Search results for "distance perception"
showing 10 items of 24 documents
A screen for constituents of motor control and decision making in Drosophila reveals visual distance-estimation neurons
2016
AbstractClimbing over chasms larger than step size is vital to fruit flies, since foraging and mating are achieved while walking. Flies avoid futile climbing attempts by processing parallax-motion vision to estimate gap width. To identify neuronal substrates of climbing control, we screened a large collection of fly lines with temporarily inactivated neuronal populations in a novel high-throughput assay described here. The observed climbing phenotypes were classified; lines in each group are reported. Selected lines were further analysed by high-resolution video cinematography. One striking class of flies attempts to climb chasms of unsurmountable width; expression analysis guided us to C2 …
The effect of furnishing on perceived spatial dimensions and spaciousness of interior space
2014
Despite the ubiquity of interior space design, there is virtually no scientific research on the influence of furnishing on the perception of interior space. We conducted two experiments in which observers were asked to estimate the spatial dimensions (size of the room dimensions in meters and centimeters) and to judge subjective spaciousness of various rooms. Experiment 1 used true-to-scale model rooms with a square surface area. Furnishing affected both the perceived height and the spaciousness judgments. The furnished room was perceived as higher but less spacious. In Experiment 2, rooms with different square surface areas and constant physical height were presented in virtual reality. Fu…
A Slippery Slope: Estimated Slant of Hills Increases with Distance
2014
The slopes of hills tend to be greatly overestimated. Previous studies have found that slope estimates are significantly greater when estimated verbally than with a proprioceptive measure. It has yet to be determined whether these estimates are made for the entire extent of the slope, or whether the estimates in closest proximity are estimated using a different process. Since some parietal cortex neurons respond differently to objects within arm's reach, short-distance slope estimation may utilize these or analogous neurons. Alternatively, greater implied effort might make longer slopes seem steeper. We determined that both verbal and proprioceptive reports of slope are overestimates that …
Associations of reading posture, gaze angle and reading distance with myopia and myopic progression
2016
Purpose To study the associations of habitual reading posture, gaze angle in reading and reading distance with myopia and changes in myopia among myopic children. Methods A total of 240 myopic schoolchildren (mean age 10.9 years), with no previous spectacles, were recruited during 1983–1984 to a randomized 3-year clinical trial of bifocal treatment of myopia. Three annual examinations with subjective cycloplegic refraction were conducted for 237–238 subjects. A further examination was conducted at the mean age of 23.2 years for 178 subjects. Habitual reading posture was elicited by questionnaire at study outset. Reading distance was measured with a Clement Clark accommodometer and gaze angl…
The impact of rear-view mirror distance and curvature on judgements relevant to road safety
2011
We report two experiments that investigate the impact of rear-view mirror distance and curvature on distance, spacing, and time-to-contact (TTC) judgements. The variation in mirror distance had a significant effect on TTC judgements, but only marginally influenced distance and spacing estimations. As mirror distance increased, TTC was overestimated, which is potentially dangerous. Control conditions with identical visual angles across different mirror distances revealed that effects were not solely caused by variation in visual angle. The impact of mirror curvature moderated the effect. While observers were unable to compensate for the mirror distance effect, they could do so for the distor…
Convex rear view mirrors compromise distance and time-to-contact judgements
2007
Convex rear view mirrors increasingly replace planar mirrors in automobiles. While increasing the field of view, convex mirrors are also taken to increase distance estimates and thereby reduce safety margins. However, this study failed to replicate systematic distance estimation errors in a real world setting. Whereas distance estimates were accurate on average, convex mirrors lead to significantly more variance in distance and spacing estimations. A second experiment explored the effect of mirrors on time-to-contact estimations, which had not been previously researched. Potential effects of display size were separated from effects caused by distortion in convex mirrors. Time-to-contact est…
Overestimation of numerical distances in the left side of space
2004
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.
The remapping of time by active tool-use
2015
Multiple, action-based space representations are each based on the extent to which action is possible toward a specific sector of space, such as near/reachable and far/unreachable. Studies on tool-use revealed how the boundaries between these representations are dynamic. Space is not only multidimensional and dynamic, but it is also known for interacting with other dimensions of magnitude, such as time. However, whether time operates on similar action-driven multiple representations and whether it can be modulated by tool-use is yet unknown. To address these issues, healthy participants performed a time bisection task in two spatial positions (near and far space) before and after an active …
Surface Lightness Influences Perceived Room Height
2010
Surprisingly little scientific research has been conducted on the effects of colour and lightness on the perception of spaciousness. Practitioners and architects typically suggest that a room's ceiling appears higher when it is painted lighter than the walls, while darker ceilings appear lower. Employing a virtual reality setting, we studied the effects of the lightness of different room surfaces on perceived height in two psychophysical experiments. Observers judged the height of rooms varying in physical height as well as in the lightness of ceiling, floor, and walls. Experiment 1 showed the expected increase of perceived height with increases in ceiling lightness. Unexpectedly, the perce…
Measuring Perceived Ceiling Height in a Visual Comparison Task
2017
When judging interior space, a dark ceiling is judged to be lower than a light ceiling. The method of metric judgments (e.g., on a centimetre scale) that has typically been used in such tasks may reflect a genuine perceptual effect or it may reflect a cognitively mediated impression. We employed a height-matching method in which perceived ceiling height had to be matched with an adjustable pillar, thus obtaining psychometric functions that allowed for an estimation of the point of subjective equality (PSE) and the difference limen (DL). The height-matching method developed in this paper allows for a direct visual match and does not require metric judgment. It has the added advantage of pro…