Distance estimation in vista space

Although distance estimation has been extensively studied in the laboratory, our ability to judge large distances in the field is not well researched. We challenge the notion that large distances are uniformly underestimated. We presented different targets to observers at distances ranging from 25 to 500 m to obtain egocentric distance judgments in natural environments. Three experiments showed that observers tend to underestimate distances below 75 m in a large open field, whereas they overestimate farther distances. Both the eye height of the observer and the size of the target also influenced distance estimation. We conclude that the notion of a uniform vista space has to be reconceived.     

Distance perception within near visual space

We investigated the perception of distance of visual targets with constant size and luminance presented between 20 and 120 cm from subjects' eyes. When retinal disparity cues were present, the subjects could reproduce very accurately the distance of a seen reference in this area. When only extraretinal information was available, distance perception was still correct for distances of 40 cm or less. However, distances beyond 60 cm were underestimated. When forced to evaluate the distance between a reference and themselves, e.g. when evaluating the absolute distance or half the distance or twice the distance of a reference, subjects used an egocentric plane of reference located on average 10.4 cm in front of their eyes. Measurements of binocular eye movements indicated a clear relationship between vergence angle and target distance. The egocentric plane of reference at 10.4 cm also corresponds to the maximum achievable vergence. These results suggest that ocular convergence can be used as a reliable cue for distance within the arm's reaching space.     

Distance discrimination in a simulated space environment

The just noticeable difference (JND) for distance was investigated by a paired-comparisons method using successive comparisons. The research utilized an optically simulated large target located in a textureless environment at distances along the saggital plane out to 12, 800 ft. The value of ΔD/D varied from less than 3% at 200 ft to about 7% at 12, 800 ft. The results confirmed a power function relationship between distance threshold and observation distance.     

Distance estimates of children as a function of acquisition and response activities

Second and sixth graders (8 and 12 years of age, respectively) experienced a large-scale environment either actively or passively followed by a distance estimation task requiring either active or passive activity. Second graders were most accurate in those conditions where acquisition and response activities were congruent. These children significantly overestimated distances in the passive acquisition-active response condition. Sixth graders were equally accurate across all four experimental conditions. Results are discussed in terms of the complex interaction between acquisition factors and task demands which influence interpretations about spatial representations.     

Depth interval estimates from motion parallax and binocular disparity beyond interaction space

Static and dynamic observers provided binocular and monocular estimates of the depths between real objects lying well beyond interaction space. On each trial, pairs of LEDs were presented inside a dark railway tunnel. The nearest LED was always 40 m from the observer, with the depth separation between LED pairs ranging from 0 up to 248 m. Dynamic binocular viewing was found to produce the greatest (ie most veridical) estimates of depth magnitude, followed next by static binocular viewing, and then by dynamic monocular viewing. (No significant depth was seen with static monocular viewing.) We found evidence that both binocular and monocular dynamic estimates of depth were scaled for the observation distance when the ground plane and walls of the tunnel were visible up to the nearest LED. We conclude that both motion parallax and stereopsis provide useful long-distance depth information and that motion-parallax information can enhance the degree of stereoscopic depth seen.     

Simulation analyses of space use: Home range estimates,variability, and sample size

Simulations of space use by animals were run to determine the relationship among home range area estimates, variability, and sample size (number of locations). As sample size increased, home range size increased asymptotically, whereas variability decreased among mean home range area estimates generated by multiple simulations for the same sample size. Our results suggest that field workers should ascertain between 100 and 200 locations in order to estimate reliably home range area. In some cases, this suggested guideline is higher than values found in the few published studies in which the relationship between home range area and number of locations is addressed. Sampling differences for small species occupying relatively small home ranges indicate that fewer locations may be sufficient to allow for a reliable estimate of home range. Intraspecific variability in social status (group member, loner, resident, transient), age, sex, reproductive condition, and food resources also have to be considered, as do season, habitat, and differences in sampling and analytical methods. Comparative data still are needed.     

Small and unfilled psychotherapy groups: Understanding and using them effectively

Many open-ended psychotherapy groups have fewer than five members, and fewer than the number the therapist considers necessary for the group to be filled. This paper discusses the rationale for starting such groups and the special dynamics of running them. It then suggests strategies for the therapist to use in maximizing their therapeutic effectiveness. Suggestions are made for further research into the demographic and dynamic aspects of such groups.     

美学"心理距离说"的哲学认识论联想

本文从审美与认识的异中求同,提出了认识过程中“距离”的存在可以缩小认识成果与真理之间距离的基本观点,多角度地分析了时空距离和心理距离在认识过程中的作用,论述了研究认识过程中距离效应的重要价值。     

Time judgments of musical endings: effects of expectancies on the "filled interval effect"

In two experiments, the influence of musical endings on duration judgments was examined. In Experiment 1, subjects were asked to compare the duration of paired folk tunes that could vary in their degree of resolution. Results showed that melodies ending on the leading tone interval were underestimated relative to songs ending on the conventional tonic. Experiment 2 further revealed that time estimates were influenced by a melody's preceding temporal accent structure. Melodies ending earlier than expected were judged significantly shorter, particularly when the tune ended on the leading-tone interval. Conversely, tonic endings were judged substantially longer when they appeared to occur "too late" in time. Results are discussed in terms of a contrast model which emphasizes the role of expectancies on duration judgments.     

Distance cognition in virtual environmental space: Further investigations to clarify the route-angularity effect

Two experiments with 72 participants in total investigated the route-angularity effect. This effect is shown when a greater number of turns along a route increase the estimated length of this route. In this study it was shown that the route-angularity effect is likely to be a memory-based effect depending on task difficulty. The important factor seems to be how heavily memory is loaded during learning. The route-angularity effect even appears in intentional learning, when memory is loaded heavily. Under this learning condition participants know beforehand that they have to estimate distances. All experiments were conducted in a controlled virtual environment, which allows a reliable investigation of distance estimations in environmental space.     

Body-image, personal space and self-esteem: preliminary evidence for "focusing" effects

A repeated-measures design was used to investigate the effects of a self-esteem manipulation on measures of body-image and personal space. Significant interaction effects were obtained for penetration, body-cathexis, and simulated interaction distance, and the results confirmed the prediction that subjects whose self-esteem had been enhanced would obtain significantly higher body-cathexis, and significantly lower penetration and interaction distance scores than those whose self-esteem had been reduced. Although the interaction effect was nonsignificant, similar trends were observed for barrier. Figure drawing and spatial orientation appeared to be unrelated to self-perception. Factor analysis showed that the tests were unrelated, but the self-esteem manipulation had a "focusing" effect on boundary and interaction distance. Overall, the results provide experimental support for the defensive distancing hypothesis.     

Size estimates of action-relevant space remain invariant in the face of systematic changes to postural stability and arousal

Perceptual estimates of action-relevant space have been reported to vary dependent on postural stability and concomitant changes in arousal. These findings contribute to current theories proposing that perception may be embodied. However, systematic manipulations to postural stability have not been tested, and a causal relationship between postural stability and perceptual estimates remains to be proven. We manipulated postural stability by asking participants to stand in three differently stable postures on a force plate measuring postural sway. Participants looked at and imagined traversing wooden beams of different widths and then provided perceptual estimates of the beams’ widths. They also rated their level of arousal. Manipulation checks revealed that the different postures resulted in systematic differences in body sway. This systematic variation in postural stability was accompanied by significant differences in self-reported arousal. Yet, despite systematic differences in postural stability and levels of arousal perceptual estimates of the beams’ widths remained invariant.     

One-dimensional and multi-dimensional studies of the exocentric distance estimates in frontoparallel plane, virtual space, and outdoor open field

The aim of this study is twofold: on the one hand, to determine how visual space, as assessed by exocentric distance estimates, is related to physical space. On the other hand, to determine the structure of visual space as assessed by exocentric distance estimates. Visual space was measured in three environments: (a) points located in a 2-D frontoparallel plane, covering a range of distances of 20 cm; (b) stakes placed in a 3-D virtual space (range = 330 mm); and (c) stakes in a 3-D outdoors open field (range = 45 m). Observers made matching judgments of distances between all possible pairs of stimuli, obtained from 16 stimuli (in a regular squared 4 x 4 matrix). Two parameters from Stevens' power law informed us about the distortion of visual space: its exponent and its coefficient of determination (R2). The results showed a ranking of the magnitude of the distortions found in each experimental environment, and also provided information about the efficacy of available visual cues of spatial layout. Furthermore, our data are in agreement with previous findings showing systematic perceptual errors, such as the further the stimuli, the larger the distortion of the area subtended by perceived distances between stimuli. Additionally, we measured the magnitude of distortion of visual space relative to physical space by a parameter of multidimensional scaling analyses, the RMSE. From these results, the magnitude of such distortions can be ranked, and the utility or efficacy of the available visual cues informing about the space layout can also be inferred.     

Distance and Dissimilarity

Abstract

This paper considers whether an analogy between distance and dissimilarity supports the thesis that degree of dissimilarity is distance in a metric space. A traditional way to justify the thesis would be to prove representation and uniqueness theorems, according to which if comparative dissimilarity meets certain qualitative conditions, then it is representable by distance in a metric space. But I will argue that those qualitative conditions which are strong enough to capture the analogy between distance and dissimilarity are not met by either actual or possible particulars.     

Distance underestimation in virtual space is sensitive to gender but not activity-passivity or mode of interaction.

Four groups of undergraduates (half of each gender) experienced a movement along a corridor containing three distinctive objects, in a virtual environment (VE) with wide-screen projection. One group simulated walking along the virtual corridor using a proprietary step-exercise device. A second group moved along the corridor in conventional flying mode, depressing a keyboard key to initiate continuous forward motion. Two further groups observed the walking and flying participants, by viewing their progress on the screen. Participants then had to walk along a real equivalent but empty corridor, and indicate the positions of the three objects. All groups underestimated distances in the real corridor, the greatest underestimates occurring for the middle distance object. Males' underestimations were significantly lower than females' at all distances. However, there was no difference between the active participants and passive observers, nor between walking and flying conditions.     

"I came so that they may have life": amative space and faith as vital concern

This article describes four attributes of faith as vital concern--relational spontaneity, responsiveness, receptiveness, and vulnerability--which are key ingredients to subjective and intersubjective experiences of being alive and real. The metaphor, amative space, refers to the processes and dynamics that make faith as vital concern a viable possibility between and among people. The author depicts these processes as four, interrelated dialectical pairs--recognition-negation, surrender-generation, trust-distrust, and disruption-repair. The four attributes of faith as vital concern combined with the processes and dynamics of amative space can be used as a relational model to understand faith experience and interactions of individuals and groups.