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 217 records · Page 12Linked to original sources
PubMed1990

Visual alleys as a function of instructions under informative and reduced conditions of viewing.

Three experiments were designed to explore parallel and distance alleys as a function of instructions (apparent and objective) under three different distance-cue conditions. The main findings were that (1) the alleys for the apparent instructions were positioned closer to the median plane than those for the objective instructions, (2) in an indoor setting, the parallel and distance alleys were not different under either the apparent or the objective instructions, and (3) in an outdoor setting, the parallel alley lay inside the distance alley under both the apparent and the objective instructions. On the basis of comparison with some of the previous alley studies, it is suggested that exact control of instructions will not produce great discrepancy between the parallel and the distance alleys that were constructed indoors.

Adult↗
PubMed1995

Influence of flicker on perceived size and depth.

Previous research (e.g., Wong & Weisstein, 1984a, 1985) has shown that flickering stimuli appear to be more distant than nonflickering stimuli at the same physical distance. Given this relation between flicker and perceived depth, inappropriate constancy scaling theories predict that flickering stimuli should be perceived as larger than nonflickering ones. In contrast, links between flicker and motion perception suggest that flickering stimuli should be perceived as smaller than nonflickering ones. Two experiments tested these contrasting predictions. In Experiment 1, 22 subjects compared flickering and nonflickering vertical lines and reported that the flickering stimulus appeared significantly smaller than the nonflickering one. In Experiment 2, 21 subjects reported that the stimuli used in Experiment 1 produced depth effects similar to those reported in previous experiments: flickering stimuli were perceived as more distant than nonflickering ones. The observed effect of flicker on perceived size was contrary to predictions from inappropriate constancy scaling theory, but consistent with views that motion and flicker are processed by the same pathway.

Adolescent↗
PubMed1984

Visually perceiving distance: a comment on Shebilske, Karmiohl, and Proffitt (1983).

Shebilske, Karmiohl, and Proffitt (1983) interpret their data as showing that (a) the reference tonus level of the extraocular muscles controlling vergence is affected by everyday conditions of close viewing, and (b) this naturally induced phoria affects the visual perception of distance under natural viewing conditions. We note that these interpretations do not fully concur with the data presented--for example, the second conclusion favorably conflates partial results from two separate experiments--and we identify a number of confoundings that reduce the likelihood that the reported inaccuracies in distance judgments were due to variations in efference.

Distance Perception↗
PubMed1987

Art and the oculomotor system: perspective illustrations evoke vergence changes.

When a painting or drawing is viewed monocularly and fixation alternated between points that are at different implied distances from the observer, the covered eye usually makes vergence movements that are directionally appropriate for the indicated depth differences. These vergence changes evoked by perspective artwork vary greatly in magnitude and consistency from one illustration to the next: some drawings and paintings lead to convergence-divergence changes smaller than would be appropriate for the illustrated content, if seen from the implied viewing distance; others are supernormal stimuli, evoking inappropriately large vergence changes in all observers tested.

Adolescent↗
PubMed1986

Shape constancy and polar perspective.

The distortion of polar perspective depends on the depth of the tridimensional shape and on the observation distance. In four experiments using 54 undergraduates as subjects, we found that a compensation process which takes depth and observation distance into account corrects for such distortions. Compensation was demonstrated in experiments in which deceptive information on depth and on observation distance was provided. The result was distortions of the perceived shapes that would be expected if compensation were based on the deceptive information.

Cues↗
PubMed1976

An investigation of the relationship between viewing condition and preference for true and modified linear perspective and adults.

In four experiments, pictures varying in degree of perspective convergence from linear to parallel were observed under the following conditions: at an arbitrary station point, at correct station points, and with unconstrained view. Adults were asked to rank the pictures from the most to least natural and realistic-looking picture or from the most to the least accurate drawing. Subjects nearly always chose the parallel perspective pictures as most preferred and the linear perspective pictures as least preferred. Intermediate degrees of convergence were ranked accordingly. Results were interpreted in light of an argument for a pictorial station poing independent of the correct center of projection for a picture. Since this station point was calculated to be at a distance at least 10 times as great as the object is large, its assumption for pictorial viewing was termed the "Zoom "effect.

Adult↗
PubMed1979

Estimation of distances of recorded sounds presented through headphones.

Intermittent sounds generated at 270 degrees azimuth and from distances ranging from 2 to 10 feet were recorded on magnetic tape and played back to listeners via headphones. Loudness cues for relative distance were eliminated at the time of recording. Listeners were required to estimate the apparent distance of the recorded sounds when heard monoaurally and binaurally. Most subjects estimated the order of distances correctly. Distance estimations were as proficient when listening monaurally as when listening binaurally. Performance was more accurate for high-pass (greater than 4.0 kHz) noise bursts than for low-pass (less than 1.0 kHz) noise bursts. In a second study, broad-band noise bursts were recorded from azimuthal positions of 360 degrees, 330 degrees, 300 degrees and 270 degrees again at distances ranging from 2 to 10 feet. Estimations of the distances of the sounds, presented via headphones, were most proficient when azimuthal position of the original stimuli was 330 degrees.

Acoustic Stimulation↗
PubMed1984

[Binocular functions in unilateral pseudophakia].

71 patients (average age 64 years) were examined for binocular vision after unilateral posterior chamber lens implantation. Average visual acuity in the pseudophacic as well as the phacic eyes was 0.8. Intact stereoscopic dose-up and long-distance vision was found in 85% of the cases. Patients with vertical phorias or moderately decreased visual acuity more often presented impaired binocular functions. Further investigations will be carried out.

Aged↗
PubMed1990

Perceptual information for the timing of interceptive action.

Time-to-contact is an important quantity for controlling activities which involve the timing of interactions with objects and surfaces in motion relative to an observer. Two alternative means for obtaining perceptual information that might be used to obtain the time-to-contact required to correctly time an interaction have been contrasted: a method based on the perception of distance and velocity, and a method due to Lee involving a perceptual variable called tau. A monocular version of the first method is presented and shown to place a highly unrealistic and arbitrary limitation on the capabilities of the visual system. The second method is reviewed and its limitations discussed. Several means by which these limitations can be overcome are presented. Recently reported results from experiments which involved catching self-luminous balls in the dark are interpreted in terms of timing information available to the subject, and the notions of intermodal and multimodal timing information are introduced. Finally, the possibility that timing information is available to an observer which does not involve the variable tau is considered. It is concluded that many questions regarding the perception of time-to-contact remain unresolved and that much empirical research remains to be done.

Acceleration↗
PubMed1988

Depth resolution in the pigeon.

Pigeons possess a binocular visual field and a retinal region of higher cellular density pointing to the center of this overlap. These features and the precision of pecking behavior suggest that in this lateral-eyed bird cues other than monocular ones might participate in depth judgements. Pigeons were trained with an operant procedure to discriminate between luminous points differing in depth which appeared to the observer as floating in the dark. The accuracy of depth judgements was found to be a function of the ratio between the interstimulus distance and the mean eyes-to-stimulus distance. In a first test (experiment I) no external binocular disparity cues were available, the animal only seeing one luminous point at a time (near or far). In a second test (experiment II) where binocular disparity cues were available, the animal having this time to discriminate a pair of points placed at equal depth from a pair placed at unequal depths, only one pair being visible at a time, depth resolution did not improve. This suggests that, at least within the range of distances explored, the pigeon has no stereoscopic vision. Notwithstanding this, binocular cues do play a role, since when tests were done comparing binocular with monocular viewing (experiment III), monocular depth resolution was significantly worse.

Animals↗
PubMed1992

The role of binocular vision in prehension: a kinematic analysis.

This study examined the contribution of binocular vision to the control of human prehension. Subjects reached out and grasped oblong blocks under conditions of either monocular or binocular vision. Kinematic analyses revealed that prehensile movements made under monocular viewing differed substantially from those performed under binocular conditions. In particular, grasping movements made under monocular viewing conditions showed longer movement times, lower peak velocities, proportionately longer deceleration phases, and smaller grip apertures than movements made under binocular viewing. In short, subjects appeared to be underestimating the distance of objects (and as a consequence, their size) under monocular viewing. It is argued that the differences in performance between the two viewing conditions were largely a reflection of differences in estimates of the target's size and distance obtained prior to movement onset. This study provides the first clear kinematic evidence that binocular vision (stereopsis and possibly vergence) makes a significant contribution to the accurate programming of prehensile movements in humans.

Adult↗