1986 l

Visualizing Spatial Tasks: A Comparison of Computer Graphic and Full-Band Video Displays Stephen R. Acker Elisa L. Klein

Stephen R. Acker is an assistant professor, Depart- ment of Communication, and Elisa L. Klein is an associate professor, Early and Middle Childhood Edu- cation, The Ohio State University, Columbus, OH 43210.

Three spatial tasks were created in two forms, as video and as computer graphics. Both forms o~ each task were presented to third graders, middle schoolers, and university students. Middle schoolers and adults preferred working with the video but were more accurate working with computer graphics. Third graders preferred the computer but were equally successful working with both displays. The study suggests that the expectations with which students approach an inst~cfional technology may determine the effectiveness of that technology more than characteristics of the technology in question.

ECTJ, VOL. 34, NO. 1, PAGES 21-30 ISSN 0148-5806

Computers are becoming a major instructional tool in the classroom, taking their place alongside videotape and other educational technologies. Given the limited budget of most schools, expensive computer systems may replace--rather than supplement--equal ly expensive video equipment and programming. This shift is occurring without much understanding of the differences between learning in the two technological settings.

This study examines one major difference between videotape and computer graphics: the level of realism inherent in their display systems. Since each presents visual information at a different level of abstraction, students of different ages may differ in their ability to make use of the visual displays. Specifically, the purpose of this study was to compare the ability of third graders, middle schoolers, and university students to estimate end states of visual transformations from video and computer graphic ver- sions of spatial tasks. Their preference for working with videotaped or computer- generated materials was also considered.

Learning from Different Media

Schramm's (1977) summary finding that both classroom instructors and video are capable of conveying information extends to the debate between computer graphics and video: Both work. Clark (1983) concurs

22 ECTJ SPRING1986

and observes that many studies reporting the superiority of any particular media ve- hicle may "reflect artifact or editoral bias favoring new media" (p. 446). Consistent with these cautions, this study does not offer a global comparison between video and computer graphics nor does it suggest that either may be superior to traditional methods of presenting information. In- stead, the starting point for this work is simply that too little is known about how the display characteristics of the computer influence learning.

There is substantial literature on the relationship between characteristics of a mediated image and the viewer's interpre- tation of the visual information presented in the image. One contributor is Winn (1980) who argues that the role of visual imagery depends on how the learner expects to use the information presented and that "recall and manipulation tasks, depending heavily on the realistic representation of the elements (emphasis added) in a picture and of the patterns among them, tend to cause visual information to be coded as images" (p. 130).

Characteristics of the visual display are important in the imagery processes used for encoding the information. For example, Paivio (1975) reports that subjects were slower in selecting whether a donkey or toaster is larger in real life when the comparison was made between a large picture of a toaster and a small picture of a donkey. When the word "toaster" was presented in large type size and the word "donkey" was presented in small type size, subjects more quickly identified the correct comparison. In a later publication, Paivio (1978) con- cludes: "Visual memory knowledge seems to be truly analogous to the information de- rived directly from visual perception, at least in regard to object size" (p. 120).

To the extent that display characteristics influence visual perception and memory for visual/spatial information and to the extent the display differs from or conforms to a "realistic representation," differences in videotaped and computer generated displays may be important. On videotape, the visual image is concrete, rich in detail, and dearly presents "real" events, in contrast, the computer presents an abstract image of less detail that only represents a real event.

These differences are accentuated in commonly available educational computer software because the current protocols through which microcomputer animation is created inherently limit the resolution and complexity of animated computer sequences. For example, in the popular language SuperPILOT, animation sequences allow the animator to redefine the standard ASCII character set with shapes of his/her own design. Each ASCII character takes up seven screen spaces. So, in the horizontal dimension, there are only 40.(280/7) discrete animation points. This limits the precision of SuperPILOT, and most other, animated displays. As a result, movements are not particularly fluid, pixel definition is coarse (i.e., the images are "blocky"), and few programming efforts have successfully created rich visual scenes or context for foreground events.

These differences between computer and videotape display characteristics may be particularly important in presenting instructional materials in visually oriented subjects. For example, much information in mathematics is visual and relies on sketches, diagrams, and other visual support materials. Further, spatial abilities and mathematical abilities have been shown to be positively correlated (Eastman & Carey, 1975; Guay & McDaniel, 1977; Moses, 1979). In a related area, Lowney and Knirk (1982- 1983) argue that interaction with microcomputer games may improve spatial and mathematical skills. Papert (1980) concurs and has developed an entire approach to learning certain mathematical skills based on "turtle graphics," using LOGO, a programming language designed to help students discover principles of geometry. In addition to mathematics, geography, art, and the natural sciences present much of their content visually (Shepard, 1978).

Since video material can capture detailed contextual clues and computer graphics rely on more abstract representations, there may be age-related differences in learning from video and computer graphic displays that rely Heavily on visual elements. Piaget's stage theory of cognitive development (Piaget & Inhelder, 1956, 1971) suggests that thought processes emerge in an invariant order. During the concrete opera-

VISUAUZING SPATIAL TASKS 23

tional stage, the context of a problem and the perceptual information that exists in that context are particularly salient (Beard, 1969; Piaget & Inhelder, 1956). Adult, for- mal operational thought relies more on abstracted, generalized principles and is less context bound (FlaveU, 1977; Piaget & Inhelder, 1971).

Numerous studies (Liben, 1981; Liben, Patterson, & Newcombe, 1981; McGee, 1979; Piaget & Inhelder, 1956; Piaget, In- helder, & Szeminska, 1960) have supported the relationship between cognitive development and spatial abilities. Piaget and Inhelder (1971) proposed that children's spatial abilities arise out of the construction of a Euclidean coordinate reference system. The development of such a system is related to logical reasoning, and older children are generally more successful at spatial tasks than younger children.

Besides age, perhaps the most significant differences in spatial abilities have been related to gender. In studies across a wide variety of spatial tasks, males perform con- sistently better than females (see Harris, 1981 and McGee, 1979, for an extensive review of the research). On tasks assessing horizontality and verticality, females perform more poorly regardless of attempts to remove "physical" aspects of the task that might tap possible differences in knowledge about the physical world (Liben & Golbeck, 1980).

Various explanatory mechanisms have been suggested for this differential performance. While genetic, hormonal or later- ality hypotheses have been proposed (e.g., Buffery & Gray, 1972; McGee, 1979), the impact of socialization differences for boys and girls (for example, differences in ma- nipulative toys, freedom to explore the environment, discouragement from taking mathematics or engineering courses) have been strongly implicated (e.g., Fennema, 1977; Moore & Young, 1978; Newcombe & Bandura, 1983; Sherman, 1977).

Since education in visually oriented subject matter is likely to increasingly rely on computer and/or video technologies, an analysis of their value for students of different ages and gender may be useful. This study examines the following specific hypotheses.

Hypotheses

1. When asked to perform visual transformation tasks, third-grade subjects will perform better when the tasks are presented on videotape compared to when the tasks are presented as computer graphics.

2. Third-grade subjects will prefer performing visual transformation tasks when the tasks are presented on videotape a s compared to when the tasks are presented as computer graphics.

3. Middle-school/high-school and adult subjects will perform better on v~sual transformation tasks presented as computer graphics than on equivalent tasks presented on videotape.

4. Middle-school/high-school and adult subjects will prefer performing visual transformation tasks presented as computer graphics than when equivalent tasks are presented on videotape.

5. Middle-school/high-school and adult subjects will more accurately perform visual transformation tasks than will third graders, independent of the display medium.

6. At each grade level, males will offer more accurate solutions to visual transformation tasks than will females.

METHOD

Subjects

A total of 98 subjects participated in this study. Thirty third graders (M~e = 102 months, SD = 6.8) were drawn from a mid- die-income parochial school and 36 mid- die-school/high-school students (Mo~ = 170 months, SD = 15.8) participated as an activity of a summer computer camp. Thirty-two students from a large midwest- em university (Maa, = 272 months, SD = 37.3) were also included in the sample.

Experimental Materials

Three 30-second spatial transformation tasks were produced as color video programming on u V, HS equipment. Camera/deck resolution was better than 300 lines at center. For each segment the 12-72 zoom lens was set at 25mm, "normal" for a ~/3" camera tube. Motion was always per- pendicular to the lens axis, so perspective did not confound distance judgments,

24 ECTJ SP~NGI986

The three visual problems were presented in sto W form and based on transformations Piaget developed to study mental imagery. The first problem involved estimating where the end of a vertical line pivoting about its base will fall if "pushed over" so it lands in the horizontal plane. This transformation problem was represented as a carpenter driving nails with a hammer on a roof. The carpenter's right elbow rested on the roof and the hammer was held vertically in the carpenter's right hand. His left hand moved a nail along the roof line searching for the spot where the hammer would strike the nail. The carpenter moved the nail from just in front of his body to arm's length. Subjects were asked to "freeze" the carpenter's left hand at the point where the nail should be placed so the hammer head would hit the nail.

The second task was to estimate the straight-line length of a semicircle. This task was put into a storyline of a person hanging a clothesline. The subject saw a person holding a slack clothesline, one end of which was attached to a tree. The subject was asked to locate a pole so that the clothesline would hang perfectly straight when stretched out and attached to the pole.

The third task involved estimating the straight-line length of two sides of an isos- celes triangle. This transformation was presented as a cheerleader moving from a standing position into the splits. Subjects were asked to estimate where the cheerleader's right foot would be after she had accomplished a full splits. The three tasks are represented in Figure 1.

From these three videotape segments, three computer graphic analogs were created using SuperPILOT, a Pascal-based language that runs on Apple computers. SuperPILOT uses Apple's high-resolution graphic screens, which offer a resolution of 280 (horizontal) x 192 (vel;tical) screen dots (SuperPILOT Language Reference Manual, 1982, p. 122). This resolution is comparable to that of the video system used. Animation sequences from within SuperPILOT's character set editor allow for simulations of motion. In each of the three graphic representations, the relative screen sizes of the images were within 10% of the image sizes

presented in the original full-motion video sequences.

Procedures Subjects were tested individually. First, one experimenter explained the study as a learning experiment in which the student would be asked to solve video and computer problems. Sex, age, and grade were recorded, and then subjects moved to. the experimental station.

At the experimental station, two matched 25-inch color JVC monitors were set up with one attached to a Panasonic 8950 dual-field VCR and the other to an Apple IIe. The Panasonic, which displays "tear-free" still frames and presents both video fields si- multaneouly for better resolution and brightness, provided an image equal in clar- ity to the graphic disphy. The order in which the video and graphics were presented was counterbalanced across subjects. Similarly, the order in which tasks were presented was balanced within the video and computer conditions.

In both the video and computer tasks, the storyline was established first. Then one of the three transformations was presented. For example, a subject Would see "Bob-Tom the carpenter" and watch him swing the hammer he was holding through 15 degrees of arc three times. This short swing was introduced to help the subject estimate where to place the nail so that the carpenter's full 90-degree swing would hit the nail. After the practice swings were shown, the hammer returned to vertical. Text on the computer screen, which was read aloud by the experimenter, instructed the subject to place the nail where it would be hit by the hammer. The nail was moved on the screen by using a game paddle. When the subject was confident of his/her estimate, the screen location was entered into the computer's register. Then the hammer again moved through the 15-degree arc, and the subject was asked whether the guess was "OK" or should be changed. For each task, this feedback mechanism was built in so a subject always had the opportunity to refine his/her estimate. Only after the subject was satisfied with his/her estimate, did the transformation actually occur (the hammer fell through the 90-degree arc) so the subject

VISUALIZING SPATIAL TASKS 25

FIGURE 1 Spatial tasks embedded in real-life contexts

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26 ECTJ SPRING~986

could observe his/her relative success. A program subroutine calculated the percent- age and absolute error of the subject's re- sponse by subtracting the estimated distance from the actual distance and dividing by the actual distance.

While the videotape procedures were similar, they weren't as automated. The experimenter orally presented the storyline and '~stepped through" the video in slow motion forward or reverse to give the student feedback. Estimates were "entered" by using a felt-tipped marker on the screen and erased with an alcohol swab for "'re- entry." Measurements were made with a tape measure calibrated in millimeters and recorded using paper and pencil.

After responding to the video and computer problems, subjects were asked to imagine that their teacher was going to miss a week of class and that the "substitute teacher" would be individualized instruction delivered with either a computer and a set of disks or a VCR with a set of vid- eotapes. The class topic was given as "math-like material like we've seen here."

Based on this scenario, students were asked to say which teaching system they would prefer to use for learning and from which system they would find it easier to learn. Both responses and the reasons for the responses were recorded. Then the subject's questions were answered and they were thanked and debriefed.

Analysis A 2 (gender) x 3 (grade) x 2 (mode) x 3 (task) ANOVA with repeated measures on mode (computer , video) and task (clothesline, hammer , cheerleader) was used to examine factors related to the accuracy of subjects' estimates from the computer and video displays. A chi-square test of independence was used to examine whether subjects at different grade levels thought computer graphics or full-motion video more clearly presented spatial infor- maEon and which medium provided a more enjoyable learning experience.

RESULTS

The a priori hypotheses about subject accuracy involved the interaction of grade level

with presentation mode and the main effects of grade and sex. Third graders were predicted to perform relatively better on video than on computer, while middle schoolers, and university students were predicted to perform better on the computer graphics version of the task. Older subjects were expected to perform more accurately than younger subjects, and males were expected to more accurately assess the tasks than were females.

The results of the analysis of variance showed no statistically significant differences in the accuracy of task performance at the different grade levels (F [2,92J = .67; p > .05) or between males and females (F [1,92] = 1.55; p > .05). Nor did accuracy of task performance differ across the different tasks (F [2,184] = .46; p > .05). However, the main effect of mode was statistically significant (F [1,92] = 9.17; p < .05); subjects were more accurate on the computer version of the tasks than on the video version of the tasks.

Among the two-way interactions, the modexgrade (F [2,92] = 3.1; p < .05), modextask (F [2,184] = 15.8; p < .05), and taskxgroup (F [4,184] = 7.6; p < .05) effects were statistically significant. Neither the three-way interactions nor the four-way interaction were statistically significant.

The Newman-Keuls multiple comparison test was used to determine which of the cell means differed at a statistically significant level in the event a statistically significant F-ratio had been obtained. When consider- ing the mode x group interaction, both middle schoolers and adults more accurately judged computer displays than video displays. These results, which present data relevant to hypotheses one and three, are presented in Figure 2. When the means of the different mode x task cells were compared, subjects were more accurate on the computer version of the cheerleader and clothesline tasks. The final set of comparisons involved the interaction between task and group. In this case, third graders were more accurate on the cheerleader task than on the cloth6sline task.

The results of the chi-square test of independence support the conclusion that third graders generally preferred and thought they could learn more from the computer,

VISUALIZING SPATIAL TASKS 27

FIGURE 2 Error on Video and Computer Tasks for Different Grades

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14

10

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COMPUTER

Third Middle School University

Grade Level

while adults expressed the opposite belief. The opinions of middle schoolers were more evenly split, although video was more often preferred and more often considered better at displaying information. These re- suits are supported at the alpha < .05 level and presented in Tables I and 2.

DISCUSSION Although middle schoolers and adults preferred video, they were more successful working from computer displays. Third graders generally preferred the computer even though they were no more accurate on the computer or video display.

These results could be a variant of Clark's (1982) finding that there are negative corre- lations between student achievement and their enjoyment of instructional methods under certain circumstances. His argument is based in part on the premise that students are poor judges of the amount of effort they must expend to maximize learning but that a challenge must be presented in the in-

TABLE 1 Media Preferred as a Source of Learning Materials at Different Grades.

Third Middle School/ Grade High School University

Prefers video 5 25 23

Prefers computer 25 11 9

Note. x2(2; N = 98) = 21.7; p < .05.

TABLE 2 Media Judged Better for Conveying Information at Different Grades

Third Middle School/ Grade High School University

Video better 8 21 20

Computer better 22 15 12

Note. x:(2; N < 98) = 8.2; p < .05.

28 ECTJ SPRING J986

structional sett~g for learning to occur. In this study, the university students found the computer "less friendly," "more demanding," and "less human" than the video. Even though they were attending computer camp, middle schoolers shared this attitude toward the computer. Many of these teenagers felt they had to learn computer technology to prepare for a future career; they did not express a specific enthusiasm or desire to know about computers.

In contrast, the third graders found the computer more "engaging" and "interac- t ive." They approached the computer graphics as a medium over which they had control. Even though the video was also interactive and under the child's control, this control was exercised by instructing an adult to back up or forward the progression of video images. This social interaction may have interfered with the child's absorption in the task and appreciation for the video.

With the university population, society's first "TV generation," the newness of the computer may have made them ~nore un- comfortable but more engaged in the task at hand. Similarly the middle schoolers, even those 12 years old, discussed the computer as a tool that had to be mastered for future employment in society. These groups may have viewed television as an entertainment medium, not as an instructional technology that demanded effort and involvement.

One characteristic of the tasks deserves further scrutiny: the possibility that different levels of human interaction might have influenced the results. As mentioned, estimates were changed "automatically" on the computer through the use of a game paddle while changes in estimates made on the video required the researcher to wipe off a mark on the monitor and the subject to re- mark the screen. Although both forms of feedback required the experimenter to ex- plain the feedback procedures in words, the subjects had to request that the adult do something (erase the mark) in the video condition. To the extent that younger children feel intimidated by directing an adult, third graders may have felt somewhat in- hibited in refining their video estimates. Consequently, these results may underrep- resent the younger subjects' accuracy on the

video presentation. Although the exper- imenters certainly tried to put all subjects at ease, procedures to make the social interaction patterns more comparable (e.g., the experimenter might manipulate the game paddle as instructed by the subject) might be preferable.

The age and sex differences commonly found in performance on spatial tasks were not found in this study. Maybe this is partly a result of earlier and more uniform expo- sure to mathematical/spatial topics in the schools. Another possible, explanation is that most past research on age and gender differences has assessed performance on static spatial displays and not on imagery tasks that incorporate motion. As Gibson (1966, 1979) details, motion conveys a great deal of visual information about spatial rela- tionships, and this may be attenuating age and gender differences that have been re- ported based on static stimuli. A study in which static and kinetic spatial abilities are assessed at the same time may help clarify the issues surrounding age and gender differences.

Overall, the cheerleader and clothesline tasks were more accurately estimated on the basis of the computer display. The contri- butions to this difference were greatest from the university and middle-school segments of the sample. Most likely, the underlying reason for this result is the same as that advanced for the mode by group interaction. Older students felt more challenged by the computer, applied themselves more, and consequently performed better.

The task by group interaction appears to reflect mainly the very accurate estimates by third graders on the cheerleader task and the relative difficulty they had with the clothesline task. This may be a result of the difference in feedback between the cheerleader and clothesline tasks. In the cheerleader task, the cheerleader first "stretched." This feedback, which traced the early stages of the splits, may have helped the subjects visualize the full-splits end state. The feedback provided in the clothesline ~ask was movement of the pole (endpoint) to the subject's selected spot. Since the clothesline did not begin the transformation from arc to straight line until the subject had finalized his/her estimate,

VISUAUZ1NG ,SPATIAL TASXS 29

the "previsualization" afforded in the cheeleader task was not available in the clothesline task.

CONCLUSION Three spatial tasks were created as computer graphic and full-band video to examine whether accuracy of judgments from different kinds of visual displays was related to the subject's age or gender. In this experiment, middle schoolers and adults were more accurate when estimating from computer graphic displays. Third graders exhib- ited the same degree of accuracy independent of the display medium. There were no gender-related differences, perhaps because the socialization of boys and girls is becoming more uniform with respect to spatial/mathematical concepts and perhaps because the judgment tasks included motion, a spatial cue powerful enough to mask weak gender effects.

University students overwhelmingly preferred video as a source of instructional material, while third graders were equally favorably impressed by the computer. Mid- dle schoolers more often preferred video, although preferences were more evenly split in this group.

In spite of the preferences expressed, university and middle-school students were more accurate when judging from computer displays than from video. This may reflect an orientation to the media rather than any characteristics of the media per se. These students generally thought computers were more "demanding," while video was a "friendlier, more entertaining" medium. This preconception may have led to higher involvement with the "instructional" computer and less engagement with the "entertainment" medium of television.

Although this study was premised on differences in the strengths of display media--the capacity for detail of the video and the tendency for computer graphics to be more abstract--results of this study suggest that the methods through which students are introduced to "new" instructional technologies may outweigh differences in the characteristics of the media under con- sideration.

There are several implications for education that can be drawn from this study. First, older students were found to use more effectively abstracted rather than full-detail visual information. This suggests that media productions targeted for older students, whether for video or computer, should avoid superfluous detail included in the name of realism. In visually based subjects, as well as verbally based subjects, instructional design concepts, rather than display capabilities of competing media, are likely to be more strongly related to learning. A focus on design is supported by the trend toward a merger of video and computer technologies. For example, videodisc re- leases can integrate full-band video and computer graphics as dictated by the instructional design.

The importance of the particular technology chosen to deliver instructional programming may be more dependent on the expectations learners bring to the educational setting based on their previous, out- of-school experiences with the technology. As more students experience computers at home, in arcades, or in other nonschool en- vironments, their expectations about computers may change to parallel their expectations of television, a medium principally used for entertainment.

The instructional design community may need to develop presentation protocols that clearly signal that a program is educational and demands the learner's involvement. Both video and the computer are flexible tools that can entertain, foster escapism, or promote learning. The research challenge is to develop display techniques, not technologies. These techniques should es- tablish a cognitive set toward learning when the intended outcome of the application of technology is education.

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