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PubMed1980

Effect of distance on heterochromatic matching.

The brightness of colors in a number of paintings by Francis Pratt appeared to vary as a function of the viewing distance. These pictures were composed of narrow strips of different colors varying in brightness and saturation. Five experiments were undertaken to replicate and study this effect under controlled conditions using heterochromatic brightness matching of various pairs of colored stimuli. The subjects were first-year students in psychology, participating as a course requirement. The number of subjects varied in the different experiments, between 6 and 9. The relative brightness of blue as compared to red, orange, and yellow-green varied as a function of viewing distance. The relative brightness of the blue decreased as distance increased. By varying the physical size of the stimuli it was possible to keep the angle subtended at the retina constant for two distances and the effect remained. Any explanation must therefore account for the finding that the effect is not due to the apparent size of th stimuli.

Color Perception↗
PubMed1982

Distance cues and depth avoidance on the visual cliff.

The study tested the hypothesis that depth avoidance in chicks is a specific case of general aversion to far patterns. Using a modified visual cliff, 192 male chicks less than 24 hr. old were on one side presented vertical patterns at varying distances from the centerboard and on the other side either a shallow or deep pattern. Control data indicated that, when two vertical patterns are presented on an opaque surface, chicks will descend to the nearer pattern and that this is motivated by aversion to the far pattern rather than attraction to the near one. Further data showed, however, that when a vertical pattern appeared at varying distances on one side of the centerboard and either a shallow or deep pattern appeared on the other, chicks avoided the side with depth at all distances of the vertical pattern. Depth avoidance in chicks then is not mediated by distance cues. While these may influence descent from a centerboard to an opaque surface, avoidance of depth overrides them on the visual cliff.

Animals↗
PubMed1985

Social distance and behavioral attributes of developmentally handicapped and normal children.

20 behavioral attributes predicting social distance were examined among 101 junior high school students in six classrooms. The sample included 8 developmentally handicapped students, of whom at least one of each was mainstreamed into each classroom. Subjects were predominantly white, middle-class, suburban midwesterners. A sociometric nomination measure was used to obtain behavioral attribute profiles of the students which were then used to predict a psychometric measure of social distance. Handicapped students were not more socially distant than their normal peers. Factor analysis of the 20 behavioral attributes yielded four factors, three of which were significant predictors of classroom social distance, accounting for better than half the variance in social distance. These were described as Incompetent/Unassertive, Positive/Active/Assertive, and Passive/Unassertive. Social rejection in mainstreamed classrooms is more a function of perceived behavioral attributes than the label developmentally handicapped.

Adolescent↗
PubMed1999

Standing distance in climbability of stairs.

The purpose of this experiment was to make a preliminary examination of the distance one needs to stand from a stair to successfully climb up without using arms for support. Using an adjustable stair structure to create different heights of risers, a group of 10 tall and of 10 short participants made perceptual judgments and physical attempts at heights that represented 83% and 93% of each group's mean leg length. Choice of maximum and minimum distance from the stair was measured for each participant. Analysis showed that perceptual judgments and physical capabilities were highly correlated (tall: Pearson r = .92); short: Pearson r = .93). Moreover, the ability to climb the two heights depended on the standing distance from the stair. The findings suggest that standing distance may be a consideration in stair climbing and that stair height alone may not be sufficient to specify climbability.

Adult↗
PubMed2002

Influence of stimulus distance in implicit learning of spatial and nonspatial event sequences.

The serial reaction time task has been widely used to investigate implicit learning mechanisms. In the present study, we investigated the effect of stimulus distance on learning of a spatial sequence independent of a sequence of responses. Participants had to respond to objects appearing at four different locations. The objects were presented in a sequence of nine elements, whereas the location at which an object was presented followed a sequence of eight elements. Thus, the spatial and the object sequences were independent of each other. Four groups of subjects for whom the distances of the locations chosen to present objects on the computer screen (3 cm, 6 cm, 12 cm, or 22 cm) differed were tested. Only the nonspatial sequence was learned as indicated by enhanced response latencies in nonsequenced random blocks. Stimulus distance had no effect on the amount of sequence learning. Additional analyses for subgroups of subjects who did not show explicit knowledge of the sequences after completion of the task indicated that for implicit learners also, sequence learning was not influenced by stimulus distance. The results are discussed with respect to current theories of implicit serial learning.

Adolescent↗
PubMed2004

Perceived enclosure of space, angle above observer, and distance to boundary.

Most previous research suggests that the horizontal size of a space has a strong effect on the perception of enclosure, but Hayward and Franklin reported in 1974 that the main determinant of perceived enclosure was the ratio of boundary height (H) over the distance to boundary (D) rather than just the boundary height per se or distance per se. We attempted replication of that finding. Students (41 male, mean age=24.7 yr., SD=7.7) rated 16 images on a scale of open/enclosed. There was a strong effect on impressions of enclosure for angle above observer (r = .91), and this effect was larger than the effect of height (r = -.17), but there also was another strong effect for distance (r = -.68). Moreover, the effect of distance was dependent on angle above observer (r = -.52). Thus, partial replication was achieved, and a new relationship between the geometry of environments and perceived enclosure was identified.

Adult↗
PubMed1995

Influence of target distance and acceleration level on eye movements evoked by lateral acceleration steps.

Lateral eye movements produced by linear acceleration along the inter-aural axis were studied in 6 normal subjects. They were seated upright, whole-body restrained, and were exposed to randomised rightward/leftward steps of 0.05 g. 0.1 g, 0.24 g of 600 ms duration. When viewing earth-fixed targets at 30, 60 or 280 cm from their eyes, mainly pure compensatory slow-phase eye movements were evoked at latencies around 50 ms measured for the closest viewing distances. At onset, slow-phase amplitude was modulated by acceleration and target distance. When the subjects were stationary and pursued moving targets at similar distances and accelerations, latencies around 140 ms were observed, and catch-up saccades were frequently made. From these experiments, we defined the dynamics of the otolith-ocular reflex for various levels of acceleration and viewing distances.

Adult↗
PubMed2004

Development of prehension between 5 and 10 years of age: distance scaling, grip aperture, and sight of the hand.

The authors investigated whether 5- to 10-year-old children (N = 75) differ from adults (N = 12) in the developmental course of distance scaling and the adaptations to the inability to see the hand during prehension movements. The children reached under a surface and grasped and lifted an object suspended through it. All children scaled velocity appropriately for movement distance, both with and without sight of the hand. However, 5- to 6-year-old children did not increase grip aperture with increased distance, whereas older children and adults did. The older children and adults spent longer after peak deceleration when they could not see the hand, and maximum grip aperture (MGA) was larger, providing an increased safety margin. Children aged 5 to 6 spent the same amount of time between peak deceleration and grasp, whether or not they could see the hand, and they failed to increase MGA when they could not see the hand. Prehension in the younger children differed from that of older children in two ways: The younger children did not integrate reach and grasp over different distances and did not use visual information about hand position to optimize accuracy.

Adolescent↗
PubMed2006

Using verbal and blind-walking distance estimates to investigate the two visual systems hypothesis.

Verbal estimates of egocentric distance are usually too short at distances greater than several meters, yet blindfolded walking to previously viewed targets can be surprisingly accurate. We present evidence from three experiments for the existence of two visual pathways with differentencodings of perceived egocentric distance. We found that (1) blind-walking estimates of egocentric distance are consistently more accurate than verbal reports; (2) an indoor versus outdoor environment selectively influences verbal reports; and (3) wearing prism lenses, which displace the visual field vertically, selectively influences the blind-walking estimates. We interpret these results in terms of the two visual systems hypothesis.

Adolescent↗
PubMed2004

Distortions of distance and shape are not produced by a single continuous transformation of reach space.

We investigated whether distortions of perceived distance and shape could be captured by a single continuous one-to-one transformation of the underlying space. In Experiment 1, the participants reached to touch points around the perimeter of spherical targets viewed at five different distances, to yield simultaneous measures of perceived distance and shape. Different participants reached while using dynamic monocular, static binocular, or dynamic binocular vision. Thin plate spline (TPS) analysis was applied so as to transform a Cartesian grid in such a way as to carry the original target points to the mean reach locations. In all cases, discontinuities appeared in the transformed grid from folding of the space. In Experiment 2, the participants reached to points that lay at the same locus in reach space, but on different portions of the visible target spheres (e.g., front vs. side). The participants reached to different locations when the points were different with respect to shape (e.g., front vs. side) but reached to the same locations when the points were the same with respect to shape (left vs. right side). TPS analysis revealed discontinuities from holes torn in the underlying space. The results show that perceived distance and perceived shape entail different distortions and cannot be captured by a single continuous transformation of reach space.

Adult↗
PubMed2003

Differentiating location- and distance-based processes in memory for time: an ERP study.

Memory for the time of events may benefit from reconstructive, location-based, and distance-based processes, but these processes are difficult to dissociate with behavioral methods. Neuropsychological research has emphasized the contribution of prefrontal brain mechanisms to memory for time but has not clearly differentiated location- from distance-based processing. The present experiment recorded event-related brain potentials (ERPs) while subjects completed two different temporal memory tests, designed to emphasize either location- or distance-based processing. The subjects' reports of location-based versus distance-based strategies and the reaction time pattern validated our experimental manipulation. Late (800-1,800 msec) frontal ERP effects were related to location-based processing. The results provide support for a two-process theory of memory for time and suggest that frontal memory mechanisms are specifically related to reconstructive, location-based processing.

Distance Perception↗
PubMed2005

The wall inside the brain: overestimation of distances crossing the former Iron Curtain.

A study of distance estimations between German cities investigated the organization of mental maps and their specific deviations from reality. Potential factors for the deviation of mental maps from reality are physical barriers, emotional involvement, and semantic unity. Distance estimations between cities situated in different former parts of Germany (East or West) were systematically overestimated compared to distances of cities located in the same parts of Germany. This trend was strengthened when participants had a negative attitude toward the reunification of Germany. The impact of these results is far reaching, because overestimated distances between both German parts indicate that there still exists a mental gap between East and West--even in young people--15 years after the German reunification.

Adult↗
PubMed2005

Is size perception based on monocular distance cues computed automatically?

The study reported here examined whether size perception based on monocular distance cues is computed automatically. Participants were presented with a picture containing distance cues, which was superimposed with a pair of digits differing in numerical value. One digit was presented so as to be perceived as closer than the other. The digits were of similar physical size but differed in their perceptual size. The participants' task was to decide which digit was numerically larger. It was found that the decision took longer and resulted in more errors when the perceptual size of the numerically larger digit was smaller than the perceptual size of the numerically smaller digit. These results show that perceived size affects performance in a task that does not require size or distance computation. Hence, for the first time, there is empirical support for the working assumption of the visual perception approach that size perception based on monocular distance cues is computed automatically.

Cues↗
PubMed1997

Holding an object one is looking at: kinesthetic information on the object's distance does not improve visual judgments of its size.

Visual judgements of distance are often inaccurate. Nevertheless, information on distance must be procured if retinal image size is to be used to judge an object's dimensions. In the present study, we examined whether kinesthetic information about an object's distance--based on the posture of the arm and hand when holding it--influences the object's perceived size. Subjects were presented with a computer simulation of a cube. This cube's position was coupled to that of a rod in the subject's hand. Its size was varied between presentations. Subjects had to judge whether the cube they saw was larger than, smaller than, or the same size as a reference. On some presentations, a small difference was introduced between the positions of the rod and of the simulated cube. When the simulated cube was slightly closer than the rod, subjects judged the cube to be larger. When it was farther away, they judged it to be smaller. We show that these changes in perceived size are due to alterations in the cube's distance from the subject rather than to kinesthetic information.

Distance Perception↗
PubMed1999

Distance education: has technology become a threat to the academy?

Recent discussions regarding technology-assisted distance education have given rise both to enthusiastic predictions about how this form of instruction will transform higher educational institutions and to widespread fears about the threats that this technology poses to the student-teacher relationship and to the profession of university teacher in general. A review of opinions regarding distance education and computer technology in academia suggests a continuum of positions, ranging from the expectation that dramatic and even cataclysmic changes will lead to the eventual dissolution of the university to an envisioning of only minor changes in the academy's objectives and methods. In the present paper, this continuum is used as an organizing scheme to present the positions of several well-known advocates for and against the use of distance education and information technology. It is argued that the accreditation process will ultimately determine the degree to which distance education replaces traditional classroom instruction and that this process can be influenced by faculty involvement in decisions about the use of technology in the classroom.

Accreditation↗
PubMed2006

Environmental context influences visually perceived distance.

What properties determine visually perceived space? We discovered that the perceived relative distances of familiar objects in natural settings depended in unexpected ways onthe surrounding visual field. Observers bisected egocentric distances in a lobby, in a hallway, and on an open lawn. Three key findings were the following: (1) Perceived midpoints were too far from the observer, which is the opposite of the common foreshortening effect. (2) This antiforeshortening constant error depended on the environmental setting--greatest in the lobby and hall but nonsignificant on the lawn. (3) Context also affected distance discrimination; variability was greater in the hall than in the lobby or on the lawn. A second experiment replicated these findings, using a method of constant stimuli. Evidently, both the accuracy and the precision of perceived distance depend on subtle properties of the surrounding environment.

Adult↗
PubMed1992

Haptic probing: perceiving the length of a probe and the distance of a surface probed.

Knowing about the properties of objects by wielding them and knowing about the distances of surfaces by striking them with objects as probes are examples of dynamic or effortful touch. Six experiments focused on the invariant mechanical parameters that couple the time-varying states (displacements, velocities) of hand-held rods to the time-varying torques and forces imposed upon them by wielding and probing. There were three major conclusions. First, when a probe is wielded without contact, perceived probe length is a function of the probe's rotational inertia; however, with contact, perceived probe length is affected by the rotational inertia and the distance of the point of contact from the probe's center of percussion. Second, when a surface is struck with a probe, perceived surface distance is affected by the probe's rotational inertia and the angle of inclination of the probe at contact. Third, under seemingly identical conditions of probing, either probe length or surface distance can be perceived selectively without confusion. Results were discussed in terms of haptic information, haptic attention, and the dynamics of probing.

Adult↗
PubMed1992

The interaction of perceived distance with the perceived direction of visual motion during movements of the eyes and the head.

A horizontally moving target was followed by rotation of the eyes alone or by a lateral movement of the head. These movements resulted in the retinal displacement of a vertically moving target from its perceived path, the amplitude of which was determined by the phase and amplitude of the object motion and of the eye or head movements. In two experiments, we tested the prediction from our model of spatial motion (Swanston, Wade, & Day, 1987) that perceived distance interacts with compensation for head movements, but not with compensation for eye movements with respect to a stationary head. In both experiments, when the vertically moving target was seen at a distance different from its physical distance, its perceived path was displaced relative to that seen when there was no error in perceived distance, or when it was pursued by eye movements alone. In a third experiment, simultaneous measurements of eye and head position during lateral head movements showed that errors in fixation were not sufficient to require modification of the retinal paths determined by the geometry of the observation conditions in Experiments 1 and 2.

Adult↗