggesting that the greater the visual angle between objects, the more their separation is overestimated.     

Stationary visual texture and the estimation of slant angle

Gibson (1950a) has suggested that a gradient of retinal stimulation from an irregularly textured surface is used in the estimation of slant. There are several measures that could form such a gradient. Eight pictures of slanting surfaces were constructed with the aid of a computer. These consisted only of texture elements: in this case, outline circles and ellipses. Subjects studied pairs of pictures and indicated which had the greater tilt. By varying separately the gradients of element size and element density, it was possible to show that only the former contributed appreciably to the impression of slant. Only some of the measures considered are consistent with this result.