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PubMedDate not supplied

A Web-based distance education course in nutrition in public health: case study.

BACKGROUND: Strict work timetables, personal and professional duties or an inability to be absent from home or work can all represent major constraints for those wishing to improve their professional skills. Within this context, the World Wide Web can allow people to conveniently follow distance courses from their homes. OBJECTIVE: To present an experience in the use of the Web in the continuing education of healthcare professionals in Brazil. METHODS: A Web-based distance education course in nutrition in public health was developed. The methodology was an adaptation of both problem-based and task-based learning. At the end of the course an evaluation questionnaire which covered the course s contents, the educational methodology and resources, the duration and schedule, and the use of the Web as a tool for distance education was given to the students. RESULTS: There were 83 on line registrations from 13 states, 73 of the applicants were female, 62 had a degree in nutrition and 18 were physicians. From these; eleven students from ten states were chosen: nine female nutritionists, two female physicians, and one male physician. Seven students completed the course, took and passed the final exam. Of the other four students, two failed to follow the schedule, one had health problems, and one did not obtain the minimal score for sitting the final exam. The students had a mean age of 35, and a mean of ten years in practice. They all stated that they were unable to attend a regular course, even though they felt that they needed to improve their professional skills. Most of them studied seven days a week for between two and four hours a day. The students also felt that their professional skills had improved and each reported having made changes in their practice as a result of their participation. The students approved of the course s contents, methodology and resources, however they were divided about its duration. The Web as a tool in distance education was approved by the students. If it was not for the Web they could not have taken part in a continuing education program. All students said they would attend another virtual course, if available. Even though most of them did not have difficulty adapting to the virtual environment, they did feel that an adaptation period would be of value. CONCLUSIONS: A Web-based course may be more effective than other distance education methodologies because it is more interactive and dynamic. On-line material can be constantly reviewed and updated, and the students can have the opportunity to submit commentaries or questions directly to the teaching staff. A Web-based course also allows the students to go beyond the course content as they learn how to search and take advantage of the huge resources of information available on the Internet.

Adult↗
PubMed1975

Relation between judged and physical distance in multicue conditions as a function of instructions and tasks.

Using a rod adjustable in distance 48 Os produced equal depth intervals along a floor of a visual alley (interval reproduction) or bisected a given depth interval into two equal parts (bisection). Also, verbal reports were obtained of a depth interval located at a near and farther distance from O (absolute judgments). Two kinds of instructions, "apparent" and "objective," were used with different Os with each of the three tasks. There was an over-all tendency (p = .05 on two of three tasks) for apparent instructions to produce less over-constancy or more under-constancy of distance than that produced by objective instructions. This tendency is consistent with a cognitive interpretation of over-constancy of distance. Clear over-constancy was obtained only by the combination of objective instructions and the bisection task. Clear under-constancy was obtained only by the combination of apparent instructions and the method of absolute judgments. The reason for the effect of task on magnitude of distance constancy is not understood.

Cognition↗
PubMed1977

Use of distance and location in short-term motor memory.

A retroactive interference paradigm was used to determine whether kinesthetic distance, location, or distance and location cues are used at recall of a blind, simple linear movement. Students performed interpolated movements which varied distance and location cues separately or jointly. Relative to a rest condition, joint distance and location interpolation produced significant interference while no significant interference was found for interpolation of individual distance or location. The results were interpreted as supporting the involvement of multiple kinesthetic cues in the establishment of memorial representations of motor movements.

Cues↗
PubMed1978

Effect of perspective and slant on perception of apparent size and distance.

An experiement was performed to re-examine the role of linear perspective and floor slant on apparent size and distance scales. Misleading perspective cues did not alter the observers' apparent distance scales but did influence the absolute magnitude of distance judgments; floor slant exerted little influence on apparent distance scales or the absolute magnitude of distance judgments. Neither perspective nor slant manipulation reliably affected apparent size scales or exerted more than a minor influence on the absolute magnitude of size judgments.

Cues↗
PubMed1982

Scaling apparent distance in a large open field: presence of a standard does not increase the exponent of the power function.

Apparent distance in a large open field was scaled by the method of magnitude estimation with or without a standard distance present. The presence of the standard did not increase the exponent of the power law. The average exponent of the power function relating judged to physical distance was .87. The results are consistent with those of other studies showing that apparent distance is a decelerating function of actual distance in a natural outdoor setting.

Adolescent↗
PubMed1983

Individual differences in distance estimation: comparison of judgments in the field with those from projected slides of the same scenes.

This study was designed to determine the comparative accuracy with which trained and untrained observers could judge distances to a target and to assess the correspondence of those judgments with other judgments, by the same observers, from photographic slides of the same target and scene at identical viewing distances. 9 experienced and 15 untrained observers estimated distances ranging from 600 to 1550 m in 50-m increments. Photographic slides were made of the target at each distance and, 1 mo. later, observers made the same judgments from the slides. It was found that averages of the group's judgments in the field very closely approximated true target distances. However, judgments of the individual observers were so erratic and inaccurate as to render questionable the interpretation of those averages. In addition, while the averages of the group indicated that judgments from two-dimensional slides could be substituted fro three-dimensional real-world judgments, detailed analysis of the individual observers' performances dramatically contradicted this conclusion.

Discrimination Learning↗
PubMed1986

Distance perception in photographic displays of natural settings.

Distance perception of depicted objects was examined as a function of photographic perspective. 24 subjects viewed slides of outdoor scenes and directly estimated the distances to specified objects. Perspective was manipulated by photographing each scene with lenses of four different focal lengths: 48 mm, 28 mm, 24 mm, and 17 mm. Distance perception along the pictorial depth plane (z-axis) was systematically transformed by changing the photographic perspective: the shorter the focal length of the camera lens, the greater the perceived distance. Perceived distance between objects along the lateral plane (x-axis) was unaffected by changes in lens focal length.

Cues↗
PubMed1986

Stability of individual psychophysical functions for perceived distance in natural indoor and outdoor settings.

Exp. 1 examined correlations of the power functions exponents for individual observers, for apparent distance in a natural indoor setting, obtained for a group of 9 observers over 5 experimental sessions separated by intersession intervals that varied from 1 day to 9 mo. Stable individual differences in the exponent of the psychophysical power law were shown. Intercorrelations of subjects' exponents were positive and reliable with 1 day between sessions and 9 mo. In Exp. 2 the estimates of apparent distance were made by 5 independent groups of 10 observers each, tested and retested at different intersession intervals. There were 5 intervals of 1 day to 9 mo. Fair temporal stability of psychophysical power function exponents was observed in most groups. In Exp. 3 psychophysical power functions were obtained from magnitude estimates of apparent distance in a natural outdoor setting. The same 10 observers were tested and then retested after 1 day and again after 1 yr. Significant correlations for both intersessions intervals indicated consistent and persisting individual differences. Taken together Exps. 1, 2, and 3, regardless of the environment in which distance estimates were performed, clearly demonstrate that power functions are repeatable, enduring, and characteristic of individuals. In addition, the mean exponents were in reasonable agreement with other reported apparent distance exponents obtained in both settings.

Adult↗
PubMed1989

Effect of starting position on reproduction of movement: further evidence of interference between location and distance information.

Two experiments done with a short-term memory paradigm examined the influence of shifts in the starting position on the reproduction of kinesthetic location (Exp. 1) and on distance cues (Exp. 2). We assessed possible causes of the systematic pattern of undershooting and overshooting as related to the shift in the starting position. In each experiment, two groups of 10 students were given 25 trials, and each had criterion and reproduction tasks involving linear-positioning movements with a 10-sec. retention interval. Each experiment had two independent variables, the group of subjects and the shift in the starting position. The two groups differed in the possible sources of information, the distance moved (Exp. 1) or the end-location (Exp. 2), which were assumed to cause undershooting and overshooting during reproduction. Analysis showed that the information about the distance moved may produce undershooting and overshooting in reproduction of the end-location (Exp. 2). Also, the information about the end-location may produce undershooting and overshooting in reproduction of the distance moved (Exp. 2). The findings were further evidence of interference between location and distance cues in motor short-term memory.

Cues↗
PubMed2002

Apparent distance in actual, three-dimensional video-recorded, and virtual reality.

This study examined how well reality was reproduced in several conditions of virtual reality, by mutually comparing the perception of distance in actual 3-dimensional space and 3-dimensional video-recorded space. Apparent distances in both indoor and outdoor situations were estimated by 10 adolescents. Analysis showed that relations between apparent distance and physical distance in the actual spaces both in indoor and outdoor situations are described by 0.95 and 1.01 power exponents, respectively. On the other hand, the underestimations of the apparent distance are shown in the 3-dimensional video-recorded and the virtual reality spaces both in indoor and outdoor situations whose exponents ranged from .53 to .80.

Adult↗
PubMed1995

Psychological size and distance in the relationships of adult children of alcoholics with their parents.

Adult children of alcoholics' (n = 68) perceptions of their relationships with parents were compared with those of a control sample (n = 37) to examine independent and joint influences of interpersonal status and affect on family dynamics. Visual metaphors for relationships using circle drawings and a status-affect rating scale from the Grasha-Ichiyama Psychological Size and Distance Scale were employed. Compared with the control group, adult children of alcoholics drew smaller circles to represent themselves, i.e., indicating less interpersonal status, only when assessing their relationships with their fathers. Analyses of status-affect ratings showed that the drawings of smaller circles reflected feeling less competent, i.e., having less personal knowledge and expertise, rather than perceptions of being submissive in the relationship. The distance drawn between the circles of adult children of alcoholics and their parents, i.e., psychological distance, was much larger than that of the control group. Ratings showed that perceptions of a negative emotional climate and submissiveness together accounted for 25% of the unique variance in predicting psychological distance. Perceptions of being submissive, however, were not associated with perceptions of psychological distance among adult children of nonalcoholic parents.

Adult↗
PubMed2006

Distance education vs face-to-face classes: individual differences, course preferences and enrollment.

To understand better students' preferences for enrollment in distance education over face-to-face courses, the individual difference variables of sex, age category, class level, work status, number of distance education courses taken, frequency of computing technology usage, comfort with course management software, and comfort with computing technology were examined. Analysis indicated that older students, women, and those who work full time were more likely to enroll in distance education courses. Those who had taken the most distance education courses in the past and women were more likely to express a stated preference for distance education over face-to-face classes.

Adult↗
PubMed1995

Uncertainty in estimating distances from memory.

Magnitude estimations involving spatial characteristics, such as distance, typically show a compressive function when estimates are made from memory. In particular, as the magnitude of a property grows larger and larger, estimates become more and more inaccurate, with increasing underestimates of the actual magnitude. Previous theories have attempted to explain this difference by supposing that magnitude estimation was accomplished through a reperceptual process, in which the errors of perception are magnified, or a transformation process, in which the memory trace undergoes a consistent alteration toward a more schematic form. The present experiments present evidence in support of an uncertainty hypothesis. When subjects are uncertain of the actual value of a distance, they are forced to guess on the basis of the mean distance they encountered, because they are unable to retrieve the information accurately. When they can retrieve the information, they are more certain and their estimates are more accurate. This hypothesis was also extended to integrative conditions in which the subjects were presented with the stimulus display in a piecemeal fashion. In these cases, distance estimates were derived by combining spatial representations. This method of presentation caused distance estimates to become less accurate.

Attention↗
PubMed2001

Distance perception mediated through nested contact relations among surfaces.

In complex natural scenes, objects at different spatial locations can usually be related to each other through nested contact relations among adjoining surfaces. Our research asks how well human observers, under monocular static viewing conditions, are able to utilize this information in distance perception. We present computer-generated naturalistic scenes of a cube resting on a platform, which is in turn resting on the ground. Observers adjust the location of a marker on the ground to equal the perceived distance of the cube. We find that (1) perceived distance of the cube varies appropriately as the perceived location of contact between the platform and the ground varies; (2) variability increases systematically as the relating surfaces move apart; and (3) certain local edge alignments allow precise propagation of distance information. These results demonstrate considerable efficiency in the mediation of distance perception through nested contact relations among surfaces.

Distance Perception↗
PubMed1996

Gravitational acceleration as a cue for absolute size and distance?

When an object's motion is influenced by gravity, as in the rise and fall of a thrown ball, the vertical component of acceleration is roughly constant at 9.8 m/sec2. In principle, an observer could use this information to estimate the absolute size and distance of the object (Saxberg, 1987a; Watson, Banks, von Hofsten, & Royden, 1992). In five experiments, we examined people's ability to utilize the size and distance information provided by gravitational acceleration. Observers viewed computer simulations of an object rising and falling on a trajectory aligned with the gravitational vector. The simulated objects were balls of different diameters presented across a wide range of simulated distances. Observers were asked to identify the ball that was presented and to estimate its distance. The results showed that observers were much more sensitive to average velocity than to the gravitational acceleration pattern. Likewise, verticality of the motion and visibility of the trajectory's apex had negligible effects on the accuracy of size and distance judgments.

Acceleration↗
PubMed1989

The roles of convergence and apparent distance in depth constancy with motion parallax.

The question of whether motion parallax is calibrated by convergence or by apparent distance for depth perception was addressed in three experiments. In Experiment 1, a random dot parallactic display was viewed monocularly at a distance of 80 cm, and the convergence angles were set for distances of 40, 60, and 80 cm. Averaged apparent depth was not different across conditions. In Experiment 2, a display consisting of one surface showing dollar bills and one surface showing random dots was viewed monocularly at a distance of 80 cm. It was presented at two different apparent distances, which were manipulated by varying the size of the dollar bills. In one condition, normally sized dollar bills were presented, and in another condition, the size was reduced by 30%. The averaged apparent depth associated with the small-bill display was larger than the depth associated with the normally sized bill display. In Experiment 3, a random dot display was viewed monocularly at 120 cm. In the primary condition, the random dot display was viewed with an induction screen at 80 cm, and it was moved from side to side such that it appeared stationary and close to the plane of the induction screen. In a comparison condition, the display was viewed without the induction screen and was moving from side to side at 120 cm. In another comparison condition, the display was again viewed without the induction screen but was stationary at 120 cm. Observers adjusted the extent of motion parallax so that apparent depth was 1 cm. The mean extent of parallax was larger in the primary conditio.(ABSTRACT TRUNCATED AT 250 WORDS)

Accommodation, Ocular↗
PubMed1990

Relative distance judgments of familiar and unfamiliar objects viewed under representatively natural conditions.

Carlson and Tassone (1971) reported that an object of familiar size viewed at an appreciable distance is perceived to be more distant than an unfamiliar object. Six experiments were designed to examine this effect. The results indicated that the effect is not dependent on Carlson and Tassone's method for assessing perceived relative distance; it occurs at some minimum viewing distance; it is unlikely to be caused by stimulus attributes confounded with the familiar versus unfamiliar size dichotomy; appears to be specific to judgments of the familiar object itself; and it does not occur if the familiar and unfamiliar objects have a common reference target. These findings are discussed with respect to the issue of whether familiar size influences perceived distance as distinct from influencing judgments of distance.

Adult↗
PubMed1992

The role of instructions and familiar size in absolute judgments of size and distance.

The effects of familiar size and instructions (apparent, objective) on direct reports of size and distance were evaluated. Subjects estimated the size and distance of two different-sized playing cards or two unfamiliar stimuli under either apparent or objective instructions. The stimuli were presented successively at a distance of 5.48 m under reduced-cue conditions. The form of the instructions selectively influenced the effect of familiar size on absolute judgments of size and distance, with apparent instructions minimizing, and objective instructions promoting, familiar-size effects. The ratio of the distance judgments of the first to the second presented stimuli approximated the relative retinal sizes of the two objects under both apparent and objective instructions, while the ratio of size judgments tended to be either influenced by or independent of the object's relative retinal sizes under apparent and objective instructions, respectively. These results are consistent with Gogel's theory of off-size perception and, in particular, with the claim that, in comparison with apparent instructions, objective instructions are more likely to direct observers to base their judgments on cognitive, as opposed to perceptual, sources of spatial information.

Adult↗