Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Distance Perception”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
PubMed1989

Simultaneous adaptation to size, distance, and curvature underwater.

Perceptual adaptation to underwater size, distance, and curvature distortion was measured for four different adaptation conditions. These conditions consisted of (a) playing Chinese checkers underwater, (b) swimming with eyes open underwater, (c) viewing a square underwater, and (d) an air control. Significant adaptation to underwater distortions was recorded in all except the air control condition. In the viewing square condition a positive correlation between size and distance adaptation was noted. It was suggested that adaptation to curvature may have mediated the positive correlation. Possible applications for the training of divers are discussed.

Adaptation, Ocular↗
PubMed1990

Visibility distance of highway signs among young, middle-aged, and older observers: icons are better than text.

The visibility distances for young, middle-aged, and elderly observers of text and icon versions of four different highway signs were compared under day and dusk lighting conditions. No age differences were observed. Icon signs, however, were visible at much greater distances than were text signs for all three age groups, a difference that was more pronounced under dusk conditions. There were no age differences in the comprehension of icon signs, but there was considerable variability from one icon sign to another in the degree to which they were comprehended. Acuity was found to be a better predictor of the visibility distance of text signs in both day and dusk conditions than it was of icon signs. To the degree that they are comprehended, icon signs appear to offer drivers of all ages almost twice as much time in which to respond to them.

Adult↗
PubMed1992

Apparent size and distance in an imaging display.

The size-distance invariance hypothesis suggests that the perceived size and the perceived distance of objects in a field viewed naturally are closely related. However, this relationship breaks down when scenes are viewed through high-power optical systems. When natural scenes are viewed through an imaging display of unity magnification, there is a reduction in their apparent size. This raises the question of whether the relationship breaks down when scenes are viewed through a low-power imaging display. A single-lens reflex camera was used as an imaging display that enabled subjects to vary the size of imaged real-world scenes. Judgments of size were found to vary with depth information in scenes and between monocular and binocular viewing, consistent with a previous finding, but judgments of distance did not vary significantly across either of these conditions. The results suggest that judgments of size and judgments of distance with imaging displays are not influenced uniformly by environmental and task variables.

Adult↗
PubMed1993

The visibility of symbolic highway signs can be increased among drivers of all ages.

Visibility and comprehension of standard text, standard symbolic, and improved symbolic highway signs were compared among young, middle-aged, and elderly observers. The average distance at which standard symbolic signs could be identified was about two times that of text signs for all three age groups. The visibility distances of the improved symbolic signs, which were designed using an optical blur (i.e., low-pass) approach in order to avoid higher spatial frequencies, exceeded those of both text and standard symbolic signs. Visibility distance was decreased significantly among older drivers on some signs but not others. There were no significant age differences in the comprehension of symbolic signs. Acuity, a good predictor of visibility distance of both text and standard symbolic signs, was only weakly related to the visibility distance of the improved symbolic signs. These findings demonstrate that low-pass symbolic signs have significant advantages in visibility over their test counterparts for all drivers.

Adult↗
PubMed1980

Imaginal vs perceptual scanning of a visual representation.

Imaginal and perceptual scanning were compared to determine whether the reaction time function obtained during imaginal scanning in previous studies is analogous to what would happen in the perceptual situation. Subjects scanned arrays of four digits which were either imagined of physically present. Monotonic increases in reaction time as a function of distance were found in both cases. However, the zero intercept of the reaction times was significantly faster for the perceptual scanning group, probably due to the easier access to the loci. The over-all similarity in the results might suggest that a common structure is employed to represent information from imaginal and perceptual sources.

Distance Perception↗
PubMed1989

Is locomotor distance estimation guided by visual imagery?

70 subjects were tested for their visual subscale scores on the Movement Imagery Questionnaire and also for their ability to walk, without vision, to a previously viewed target location 9 m away. Imagery ability was hypothesized to correlate with accuracy of "blind" target-directed walking which the literature suggests, without empirical support, is imagery-dependent. No support for this hypothesis was found. Low, medium, and high imagers showed no differences in ability to reproduce target distance accurately or consistently by walking the estimated distance without further visual updating. The results call into question whether task performance is imagery-based or whether subjects use alternative strategies to approach the target.

Adult↗
PubMed2003

Variation in black anti-white bias and target distancing cues: factors that influence perceptions of "ambiguously racist" behavior.

Experiment 1 indicated that when the White supervisor's negative treatment of a Black subordinate was unconstrained, participant race had no impact on attributions. Conversely, when the treatment was constrained, Black participants reported greater racist attributions than did White participants. Experiment 2 indicated that when the supervisor reported no response or a minimal negative response (i.e., indicating that he did not support his actions) after his negative treatment of the Black subordinate, Black participants reported greater racist attributions than did White participants. Conversely, when the supervisor's negative treatment was followed by a more extreme negative response, participant race had no impact on attributions. Experiment 3 indicated that Black participants were less likely than White participants to perceive a minimal negative response as reflecting a White supervisor's lack of support for his negative actions. Conversely, participant race had no impact on attributions of a Black supervisor's negative actions.

Adult↗
PubMed2006

A comparison of the reach-to-grasp movement between children and adults: a kinematic study.

In this study, the reach-to-grasp movement of 5-year-old children was compared to that of adults. Participants were required to reach out and grasp objects, with and without on-line visual feedback. Object size and distance were covaried in a within-subjects design and it was found that for both groups, grip formation and reach kinematics were affected by the manipulation of either variable. Although there are a large number of similarities, a few differences between the two groups emerge. For the reaching component, the children revealed a longer movement duration and deceleration time and a lower maximum height of wrist trajectory than in adults. For the grasp component, the children, in both the vision and no-vision condition, show a maximal finger aperture larger than the adults. Further, the children of this study were able to scale their grip aperture according to object size when visual feedback during the movement was lacking. These findings suggest that children adopt different strategies than adults when planning a reach-to-grasp movement on the basis of object size, distance, and the predictability of visual feedback. The results are discussed in terms of the neural mechanisms underlying hand action and how these mechanisms may not be fully developed by the age of 5.

Adult↗
PubMed1978

Social cues, cognitive style, error magnitude, and male performance on the Felt Figure Replacement Technique.

A series of studies was undertaken to determine possible factors contributing to low predictive utility for Felt Figure Replacement Technique (FFRT) scores from normal, adult males. It was first postulated that normal adult males, compared to normal adult females, are less sensitive to social cues present in the FFRT task. Twenty-six undergraduate males and the same number of undergraduate females were asked to replace both a) department store manikins, thought to be less abstract, and then b) felt figures. While task differences were obtained, these were not dependent on gender, nor did any overall gender differences occur for three types of replacement error. The second study involved 31 college males and 33 college females replacing both felt figures and a male and female confederate. It was assumed that differential attention to social cues would be more visible in this comparison. The general results were identical to the first study.

Cognition↗
PubMed2004

Overestimation of numerical distances in the left side of space.

Normal subjects presented with a middle number and two left- and right-sided outer numbers overestimate the numerical distance between the middle number and that positioned at its left side. Repetitive transcranial magnetic stimulation (rTMS) of the right posterior parietal cortex specifically counteracts this bias, suggesting that the mental representation of space defined by numbers is shifted toward the left side depending on a greater activity of the right hemisphere.

Adult↗
PubMed2002

Influence of final search direction on tactile line bisection in normal subjects.

BACKGROUND: Many variables influence the tactile bisection performance of normal subjects. Of these, studies that investigated the starting point effect have reported inconsistent results. OBJECTIVE: To determine if the final search direction rather than the initial search direction (starting point) may have an effect on tactile bisection performance, especially when subjects are making multiple searches. METHODS: The authors divided the experiment into single- and multiple-search tasks. Thirty-two blindfolded normal subjects were asked to indicate the midpoint of a rod after a one-way search (single-search task) or after two or more one-way searches (multiple-search task). In each task, the subject started on either end of the horizontally placed rods. The same procedure was also conducted with rods oriented vertically or radially. Therefore, there were six conditions (two starting points x three orientations). RESULTS: In the single-search task, there was a significant effect of starting point or movement direction in all six conditions, with biases occurring toward the starting point from the true midpoint (this is termed the "overshoot phenomenon"). In the multiple-search task, however, there was no significant effect of the starting point in all six conditions. Rather, biases depended on the final movement direction in five of the six conditions, occurring toward the starting point of the final search. CONCLUSION: Future research is needed to understand the mechanism of the overshoot phenomenon in tactile bisection by normal subjects and how the overshoot phenomenon influences patients with neglect.

Adult↗
PubMed2003

Honeybee navigation: properties of the visually driven 'odometer'.

Recent work has revealed that honeybees determine distance flown by gauging the extent to which the image of the environment moves in the eye as they fly toward their destination. Here we examine the properties of this visually driven 'odometer', by training bees to fly to a feeder in a tunnel lined with a range of different visual patterns, and analysing their dances when they return to the hive. We find that the odometric signal is relatively unaffected by variations in the contrast and spatial frequency content of the patterns. Furthermore, a strong signal is generated even when the walls or the floor of the tunnel provide only weak optic-flow cues. Thus, distance flown is measured by a visually driven odometer that is surprisingly robust to variations in the texture or sparseness of the visual environment through which the bee flies.

Animals↗