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At least 1,117 records · Page 62Linked to original sources
PubMed1988

Shape similarity and distance disparity as apparent motion correspondence cues.

Apparent motion is perceived when two spots of light are presented successively in different locations. When more than one element is present in each frame, there is a correspondence problem in matching the elements in one frame with those in the other. We report the effects of shape similarity and distance disparity on the correspondence process. Twenty subjects were tested using a 2-AFC design. We found that both shape and distance cues are used by the correspondence process: when distance is the only cue the motion which is usually perceived is that involving the shorter distance; when shape is the only cue the motion involving two elements of the same shape is preferred. We also studied the interaction between the two cues when both were present. Quantitative measures of the relative strengths of these effects and of their interaction are reported. A Signal Detection Theory model is used to analyze these apparent motion correspondence effects.

Cues↗
PubMed1985

The effects of distance between interactants and subject anxiety on conjugate lateral eye movements.

Ehrlichman and Weinberger (1978, Psychological Bulletin 85, 1080-1101) have suggested that the distance between participants during face-to-face interviewing may be a significant determinant of directional patterns of conjugate lateral eye movements (CLEMS). As predicted, at the longer, social distance CLEMS were dependent on the verbal or spatial nature of questions; when interactants were at a closer, personal distance CLEMS became more consistent in direction, regardless of problem type. Distance manipulation also differentially altered CLEM patterns for the two sexes.

Adult↗
PubMed2004

Project based experiential distance education: an oxymoron?

In the context of a program in Health Information Science at the University of Victoria in Victoria, BC, Canada, we have over the past 20 years made progress and gained experience in delivering a number of courses in a project-based experiential learning mode which links professionals and students in real world projects. As we are moving towards distance education, we are facing the challenge of translating these achievements into distance mode. The paper reviews the principles which make project-based educational mode involving collaboration with professionals desirable. We then review the experience with two specific courses, in which local students work with distant and local representatives of health institutions, respectively, on projects defined in the professional environment. This experience showed that the approach is of mutual interest and benefit to both the students and the professionals involved, but that a long lead time, and considerable detail in the preparation are required to lead such endeavors to success. We then discuss three alternatives to translating the principles of these approaches into distance mode. Among the alternatives, conducting a local project, closely affiliated with the teaching institution, or relying on a mock project which is based on recorded examples from previous projects, seem to be the most promising options. The alternative of having every student pursuing a different project, which may be local for the student but distant for the educational institution, is less attractive if faculty are expected to assume responsibility for successful project completion. It may, however, be the preferred solution if students are health professionals residing at distant health care institutions. All three alternatives have drawbacks that may limit the feasibility of project-based experiential learning in distance mode.

British Columbia↗
PubMedDate not supplied

Evaluation strategies for midwifery education linked to digital media and distance delivery technology.

The goal of the teaching and learning process for health professionals is the acquisition of a fundamental core of knowledge, the demonstration of critical thinking ability, and the demonstration of competency in the performance of clinical skills. Teaching and learning in distance education programs require that the administration, teachers, and students be creative in developing evaluation strategies that can be adapted to the challenges of the cyberspace on-line educational environment. Evaluation standards for distance education programs recently have been delineated by federal agencies, private organizations, and academic accreditation associations. These standards are linked to principles of sound education practice that promote program quality, high levels of student-faculty interaction, and support effective teaching and learning in the distance education context. A growing body of evidence supports the conclusion that technology-enhanced teaching is equivalent in effectiveness compared with traditional methods when student-learning outcomes are the focus of measurement. An allied body of literature offers model approaches that can be useful to educators who must also conduct the evaluation of clinical skills, provide feedback, and promote socialization to the nurse-midwifery/midwifery role for students being educated in whole or in part through instruction delivered at a distance.

Benchmarking↗
PubMed2004

Effects of distance learning on clinical management of LUTS in primary care: a randomised trial.

AIM: To determine the effect of a distance learning programme on general practice management of men with lower urinary tract symptoms (LUTS). METHODS: A cluster randomised controlled trial was performed. General practitioners (GPs) were randomised to a distance learning programme accompanied with educational materials or to a control group only receiving mailed clinical guidelines on LUTS. Clinical management was considered as outcome. RESULTS: Sixty-three GPs registered care management of 187 patients older than 50 years attending the practice because of LUTS. The intervention group showed a lower referral rate to a urologist (OR: 0.08 (95% CI: 0.02-0.40)), but no effect on PSA testing or prescription of medication. PSA testing tended to be requested more frequently by intervention group GPs. Secondary analysis showed patients in the intervention group received more educational materials (OR: 75.6 (95% CI: 13.60-419.90)). CONCLUSIONS: The educational programme had impact on clinical management without changing PSA testing. Distance learning is an promising method for continuing education. PRACTICE IMPLICATIONS: Activating distance learning packages are a potentially effective method for improving professional performance. Emotional matters as PSA testing probably need a more complex approach.

Adult↗
PubMed2005

Prolongation of latency of horizontal saccades in elderly is distance and task specific.

The present study examined horizontal saccades in healthy subjects: 9 adults (20-32 years) and 10 aged subjects (63-83 years), under gap (fixation target extinguishes prior to target onset) and overlap (fixation stays on after target onset). The gap paradigm is known to promote fast initiation of saccades while the overlap paradigm promotes voluntary saccades with longer latency. In real life we perform saccades at various distances. In this study each paradigm was run at three viewing distances-20, 40 and 150 cm, corresponding to a convergence angle of 17.1 degrees, 8.6 degrees and 2.3 degrees, respectively. Eye movements were recorded with the Chronos video eye tracker or with the photoelectric IRIS. The main findings are: (i) increase in latency of saccades with age, with distance and with the overlap condition; (ii) evidence for interaction between these factors, indicating the following anomaly: in the gap condition and at near, aged subjects show short latencies similar to those of young adults; (iii) express type of latencies (between 80 and 120 ms) occur most frequently at near in the gap condition and at similar rates in young (25%) and aged subjects (20%). The specificity of close distance combined with the gap for triggering short latency saccades could be related to both attention and oculomotor fixation disengagement. The strength of coupling between fixation-eye movement control and visual attention control varies for different locations in space, and its decline with aging can be also different.

Adult↗
PubMed1998

Judging distance from ocular convergence.

Subjects misjudge distances considerably when forced to rely on extra-retinal information. Nevertheless, they can reproducibly set a target to the same distance as a reference, or to double or half that distance, even when they have to look back and forth between them because they are prevented from seeing one when looking at the other. Our explanation for this apparent discrepancy is that people have access to reasonably accurate extra-retinal information on changes in ocular convergence, but can only use this information to judge distances if they had reliable information about the orientation of the eyes before the convergence changed.

Convergence, Ocular↗
PubMed2004

Familiarity with mental illness and social distance from people with schizophrenia and major depression: testing a model using data from a representative population survey.

OBJECTIVES: The main purpose of this study is to examine whether the relationship between familiarity with mental illness and stigmatizing attitudes about mental illness, which had been observed in a previous study based on a sample of community college students (Psychiatr. Serv. 52 (2001) 953), can be replicated using data from a representative population survey. METHODS: In spring 2001, a representative survey was carried out in Germany (n=5025). A personal, fully structured interview was conducted which began with the presentation of a vignette depicting someone with either schizophrenia or major depression. Respondents were asked to respond to measures assessing familiarity, perception of dangerousness, fear, and social distance. Path analysis with manifest variable structural modeling techniques was applied to test the model used in the previous study. RESULTS: Despite differences in methods, most findings of the previous study were replicated. Respondents who were familiar with mental illness were less likely to believe that people with schizophrenia or major depression are dangerous. Weaker perceptions of dangerousness corresponded closely with less fear of such people, which in turn was associated with less social distance. The effect of familiarity was somewhat pervasive: respondents who reported to be familiar with mental illness expressed a less strong desire for social distance. There is also a relatively strong relationship between perceived dangerousness and social distance. CONCLUSIONS: Our findings fully support the notion that approaches to social change which increase the public's familiarity with mental illness will decrease stigma.

Adolescent↗
PubMed1988

Haptically perceiving the distances reachable with hand-held objects.

Nine experiments are reported on the ability of people to perceive the distances reachable with hand-held rods that they could wield by movements about the wrist but not see. An observed linear relation between perceived and actual reaching distances with the rods held at one end was found to be unaffected by the density of the rods, the direction relative to the body in which they were wielded, and the frequency at which they were wielded. Manipulating (a) the position of an attached weight on an otherwise uniformly dense rod and (b) where a rod was grasped revealed that perceived reaching distance was governed by the principal moment(s) of inertia (I) of the hand-rod system about the axis of rotation. This dependency on moment of inertia (I) was found to hold even when the reaching distance was limited to the length of rod extending beyond an intermediate grasp. An account is given of the haptic subsystem (hand-muscles-joints-nerves) as a smart perceptual instrument in the Runeson (1977) sense, characterizable by an operator equation in which one operator functionally diagonalizes the inertia and strain tensors. Attunement to the invariants of the inertia tensor over major physical transformations may be the defining property of the haptic subsystem. This property is discussed from the Gibsonian (ecological) perspectives of information as invariants over transformations and of intentions as extraordinary constraints on natural law.

Adult↗
PubMed1997

Visual perception of egocentric distance as assessed by triangulation.

Two triangulation methods for measuring perceived egocentric distance were examined. In the triangulation-by-pointing procedure, the observer views a target at some distance and, with eyes closed, attempts to point continuously at the target while traversing a path that passes by it. In the triangulation-by-walking procedure, the observer views a target and, with eyes closed, traverses a path that is oblique to the target; on command from the experimenter, the observer turns and walks toward the target. Two experiments using pointing and 3 using walking showed that perceived distance, averaged over observers, was accurate out to 15 m under full-cue conditions. For target distances between 15 and 25 m, the evidence indicates slight perceptual underestimation. Results also show that observers, on average, were accurate in imaginally updating the locations of previously viewed targets.

Adolescent↗
PubMed1980

Apparent distance of sounds recorded in echoic and anechoic chambers.

With miniature microphones inserted into the external ear canals of a model and the sound source 90 degrees to left of midline, low-pass, and broadband noise bursts were picked up and recorded on magnetic tape. The bursts were generated in two highly contrasting acoustic environments: an anechoic and an echoic chamber. The taped sounds were played back monaurally and binaurally via headphones to 16 listeners seated in an acoustically neutral setting. They were instructed to estimate the distance of the stimuli. Apparent distances of bursts recorded in the echoic or reverberant chamber far exceeded those recorded in the anechoic chamber. It mattered not whether the sounds were presented monaurally or binaurally. What did influence distance estimates dramatically was the frequency composition of the stimuli. Low-pass sounds recorded in either acoustic environment were consistently judged to be further removed than high-pass sounds recorded in the same setting. They were also more likely to appear from behind the listener. In our moment-to-moment transaction with the acoustic environment, distant sounds generally have less acoustic energy in the higher audio frequency. We suggest that this lifetime of auditory experience influenced our listeners' scale of relative distance.

Auditory Perception↗
PubMed1982

Application of geometric models to letter recognition: distance and density.

This article reviews studies in which a single letter is visually presented under adverse conditions and the subject's task is to identify the letter. The typical results for such studies are (a) certain pairs of letters are more often confused than other pairs of letters; (b) certain letters are more easily recognized than others; and (c) confusion errors for a letter pair are often asymmetric, the number of errors differing depending on which letter of the pair is presented as the stimulus. A geometric model incorporating the properties of distance and spatial density (after Krumhansl) is presented to account for these results. The present application of the distance-density model assumes that each letter is constructed in a typical 5 X 7 dot matrix. Each letter is represented in 35-dimensional space based on its constituent dots. A central idea behind the model, embodied in the property of spatial density, is that an explanation of typical results must take into account the relationship of the entire stimulus set to both the presented letter and the responded letter. Specifically, according to the model, (a) pairs of letters that are close in geometric space are more often confused than pairs of letters that are distant; (b) letters that are in less spatially dense regions are more easily recognized than letters that are in more spatially dense regions; and (c) asymmetric confusion errors result when one member of a letter pair is in a denser region than the other member of the letter pair. The distance-density model is applied to published and unpublished results of the authors as well as published results from two other laboratories. Alternative explanations of the three typical letter recognition results are also considered. The most successful alternative explanations are (a) confusions are an increasing function of the number of dots that two letters share; (b) letters constructed from fewer dots are easier to recognize; and (c) asymmetries arise when one member of a letter pair is more easily recognized, since that letter then has fewer confusion errors to give to the other letter of the pair. The model is discussed in terms of the distinction between template matching and feature analysis. An alternative classification of letter recognition models is proposed based on the global versus local qualities of features and the spatial information associated with each feature. The model is extended to explain reaction time study results. It is suggested that the distance-density model can be used to create optimal letter fonts by minimizing interletter confusions and maximizing letter recognizability.

Discrimination Learning↗
PubMed1987

Application of a cognitive-distance model to learning in a simulated travel task.

A cognitive-distance model for choice, obtained by specializing a general class of models for categorization, was tested in a situation simulating the task of controlling speed of a vehicle in tasks defined by different relations between speed and probability of delay. Subjects exhibited significant learning whenever delay schedules permitted greater-than-chance performance, but on the average they did not approach optimal performance in the sense of choosing speeds so as to maximize distance attained in allowed time. Evidence was obtained that subjects encoded information about probabilities of delay and distributions of distance attained at different speeds quite accurately in memory and that suboptimal performance was due primarily to imperfect discrimination among representations of choice alternatives on a cognitive scale of expected distance.

Adult↗
PubMed1987

Exploring environments by hand or foot: time-based heuristics for encoding distance in movement space.

In Experiment 1, blindfolded observers judged (a) the distance of pathways felt by hand and (b) the straight-line distance between pathway endpoints inferred from such exploration. In Experiment 2, blindfolded observers made corresponding estimates after traversing similar pathways on foot. Pathways were explored under three different speeds. Under both manipulatory and ambulatory exploration, there was substantial length distortion of inferred distance: The straight-line distance was increasingly overestimated with increases in the length of the explored pathway. With manipulatory exploration, slower movements increased length distortion, but duration effects proved secondary to effects of spatial extent. For ambulatory exploration, no duration effects were obtained. Observers used time-independent heuristics, that is, a footstep metric for estimating the pathway actually travelled and a spatial imaging strategy for estimating the inferred line between pathway endpoints. The studies establish length distortion as a general phenomenon in movement space and identify its major causes as spatial rather than temporal.

Adult↗
PubMed1998

Effects of hippocampal and parietal cortex lesions on memory for egocentric distance and spatial location information in rats.

To assess the working memory system for egocentric distance and place information, delayed matching-to-sample (DMTS) go/no-go tasks were run for each rat. To assess the reference memory system, and to serve as a control for nonmemory deficits, successive discrimination go/no-go tasks were then conducted using the same rats. Rats with hippocampal, but not parietal cortex, lesions were impaired relative to controls in the working memory (DMTS) task for both egocentric distance and place information, although the deficit observed in the working memory task for egocentric distance information by rats with hippocampal lesions was mild. Neither hippocampal nor parietal cortex lesioned rats were impaired relative to controls in the reference memory (successive discrimination) task for either cue. The hippocampus appears to be involved in working memory for egocentric distance and in spatial location information, whereas the parietal cortex is not.

Analysis of Variance↗
PubMed1995

Dominance fades with distance: an experiment on food competition in long-tailed macaques (Macaca fascicularis).

Dominant animals often can suppress the competitive behavior of subordinates by overt aggression or by their mere presence. This experiment on pairs of long-tailed macaque females explored whether this effect of dominant animals is influenced by interindividual distance. A dominant and a subordinate, but stronger, animal could compete for food by a tug-of-war on a bar. The animals were separated by 2 grids, spaced at either 30 or 100 cm. At 30 cm, 7 of 8 subordinate subjects either did not pull the bar or did not obtain a major share of the available food. In contrast, at 100 cm, all subordinate subjects obtained more food than the dominant. Thus, the dominant animals could suppress the competitive behavior of the subordinate only at the short interindividual distance, despite the fact that the dominant could not approach or attack even at the short distance and could be fully seen by the subordinate even at the large distance.

Animals↗
PubMed2001

Distance determined by the angular declination below the horizon.

A biological system is often more efficient when it takes advantage of the regularities in its environment. Like other terrestrial creatures, our spatial sense relies on the regularities associated with the ground surface. A simple, but important, ecological fact is that the field of view of the ground surface extends upwards from near (feet) to infinity (horizon). It forms the basis of a trigonometric relationship wherein the further an object on the ground is, the higher in the field of view it looks, with an object at infinity being seen at the horizon. Here, we provide support for the hypothesis that the visual system uses the angular declination below the horizon for distance judgement. Using a visually directed action task, we found that when the angular declination was increased by binocularly viewing through base-up prisms, the observer underestimated distance. After adapting to the same prisms, however, the observer overestimated distance on prism removal. Most significantly, we show that the distance overestimation as an after-effect of prism adaptation was due to a lowered perceived eye level, which reduced the object's angular declination below the horizon.

Accommodation, Ocular↗
PubMed1983

Magnitude estimation of oral cavity distances.

Adult subjects were asked to estimate relative distances between points marked on artificial palates fitted to their own palatal vaults. The artificial palates were less than 1 mm thick and extended posteriorly along the hard palate from the central incisors to approximately the second molars. Distances of 4, 8, 12, 16, and 20 mm were marked on four planes on the palates, one corresponding to the alveolar ridge, one anterior and two posterior to the ridge. The subjects felt raised points on the palates with their tongues and assigned number referenced to a standard distance on the alveolar plane. The eight adults performed the task very reliably, and the growth of scores corresponded closely to the increases in distance among the points judged. Accuracy did not vary with the particular plane, and performance was as accurate on the first trial as it was on the fifth. These subjects displayed very precise proprioceptive-kinesthetic knowledge of the oral cavity.

Adult↗