PubMed Health⌕ Search

Biomedical subjects

J J Rieser

Publications and source records attributed to J J Rieser.

7 recordsLinked to original sources
PubMed1992

Visual experience, visual field size, and the development of nonvisual sensitivity to the spatial structure of outdoor neighborhoods explored by walking.

When places are explored without vision, observers go from temporally sequenced, circuitous inputs available along walks to knowledge of spatial structure (i.e., straight-line distances and directions characterizing the simultaneous arrangement of the objects passed along the way). Studies show that a life history of vision helps develop nonvisual sensitivity, but they are unspecific on the formative experiences or the underlying processes. This study compared judgments of straight-line distances and directions among landmarks in a familiar area of town by partially sighted persons who varied in types and ages of visual impairment. Those with early childhood loss of broad-field vision and those blind from birth performed significantly worse than those with early or late acuity loss and those with late field loss. Broad-field visual experience facilitates perceptual development by providing a basis for proprioceptive and efferent information from locomotion against distances and directions relative to the surrounding environment. Differences in the perception of walking, in turn, cause the observed differences in sensitivity to spatial structure.

Adolescent↗
PubMed1990

Visual perception and the guidance of locomotion without vision to previously seen targets.

Two experiments were performed to assess the accuracy and precision with which adults perceive absolute egocentric distances to visible targets and coordinate their actions with them when walking without vision. In experiment 1 subjects stood in a large open field and attempted to judge the midpoint of self-to-target distances of between 4 and 24 m. In experiment 2 both highly practiced and unpracticed subjects stood in the same open field, viewed the same targets, and attempted to walk to them without vision or other environmental feedback under three conditions designed to assess the effects on accuracy of time-based memory decay and of walking at an unusually rapid pace. In experiment 1 the visual judgments were quite accurate and showed no systematic constant error. The small variable errors were linearly related to target distance. In experiment 2 the briskly paced walks were accurate, showing no systematic constant error, and the small, variable errors were a linear function of target distance and averaged about 8% of the target distance. Unlike Thomson's (1983) findings, there was not an abrupt increase in variable error at around 9 m, and no significant time-based effects were observed. The results demonstrate the accuracy of people's visual perception of absolute egocentric distances out to 24 m under open field conditions. The accuracy of people's walking without vision to previously seen targets shows that efferent and proprioceptive information about locomotion is closely calibrated to visually perceived distance. Sensitivity to the correlation of optical flow with efferent/proprioceptive information while walking with vision may provide the basis for this calibration when walking without vision.

Adult↗
PubMed1989

Access to knowledge of spatial structure at novel points of observation.

Adults were asked to judge the self-to-object directions in a room from novel points of observation that differed from their actual point at times only by a rotation and at other times only by a translation. The results show for the rotation trials that the errors and latencies when a novel point was imagined were worse than the baseline responses from their actual points of observation, and the latencies varied as a function of the magnitude of the to-be-imagined rotation. For the translation trials, on the other hand, the errors and latencies when a novel point was imagined were comparable to the baseline responses from their actual point and did not vary significantly across the different imagined station points. The evidence indicates that subjects know the object-to-object relations directly, without going through the origin of a coordinate system. In addition, similarities in processing during imagination on the one hand, and perception and action on the other are discussed.

Adult↗
PubMed1988

Pointing at objects in other rooms: young children's sensitivity to perspective after walking with and without vision.

Locomotion alters the spatial structure of an observer's perspective, that is, the network of observer to environment distances and directions. The purpose of the present 6 experiments was to investigate the sensitivity of 12-48-month-olds to changes in perspective that are occluded from view by walls and by darkness. To assess sensitivity, children were shown a target object in one room, walked into an adjacent room and asked to point in the straight-line direction at the target. In Experiment 1, 42 12-48-month-olds were tested and results indicated that children older than 36 months responded by pointing straight at the occluded target, whereas younger children tended to point in the direction of their route away from the target. In Experiments 2-4, 24- and 48-month-olds were tested and results demonstrated that 48-month-olds were sensitive to the proprioceptive and to the visual-environmental cues for the changes in perspective structure. The 24-month-olds, however, responded by pointing straight toward the target when visual-environmental cues were absent, whereas they pointed in the direction of their route when they were present. In Experiments 5 and 6 additional 24-month-olds were tested to assess the effects of short-term training and of a continuous view of the target on responding in the presence of visual-environmental cues. The results indicated relatively early sensitivity to proprioceptive cues for changes in perspective and somewhat later sensitivity to appropriate visual-environmental cues under these conditions.

Child Development↗
PubMed1987

Mentally retarded and nonretarded adults' sensitivity to spatial structure.

The sensitivity of mentally retarded and nonretarded adults to changes in the structure of their perspectives when those changes are occluded from view during a walk was examined in two studies. Sensitivity was tested by starting participants at a target object located in one room of an unfamiliar office building, walking them via a circuitous path into a new room from which the target was occluded from view, and then asking them to aim a pointer straight at it. Direction judgments were collected across variations in the number of turns in the walk, spatial arrangements of rooms, amount of the subjects' attention available during the walk, and the availability of visual-environmental cues. Results indicate that retarded and nonretarded persons show similar levels of sensitivity to changes in perspective when they walk without visual-environmental cues (i.e., with eyes closed). In the presence of visual-environmental cues, however, the accuracy of nonretarded subjects increased dramatically whereas the retarded subjects did not improve at all. The similarities and differences in performance are related to differences in the perceptual learning thought to mediate use of proprioceptive cues and the inferential processes thought to mediate use of visual-environmental cues.

Adult↗
PubMed1986

Sensitivity to perspective structure while walking without vision.

Experiments are reported of the nonvisual sensitivity of observers to their paths of locomotion and to the resulting changes in the structure of their perspectives, ie changes in the network of directions and distances spatially relating them to objects fixed in the surrounding environment. In the first experiment it was found that adults can keep up to date on the changing structure of their perspectives even in the absence of sights and sounds that specify changes in self-to-object relations. They do this rapidly, accurately, and, according to the subjects' reports, automatically, as if perceiving the new perspective structures. The second experiment was designed to investigate the role of visual experience in the development of sensitivity to occluded changes in perspective structure by comparing the judgments of sighted adults with those of late-blinded adults (who had extensive life histories of vision) and those of early-blinded adults (who had little or no history of vision). The three groups performed similarly when asked to judge perspective while imagining a new point of observation. However, locomoting to the new point greatly facilitated the judgments of the sighted and late-blinded subjects, but not those of the early-blinded subjects. The findings indicate that visual experience plays an important role in the development of sensitivity to changes in perspective structure when walking without vision.

Adolescent↗