Evidence for Conjoint Retention of Information ... - Science Direct

CONTEMPORARY EDUCATIONAL PSYCHOLOGY ARTICLE NO.

21, 221–239 (1996)

0020

Evidence for Conjoint Retention of Information Encoded from Spatial Adjunct Displays DANIEL H. ROBINSON, ANDREW D. KATAYAMA,

AND

AI-CHUN FAN

Department of Counselor Education/Educational Psychology, Mississippi State University Two experiments were conducted to determine whether the conjoint retention hypothesis (Kulhavy, Lee, & Caterino, 1985) is a viable explanation for the facilitative advantages of adjunct displays by examining whether encoding and retrieval processes involve using the visuospatial sketchpad component of working memory (Baddeley, 1992). Experiment 1 investigated encoding effects on working memory performance by having college students view (a) a verbal or spatial representation, (b) an adjunct display, and then be tested on (c) recognition of the representation, and (d) comprehension of the adjunct display. In Experiment 2, (a) and (b), and (c) and (d) were reversed to examine retrieval effects. Results indicated that spatial memory was worse than verbal memory when processing graphic organizers, concept maps, and outlines, but not text; and when retrieving information after processing graphic organizers and concept maps, but not outlines and text. Thus, the conjoint retention hypothesis explains the facilitative advantages of spatial, but not linear adjunct displays. q 1996 Academic Press, Inc.

There is overwhelming evidence that when text is accompanied by adjunct displays [e.g., displays that appear outside the main body of text such as pictures (Levie, 1987), geographic maps (Kulhavy, Stock, Peterson, Pridemore, & Klein, 1992), diagrams (Winn, 1991), graphs (Behrens, Mulvenon, Robinson, White, & Stock, 1990), concept maps (Lambiotte, Dansereau, Cross, & Reynolds, 1989), graphic organizers (Robinson & Kiewra, 1995), advance organizers (Corkill, 1992), or outlines (Darch & Gersten, 1986)], comprehension of text information represented in the displays is facilitated. Most researchers agree that this ‘‘adjunct display effect’’ (ADE) demonstrates that these displays are potentially effective and should accompany text when possible. Researchers disagree, however, regarding the issue of why the ADE occurs. Levin and Mayer (1992), for example, have recently identified seven different explanations! Among the more interesting explanations for the ADE is one that focuses on the possibility that information contained in adjunct displays is processed differently than information contained in text. The conjoint retention (CR) hypothesis (Kulhavy, Lee, & Caterino, 1985) states that text information referenced in an adjunct display is encoded in memory both verbally and spatially, whereas text information that is not referenced in an adjunct display

Address correspondence and reprint requests to Daniel H. Robinson, P.O. Box 9727, Mississippi State, MS 39762. E-mail: [email protected]. 221 0361-476X/96 $18.00 Copyright q 1996 by Academic Press, Inc. All rights of reproduction in any form reserved.

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

222

ROBINSON, KATAYAMA, AND FAN

is encoded only in verbal format. Thus, information that is encoded conjointly is more likely to be retrieved because the spatial representation provides an additional node that may be activated after an initial attempt to retrieve the verbal representation fails. For this reason, the spatial features of an adjunct display are thought to serve as a ‘‘second stratum cue’’ (Kulhavy et al., 1992) that steps up to substitute for the inadequate verbal representation. The CR hypothesis is basically an extension of dual coding theory (Paivio, 1986) which contrasts concrete vs abstract information. CR, however, contrasts only verbal vs spatial information. Although the CR hypothesis was developed by investigating geographic maps, recently Kulhavy et al. (1992) proposed that CR may also explain the ADE when using other types of adjunct displays. In the present study, we tested this proposal by investigating whether studying less spatial and/or pictorial adjunct displays involves encoding spatial information. If we found that spatial information was encoded from other adjunct displays besides geographic maps, then the claim made by Kulhavy et al. (1992) would be supported. If we found that spatial information was encoded from some types of adjunct displays but not others, then we could conclude that the CR hypothesis may explain the ADE for some, but not all, types of adjunct displays. At best, our encoding evidence would only support one necessary assumption of the CR hypothesis—spatial encoding of the adjunct display. It would not provide sufficient evidence supporting the entire CR hypothesis. We felt that because adjunct displays may differ in both the amount of pictorial features (i.e., geographic maps contain drawings and/or icons whereas graphic organizers contain only words) and the amount of spatial features (i.e., graphic organizers use rows and columns whereas outlines use only rows), explanations as to why the ADE occurs for each type of adjunct display may also differ. On the other hand, if only one explanation for the ADE can account for all types of adjunct displays [as suggested by Kulhavy et al. (1992)], then at least it must be shown that the same processes are used when comprehending different adjunct displays. A recent study by Kruley, Sciama, and Glenberg (1994) has provided the methodology needed to test these competing hypotheses. They investigated whether studying text accompanied by pictures makes use of the visuospatial component of working memory (Baddeley, 1992). They found that when students attempted to comprehend texts that were accompanied with pictures as compared to texts that have no pictures, students’ performance on a spatial working memory task was diminished. Kruley et al. (1994) concluded that viewing a picture encouraged the building of a spatial mental model through use of the visuospatial sketchpad, using up limited working memory needed to perform the spatial working memory task, and thus inhibiting students’ recall. The sketchpad is one of two slave systems (the other is the phonological loop) that, along with the central executive, make up working memory (Gathercole & Baddeley, 1993). Whereas the phonological loop is specialized for the processing and storage of verbal information, the sketchpad is used mainly

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

SPATIAL ADJUNCT DISPLAYS

223

for visual and spatial information. Gathercole and Baddeley (1993) have stated that ‘‘unsurprisingly, there is little evidence that . . . (the sketchpad) . . . plays a significant role in language’’ (p. 17). Because learning from text would indeed appear to play an important role in the language development of students, the findings of Kruley et al. (1994) suggest that the sketchpad may perhaps be an untapped resource for use in text comprehension, and provide evidence supporting the CR hypothesis as a viable explanation for the ADE. The present study tests the claim made by Kulhavy et al. (1992) that the CR hypothesis may explain the ADE by investigating the role of the sketchpad when students study other adjunct displays besides pictures. The type of adjunct display we first chose to investigate was the graphic organizer. A graphic organizer, by definition, is a ‘‘diagrammatic representation of the basic vocabulary of a unit so as to show relations among the concepts represented by those words’’ (Herber & Sanders, 1969, p. 4). Robinson and his colleagues (e.g., Robinson & Schraw, 1994; Robinson & Kiewra, 1995) have recently found advantages for graphic organizers as adjunct displays when students are required to learn concept relations, express those relations in an integrated writing style, and apply knowledge in new situations. Graphic organizers, although being more spatial than text, are also different from both pictures and geographic maps in the sense that they contain only verbal, rather than pictorial features. Very simply, we wanted to investigate whether text accompanied with graphic organizers involves visuospatial processing in the same way as text accompanied with pictures. Following the lead of Kruley et al. (1994), our rationale was that if graphic organizers are processed using the visuospatial sketchpad more than the phonological loop, then viewing a graphic organizers while listening to text should interfere with a spatial, but not verbal, working memory task. This would mean that although graphic organizers contain only verbal stimuli, the majority of working memory space is being used to process the spatial relations among those stimuli. Viewing text, on the other hand, should not interfere with a spatial task more than it would with a verbal task because text is not processed using the sketchpad more than the loop. Our methodology was similar to that used by Kruley et al. (1994), who used concurrent tasks based on the premise that ‘‘having found ways of separately disrupting spatial and verbal processing, one can explore the relative contribution of different subsystems to complex tasks’’ (Baddeley, 1992, p. 558). EXPERIMENT 1a

Experiment 1a was designed to provide evidence that processing graphic organizers involves use of the visuospatial sketchpad which, in turn, would be consistent with the claim that the CR hypothesis may explain the ADE for other adjunct displays besides geographic maps (Kulhavy et al. 1992). We used two grouping conditions: a verbal condition where a digit sequence was presented, and a spatial condition where a dot configuration was presented. Research sug-

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

224


gests that persons use the loop to process digit sequences verbally (Baddeley & Hitch, 1974) and the sketchpad to process dot configurations (similar to chess positions) spatially (Baddeley, 1992). In both conditions, after students saw the initial representation they viewed an adjunct display (either a text or a graphic organizer) while listening to someone orally read a text. We defined text here as an adjunct display here simply because students would be viewing it as an adjunct while listening to the text being read. During this activity, the students were attempting to perform two tasks concurrently—remember the initial representation and comprehend the text. Students were then presented with two digit sequences or dot configurations, depending on the grouping condition, and asked to choose the one they had previously seen. This was followed by a text comprehension test, containing fact and comparison items. We hypothesized that the presence of a graphic organizer would encourage the construction of a spatial mental model which would compete for the limited resources of the sketchpad with the internal representation of the dot configuration. This would become apparent if students’ performance on the spatial memory task was worse than their performance on the verbal memory task when they viewed graphic organizers, but not when they viewed text. In addition, the spatial memory task could also inhibit the ADE of the graphic organizer by interfering with performance on the comprehension test. Either of these two scenarios would provide evidence that graphic organizers are processed using the visuospatial sketchpad. Because the materials we constructed dealt with concrete objects such as animals (e.g., sharks, buffalo, marsupials, etc.), we did not expect to find evidence confirming previous findings that text is processed in a way that involves using the phonological loop more than the sketchpad. Instead, we felt that listening to the text would likely cause students to activate images of the animals (especially when describing their color and other features) and they would process that information using both the loop and the sketchpad. This would have the effect of making a stronger argument for spatial processing of graphic organizers if either of the previous scenarios were observed because the sketchpad would be used for processing demands above and beyond simple activations of concrete images. Method

Design and Subjects Memory task was a between-subjects variable, whereas adjunct display was a within-subjects variable. The base design was a 2 memory task (verbal vs spatial) 1 2 adjunct display (text vs graphic organizer) mixed-model. The subjects were 68 student volunteers attending a large public university in the South, with about an equal number of males and females in the sample. Students were randomly assigned to between-subjects conditions. Cell sizes are presented in Tables 1 and 2.

Materials All materials except the answer sheets were prepared on 8.5 by 11 in. overhead transparencies. The answer sheets consisted of 8.5 by 11 in. sheets of plain white paper numbered 1 through 50.

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP


225

FIG. 1. Example of a verbal memory representation and test.

Memory representations. Twenty memory representations were constructed: ten verbal and ten spatial. Each verbal representation consisted of four different digits, presented on the same line, left to right. The spatial representations were constructed to be similar to those used in the third experiment of Kruley et al. (1994), corresponding to Difficulty Level 6. Each spatial representation consisted of a rectangular grid, 9 cells by 9 cells, and five round filled (solid black) dots, each contained within a cell of the grid. Memory tests. Twenty memory tests were constructed: 10 verbal and 10 spatial. Each verbal test consisted of two sets of four different digits presented on the same line separated by 2 in., with the letters ‘‘A’’ and ‘‘B’’ directly above each. One of the sets was the same as its corresponding memory representation; the other differed by reversing the positions of either the first and third digits, or the second and fourth digits. An example of a verbal memory representation and test is shown in Fig. 1. Each spatial test consisted of two grid-and-dot configurations presented on the same horizontal separated by 2 in., with the letters ‘‘A’’ and ‘‘B’’ directly above each. One of the test configurations was the same as the memory representation (except that the entire pattern was displaced); the other differed by displacing two of the dots a distance of one cell (above, below, left, right, or diagonally). An example of a spatial memory representation and test is shown in Fig. 2. Adjunct displays. Ten short texts were written (number of words ranged from 130 to 209), each describing three coordinate concepts and their corresponding attributes. Coordinate concepts belong to the same larger class but have different attributes (Eggen & Kauchak, 1994). For example, the Sand, Mako, and Thresher sharks are coordinate concepts because all of them are sharks but differ in terms of diet, length, etc. Five graphic organizers were constructed from five texts that were randomly chosen from the ten. An example of one of the texts is displayed in Fig. 3. An example of one of the graphic organizers, constructed from the text in Fig. 3, is displayed in Fig. 4. Comprehension tests. Ten comprehension tests were written, each containing four multiplechoice items. On each test, the first two items measured knowledge of concept facts and the last two measured knowledge of concept comparisons. Fact items required the student to identify which concept possessed a certain attribute. Comparison items required the student to correctly identify which concept possessed a comparative relationship along a certain attribute category with the other two concepts. An example of one of the comprehension tests is listed below. 1. Which shark is found in all warm waters? a. Sand

b. Mako

c. Thresher

2. Which shark swims alone? a. Sand

b. Mako

c. Thresher

3. Which shark weighs the most? a. Sand

b. Mako

c. Thresher

4. Which shark is the longest in length? a. Sand

ab01$$0903

05-21-96 08:52:42

b. Mako

cepal

c. Thresher

AP: CEP

226


FIG. 2. Example of a spatial memory representation and test.

Procedure Groups of about 20 students were seated in a classroom where they could easily see the overhead screen. The experimenter explained the purpose of the study and distributed answer sheets. Students were told that they would be attempting to do two things at once and that they

FIG. 3. Text.

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP


227

FIG. 4. Graphic organizer.

should try to do their best at both tasks. The following sequence of events was repeated ten times for the two memory task groups (the first two sequences were used as practice with corrective feedback provided upon completion; thus, only data from eight sequences were analyzed). First, the memory representation was shown on the screen for about 5 s. Then the representation was removed and the adjunct display (in alternating order) was shown while the experimenter orally read the corresponding text at a rate of approximately 160 wpm. When the experimenter finished reading the text, the adjunct display was removed and the memory test was presented for about 5 s. Students were instructed to mark on their answer sheets ‘‘A’’ or ‘‘B’’ to indicate which of the two choices was the same as the one they had previously seen. Then the memory test was removed and the comprehension test was shown for about 40 s. The students were instructed to mark on their answer sheets ‘‘A,’’ ‘‘B,’’ or ‘‘C’’ to indicate the correct choice. Each student participated for about 30 min.

Analysis For all experiments, the following analyses were performed on the raw scores. We did not choose to use a 2 memory task X 2 adjunct display factorial analysis of variance for the memory test scores because we included four different types of adjunct displays with two sets of subjects. There was no way to test for differences across all four displays due to the design of our experiments. Instead, the memory test scores were analyzed using independent samples t-tests to see if type of adjunct display viewed would differentially affect performance on the two types of memory tasks (verbal and spatial). The comprehension test scores were analyzed using mixedmodel multivariate analyses of variance, with fact and inference scores as the dependent measures. All statistical tests were conducted at the a Å .05 level of significance. For ease of interpretation, raw scores have been converted to percentage correct scores in the tables.

Results and Discussion

Memory Test Scores Table 1 presents means and standard deviations for scores on the memory test for the two groups. For the text condition, students did not perform differently on the two types of memory tasks, t(66) Å .05, SE Å .20. This finding confirmed our hypothesis that viewing text would involve processing using both the sketchpad and the loop due to the concrete nature of the

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

228


MEANS

AND

STANDARD DEVIATIONS BY ADJUNCT DISPLAY

TABLE 1 PERCENT CORRECT SCORES ON THE MEMORY TEST FOR GROUPS IN EXPERIMENTS 1a AND 1b FOR

Memory task group Experiment 1a

Adjunct display Text Graphic organizer

1b

Outline Concept map

Verbal

Spatial

M SD M SD n

79 20 96 13 35

80 20 87 19 33

M SD M SD n

98 8 90 16 41

70 21 67 20 32

material. For the graphic organizer condition, however, there was a difference in performance on the two tasks. Students in the verbal group performed better than did those in the spatial group, t(66) Å 2.21, SE Å .16. This means that viewing a graphic organizer interfered more with performance on a spatial task than it did for a verbal task and suggests that graphic organizers are processed in a way that involves using the sketchpad, whereas text is not. Thus, the CR hypothesis may explain the ADE for graphic organizers, in addition to pictures and geographic maps. Comprehension Test Scores Table 2 presents means and standard deviations for scores on the comprehension test for the two groups. The main effects for memory task and display were not significant, Wilk’s Lambda Å .991 and .998, respectively; both Fs(2,65) õ 1. The failure to find an ADE for the graphic organizer condition was probably due to the interference from the memory task. Most important was the failure to find a significant memory task by display interaction effect, Wilk’s Lambda Å .999, F(2,65) õ 1. If we had found that students in the spatial memory task group performed worse when viewing graphic organizers than when viewing text, then this would have provided more evidence of spatial interference. This nonsignificant interaction indicates that type of memory task did not differentially affect performance within each display condition. Overall, the results on the comprehension test suggest that students’ attempts to comprehend were not affected by either the type of memory task they were performing or the type of adjunct display they were viewing. Instead, it appears that students’ attempts to maintain a dot configuration in working memory were affected

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

229


TABLE 2 MEANS AND STANDARD DEVIATIONS FOR PERCENT CORRECT SCORES ON THE COMPREHENSION TEST BY REPRESENTATION TYPE AND ITEM TYPE FOR MEMORY TASK GROUPS IN EXPERIMENTS 1a AND 1b Memory task group Experiment 1a

Adjunct display Text

Item Fact Comparison

Graphic organizer

Fact Comparison

1b

Outline

Fact Comparison

Concept map

Fact Comparison

Verbal

Spatial

M SD M SD M SD M SD n

70 20 65 18 70 19 64 16 35

67 23 63 22 68 17 62 16 33


59 19 65 16 69 19 67 22 41

63 17 61 18 67 23 64 22 32

by the type of display they were viewing, with the graphic organizers causing more interference than the texts. Of the two scenarios that would have provided evidence that graphic organizers are processed using the sketchpad, only one, that students’ performance on the spatial memory task would be worse than their performance on the verbal memory task when they viewed graphic organizers, but not when they viewed text, proved to be true. The other — that students in the spatial memory task group would perform worse on the comprehension test when they viewed graphic organizers, but not when they viewed text, did not hold true. This failure to find both differences in memory and comprehension performance does not necessarily mean that graphic organizers are not processed using the sketchpad. Rather, it probably reflects a tendency of the students to concentrate more on the memory task than the comprehension task. This is supported by comparing students’ performance on the memory task (over 80%) to their comprehension task performance (around 70%). The results of Experiment 1a lend partial support to the CR hypothesis as a possible explanation for the ADE in the sense that another type

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

230


of adjunct display (besides pictures and geographic maps) appears to be processed differently than text. However, graphic organizers are not the only type of adjunct display. Outlines and concept maps are also common types of adjunct displays that have received attention as text facilitators. Although concept maps would seem to use space to convey meaning as much as graphic organizers, outlines would appear to rely less on space. Robinson and Schraw (1994) stated that both outlines and text are different from graphic organizers in the sense that both are linear, rather than spatial displays. To provide further support for the claim of Kulhavy et al. (1992) that CR may explain the ADE with other types of adjunct displays, we must demonstrate that other types of adjunct displays besides graphic organizers are also processed using the sketchpad. EXPERIMENT 1b

Experiment 1b was designed to address the issue of whether outlines and concept maps are also processed using the sketchpad. Instead of including a text condition again, we decided to use the null results from Experiment 1a where the two groups did not differ on the memory task when viewing text as a benchmark to compare with the performance of students viewing the outlines and concept maps. In other words, if performance on the spatial task was worse than performance on the verbal task when viewing either concept maps or outlines, we would conclude that the display was processed in a way similar to graphic organizers (spatially). If, however, there was no difference in performance on the memory tasks, we would conclude that the display was processed in a way similar to text. Of course a third possible outcome would be if performance on the verbal task was worse than performance on the spatial task, but because this did not occur previously with the text condition, we were not optimistic about finding this result. Method

Design and Subjects The design was identical to that used in Experiment 1a. The subjects were 73 different student volunteers attending a large public university in the South, with about an equal number of males and females in the sample. Students were randomly assigned to between-subjects conditions. Cell sizes are presented in Tables 1 and 2.

Materials Comprehension tests, memory representations, and memory tests were identical to those used in Experiment 1a. Adjunct displays were constructed from the 10 original texts: 5 were randomly chosen to be outlines; the remaining 5 were chosen to be concept maps. Examples of an outline and a concept map, each constructed from the text in Fig. 1, are displayed in Figs. 5 and 6, respectively.

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP


231

FIG. 5. Outline.

Procedure The procedure was identical to that used in Experiment 1a.


Memory Test Scores Table 1 presents means and standard deviations for scores on the memory test for the two groups in Experiment 1b. As in Experiment 1a with the graphic organizer condition, for both the outline and concept map conditions, students in the verbal group performed better than did those in the spatial group, t(71) Å 7.87, SE Å .14; and t(71) Å 5.60, SE Å .16; respectively. Viewing either an outline or a concept map interfered more with performance on a spatial task than it did for a verbal task. Once again supporting the CR hypothesis as an explanation for the ADE with other types of adjunct displays, these findings suggest that both outlines and concept maps are processed using the sketchpad. Comprehension Test Scores Table 2 presents means and standard deviations for scores on the comprehension test for the two groups in Experiment 1b. Once again no significant main effects were found for memory task, Wilk’s l Å .982, F(2,70) õ 1; display, Wilk’s l Å .920, F(2,70) Å 3.03; or memory task by display, Wilk’s l Å .986, F(2,70) õ 1. The failure to find an interaction effect again indicates that type of memory task did not differentially affect performance within each display condition. The results on the comprehension test sug-

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

232


FIG. 6. Concept map.

gest that students’ attempts to comprehend were not affected by the type of memory task they were performing. Instead, it once again appears that students’ attempts to maintain a dot configuration in working memory were not as successful as were their attempts to maintain a set of four digits in working memory due to the spatial processing of both outlines and concept maps. Taken together, the results of Experiments 1a and 1b suggest that graphic organizers, outlines, and concept maps are processed using the sketchpad, whereas text is not. Although outlines appear to be less spatial than both graphic organizers and concept maps, it appears that they use enough space to encourage processing using the sketchpad. This was evident where students in the verbal group outperformed students in the spatial group on the memory test. The three types of adjunct displays are similar in the sense that they are displayed apart from the main body of text. Perhaps it is simply this dissociation from text that accentuates the adjunct displays’ spatial features and encourages spatial encoding.

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

233


MEANS

AND

STANDARD DEVIATIONS BY ADJUNCT DISPLAY

TABLE 3 PERCENT CORRECT SCORES ON THE MEMORY TEST FOR GROUPS IN EXPERIMENTS 2a AND 2b FOR

Memory task group Experiment 2a

Adjunct display Text Graphic organizer

2b

Outline Concept map

Verbal

Spatial

M SD M SD n

84 15 97 11 19

76 19 87 18 23

M SD M SD n

93 14 98 7 22

88 17 80 23 22

We have established that the ADE may be partly explained by the fact that adjunct displays are processed differently than text. In Experiments 1a and 1b, we attempted to disrupt students’ encoding efforts by requiring them to remember a verbal or spatial representation while trying to comprehend expository material. In doing so we found evidence supporting the assumption of the CR hypothesis that spatial information is encoded from adjunct displays. A more critical assumption of the CR hypothesis, however, states that the spatially encoded information is activated during retrieval processes. Because the adjunct display is represented by both spatial and verbal internal representations, attempts to retrieve information that was encoded from the display have a greater probability of being successful. To more accurately test the CR hypothesis as a viable explanation for the ADE, in Experiments 2a and 2b we attempted to disrupt students’ retrieval efforts. Only in this way could we investigate whether persons actually attempt to retrieve information by activating a spatial internal representation as suggested by CR. EXPERIMENTS 2a AND 2b

Experiments 2a and 2b were designed to further test the viability of the CR hypothesis by having students try to remember either spatial or verbal representations while attempting to retrieve information that was encoded as a result of viewing either text, graphic organizers, outlines, or concept maps. Because Experiments 1a and 1b compared text and graphic organizers, and outlines and concept maps, respectively; Experiments 2a and 2b were designed to match these previous experiments with the only change being the order in which materials and tests were presented.

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

234


TABLE 4 MEANS AND STANDARD DEVIATIONS FOR PERCENT CORRECT SCORES ON THE COMPREHENSION TEST BY ADJUNCT DISPLAY AND ITEM FOR MEMORY TASK GROUPS IN EXPERIMENTS 2a AND 2b Memory task group Experiment 2a

Adjunct display Text

Item Fact Comparison

Graphic organizer

Fact Comparison

2b

Outline

Fact Comparison

Concept map

Fact Comparison

Verbal

Spatial


76 17 71 22 72 15 75 21 19

68 18 68 17 70 16 75 21 23


69 15 77 16 60 16 75 13 22

65 20 71 18 57 21 75 18 22

Method

Design and Subjects The design was identical to that used in Experiments 1a and 1b. The subjects were 86 (42 in Experiment 2a and 44 in Experiment 2b) different student volunteers attending a large public university in the South, with about an equal number of males and females in the sample. Students were randomly assigned to between-subjects conditions. Cell sizes are presented in Tables 3 and 4.

Materials All materials were identical to those used in Experiments 1a and 1b.

Procedure The procedure was identical to that used in the Experiments 1a and 1b except for the following changes in the sequence of the 10 events. First, the adjunct display was shown while the experimenter orally read the corresponding text. When the experimenter finished reading the text, the adjunct display was removed and the memory representation was shown on the screen for about 5 s. Then the memory representation was removed and the comprehension test was shown for about 40 s. The students were instructed to mark on their answer sheets ‘‘A,’’ ‘‘B,’’ or ‘‘C’’ to indicate the correct choice. Then the comprehension test was removed and the memory test was shown for about 5 s. Students were instructed to mark on their answer sheets ‘‘A’’ or ‘‘B’’ to indicate which of the two choices was the same as the one they had previously viewed. Students participated in groups of about five for about 30 min.

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP


235


Memory Test Scores Table 3 presents means and standard deviations for scores on the memory test for the four groups in Experiments 2a and 2b. For the graphic organizer and concept map conditions, students in the verbal group performed better than did those in the spatial group, t(40) Å 2.16, SE Å .19; and t(42) Å 3.58, SE Å .20; respectively. Conversely, for the outline and text conditions, performance on the memory task was equal for the verbal and spatial groups, t(42) Å 1.23, SE Å .18; and t(40) Å 1.51, SE Å .22; respectively. As predicted by the CR hypothesis, attempting to retrieve information after viewing either a graphic organizer or a concept map interfered more with performance on a spatial task than it did for a verbal task. This suggests that information encoded from both graphic organizers and concept maps is stored in a spatial format whose activation during retrieval interfered with students’ internal representation of the dot configuration but did not interfere with their representation of the digit sequence. These findings also suggest that information encoded from outlines and text is stored mainly in a verbal format whose activation during retrieval did not interfere with students’ internal representation of the dot display. Thus the CR hypothesis appears to apply only to adjunct displays that are more spatial than either outlines or text. Comprehension Test Scores Table 4 presents means and standard deviations for scores on the comprehension test for the four groups in Experiments 2a and 2b. For Experiment 2a, the main effects for memory task, Wilk’s l Å .955, F(2,39) Å .92; display, Wilk’s l Å .944, F(2,39) Å 1.17; and memory task by display, Wilk’s l Å .976, F(2,39) Å .47, were not significant. For Experiment 2b, the same effects were not significant, Wilk’s lambda Å .980, .874, and .968, Fs(2,41) Å .41, 2.97, and .68, respectively. Again, most important of these are the nonsignificant interaction effects for memory task by display, indicating that type of memory task did not differentially affect performance within each display condition. GENERAL DISCUSSION

The purpose of this study was to investigate whether other types of adjunct displays besides pictures and geographic maps are processed using the visuospatial sketchpad component of working memory, and after they have been processed, whether the information that has been encoded is then retrieved using the sketchpad. In Experiments 1a and 1b, when students viewed either graphic organizers, outlines, or concept maps, those who were required to remember a spatial representation performed worse at that task than students who were required to remember a verbal representation. When students viewed texts, however, there was no difference in the memory performance

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

236


of the two groups. These findings provide evidence that adjunct displays such as graphic organizers, outlines, and concept maps are processed in a way that involves use of the sketchpad. Baddeley (1986) has proposed that spatial representations such as the dot representations used in the present study are processed using the sketchpad, whereas verbal representations such as the digit representations used in the present study are processed using the phonological loop. But what about representations that are mostly verbal and contain few spatial features such as outlines? In the present study we found that outlines are processed using the sketchpad. Perhaps this conflict may be resolved if one considers that the two separate slave systems in working memory may both be involved more or less in the processing of most of the text materials students encounter. For example, students are often able to ‘‘picture’’ where certain text information is located on a page they have previously studied. Similarly, it would be unlikely that a student would view a map or picture and not activate verbal information (a picture is worth ten thousand words). What determines how much each slave system will be involved may be the amount of visuospatial and verbal information that is activated when viewing the representation. In the present study, we found no evidence of processing using the phonological loop more than the sketchpad. As we have previously stated, this may have been due to the highly concrete materials we used. Although our results do not confirm this hypothesis that both the loop and the sketchpad are used to process text materials, it seems reasonable that pictures and words may become more memorable when they evoke more verbal and spatial activation in a way that combines or associates both types of information. This notion is certainly consistent with dual coding theory (Clark & Paivio, 1991). In Experiments 2a and 2b, when students attempted to retrieve information after viewing either graphic organizers or concept maps, those who were required to remember a spatial representation performed worse at that task than students who were required to remember a verbal representation. When students viewed outlines or texts, however, there was no difference in the memory performance of the two groups. These findings provide evidence that information that is encoded as a result of viewing spatial adjunct displays such as graphic organizers and concept maps is stored in a spatial format, and attempts to retrieve this information involve use of the sketchpad. Information encoded as a result of viewing outlines and text, however, is not retrieved in a way that involves the sketchpad, and therefore is likely stored in a verbal format. This indicates that the CR hypothesis does a better job of explaining the ADE for spatial, rather than linear adjunct displays. The results of Experiments 2a and 2b, when combined with the results of the first experiments, suggest the following conclusions. Text is processed in a way that makes no more use of the sketchpad than the loop, and as a result, information that is encoded from text is not retrieved using the sketchpad more than the loop. Outlines are processed in a way that makes more use of the

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP


237

sketchpad than the loop; however, information that is encoded from outlines is not retrieved using the sketchpad more than the loop. Graphic organizers and concept maps are processed in a way that makes more use of the sketchpad than the loop, and information that is retrieved after viewing them is retrieved in a way that makes more use of the sketchpad than the loop. Thus it appears that the proposal made by Kulhavy et al. (1992) that the CR hypothesis may explain the ADE for other types of adjunct displays besides geographic maps is partly correct and partly incorrect. CR states that information in adjunct displays is encoded in both verbal and spatial internal representations. Experiments 1a and 1b provided evidence that outlines, graphic organizers, and concept maps, but not text, are processed using the visuospatial sketchpad. CR also states that when attempts to retrieve the verbal representation fail, the conjointly encoded spatial representation can be successfully retrieved. Experiments 2a and 2b provided evidence that only information from graphic organizers and concept maps, and not outlines or text, is actually retrieved using the sketchpad. Thus, the CR hypothesis seems to explain the ADE for spatial adjunct displays, but does not explain the ADE for linear displays such as outlines and text. Based on our findings, we propose that most text materials (including adjunct displays) are processed both spatially and verbally. Whether text materials are encoded so that an associative link between the two types of information exists in memory, however, is the important issue. Moreover, it is the strength of that link that will determine whether information will be successfully retrieved. Because spatial adjunct displays have more spatial features than text and outlines, the associative link between verbal and spatial features in the memory representations of information encoded when studying spatial adjunct displays will be stronger than those that are encoded when studying linear representations. In other words, some adjunct displays are more effective than others simply because some do a better job of combining verbal and spatial information in a meaningful way. For example, an outline presents information in a hierarchical, linear format, making some use of space to communicate hierarchical concept relations. A graphic organizer, on the other hand, presents information using rows and columns, making more effective and efficient use of space to communicate both hierarchical and coordinate concept relations. Recent research has shown that the ADE might be stronger for adjunct displays that make better use of space to communicate information (Robinson & Kiewra, 1995). It seems unlikely that only one theory may explain the ADE for all types of adjunct displays. However, it is possible that a particular theory (e.g., CR) may explain the ADE for particular types of adjunct displays (e.g., spatial). Ultimately, these theories could be useful in explaining why some types of adjunct displays facilitate memory for related text better than others. Although the present study represents the first attempt, according to

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP

238


our knowledge, to investigate whether studying various types of adjunct displays involves using spatial working memory, it has a few limitations. The first has to do with the experimental conditions. Having students view a representation while they listen to text is not what they actually do when studying. Thus, we could not be sure that students were processing the representations in a way similar to what they actually do. This certainly may have something to do with the failure to find an ADE on the comprehension tests. Where other studies have found that students perform better on comprehension tests when viewing graphic organizers as compared to text (e.g., Robinson & Schraw, 1994), no advantage was found in our study. In our view this was probably due to the interference from the memory task. Usually students are not trying to remember exact information when they begin study (unless you consider what happens during final exam week!). We feel that this additional task probably prevented students from fully taking advantage of the adjunct displays, thus resulting in no ADE. A second limitation is that the verbal task may have been easier than the spatial task, thus demanding less resources. An inspection of Table 1, however, reveals that the two tasks were equal in difficulty when students viewed text, but not when students viewed the other displays. In terms of the implications this study has for educators and instructional designers, we recommend that adjunct displays be carefully chosen so that they make meaningful use of space. For future research, studies should continue to investigate how the visuospatial sketchpad may be used effectively in aiding comprehension of text and how adjunct displays should be constructed to take full advantage of this mostly untapped resource. REFERENCES BADDELEY, A. (1986). Working memory. Oxford: Oxford University Press. BADDELEY, A. (1992). Is working memory working? The Fifteenth Bartlett Lecture. Quarterly Journal of Experimental Psychology, 44a, 1–31. BADDELEY, A. D., & HITCH, G. J. (1974). Working memory. In G. Bower (Ed.), Recent advances in learning and motivation (Vol. 8, pp. 47–90). New York: Academic Press. BEHRENS, J. T., MULVENON, S. W., ROBINSON, D. H., WHITE, M. C., & STOCK, W. A. (1990, June). Quantitative textual and graphic information affect recall across representations. Paper presented at the annual meeting of the American Psychological Society, Dallas, TX. CLARK, J. M., & PAIVIO, A. (1991). Dual coding theory and education. Educational Psychology Review, 3, 149–210. CORKILL, A. J. (1992). Advance organizers: Facilitators of recall. Educational Psychology Review, 4, 33–67. DARCH, C., & GERSTEN, R. (1986). Direction-setting activities in reading comprehension: A relation of two approaches. Learning Disabled Quarterly, 9, 235–243. EGGEN, P., & KAUCHAK, D. (1994). Educational psychology: Classroom connections. New York: MacMillan. GATHERCOLE, S. E., & BADDELEY, A. D. (1993). Working memory and language. Hove, U.K.: Erlbaum. HERBER, H. L., & SANDERS, P. L. (1969). Research in reading in the content areas: first year report. Syracuse University: Reading and Language Arts Center.

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP


239

KRULEY, P., SCIAMA, S. C., & GLENBERG, A. M. (1994). On-line processing of textual illustrations in the visuospatial sketchpad: Evidence from dual-task studies. Memory & Cognition, 22, 261–272. KULHAVY, R. W., STOCK, W. A., PETERSON, S. E., PRIDEMORE, D. R., & KLEIN, J. D. (1992). Using maps to retrieve text: A test of Conjoint Retention. Contemporary Educational Psychology, 17, 56–70. KULHAVY, R. W., LEE, B. J., & CATERINO, L. C. (1985). Conjoint Retention of maps and related discourse. Contemporary Educational Psychology, 10, 28–37. LAMBIOTTE, J. G., DANSEREAU, D. F., CROSS, D. R., & REYNOLDS, S. B. (1989). Multirelational semantic maps. Educational Psychology Review, 1, 331–367. LEVIE, W. H. (1987). Research on pictures: A guide to the literature. In D. M. Willows & H. A. Houghton (Eds.), The psychology of illustration: I. Basic research (pp. 1–50). New York: Springer-Verlag. LEVIN, J. R., & MAYER, R. E. (1992). Understanding illustrations in text. In B. Britton (Ed.) Learning from textbooks (pp. 95–113). Hillsdale, NJ: Erlbaum. PAIVIO, A. (1986). Mental representation: A dual coding approach. New York: Oxford Univ. Press. ROBINSON, D. H., & KIEWRA, K. A. (1995). Visual argument: Graphic organizers are superior to outlines in improving learning from text. Journal of Educational Psychology, 87, 455– 467. ROBINSON, D. H., & SCHRAW, G. (1994). Computational efficiency through visual argument: Do graphic organizers communicate relations in text too effectively? Contemporary Educational Psychology, 19, 399–415. WINN, W. (1991). Learning from maps and diagrams. Educational Psychology Review, 3, 211– 247.

ab01$$0903

05-21-96 08:52:42

cepal

AP: CEP