the processing of organizational and component step information in written directions

JOURNAL OF MEMORY AND LANGUAGE 26, 24-35 (1987)

The Processing of Organizational and Component Step Information in Written Directions

PETER DIXON

University qf Albertu. Edrnonron, Albertu T6G 2E9. Canada

Procedural directions are read faster when general organizational information is found at the beginning rather than at the end of the directions. Two possible explanations for this effect are investigated in the present research. In the guessing account, readers need extra time to guess the relationships of component steps when the organizational information is not found at the beginning. In the buffering account, readers buffer the component step information until the organizational information is found, and only then incorporate the component steps into their mental representation. The two accounts were tested by measuring reading time separately for organizational and component step information. Most of the information-order effect occurred while subjects were reading the component step information. Moreover, the magnitude of the effect was related to how difficult it was to guess the relationships among component steps when read in isolation. Together the results support the guessing explanation, and suggest that readers attempt to interpret component steps immediately, even if that initial interpretation might be incorrect. Lb 1987 .Academic

Directions for carrying out tasks often contain two qualitatively different kinds of information. The first might be termed component step information, the specific enumeration of the actions needed to perform the task. Another kind of information might be termed organizational information, information about the overall structure and organization of the task. Organiza- tional information indicates how the component steps are related to each other and how they go together to accomplish the task at hand (cf. Smith & Goodman, 1984). For instance, consider the direction, “You can make a wagon by drawing a long rectangle with two circles underneath.” Here the component steps consist of drawing a long rectangle and putting two circles underneath it. These are the specific actions

This research was supported by Grant A8263 from the Natural Sciences and Engineering Research Council of Canada. 1 thank Gay Bisanz for comments on an earlier version of the paper, and Judie Shedden and Linda Mrkonjic for running subjects and scoring responses. Requests for reprints should be sent to Peter Dixon, Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9. Canada.

used in performing the task. The organizational information is that these component steps go together to form a picture of a wagon. One’s knowledge of what wagons look like presumably allows one to infer the relationships among the component steps, such as the relative sizes of the circles and rectangle, their placement, and so on. The experiments reported in this article investigated how component step and organizational information are used in constructing a mental representation, or plan, for carrying out a task.

The principal tool in this investigation is the “information order” effect studied by Dixon (1982, in press, a, b). In this effect, single sentence directions are read faster when they begin with one piece of information rather than another. For instance, directions such as, “You can make a wagon by drawing a long rectangle with two circles underneath” took 7.3 s to read, while the reverse order, “By drawing a long rectangle with two circles underneath you can make a wagon,” took 9.0 s (Dixon, in press, b). This effect does not seem to be due to order of the main and subordinate

24 0749-596X187 $3 .OO Copyright 6 1987 by Academic Press. Inc. All rights of reproduction in any form reserved.

PROCESSING WRITTEN DIRECTIONS 25

clauses, nor to the temporal order in which the information might be used in carrying out the task (Dixon, 1982, in press, a). In- stead, the effect may be related to how organizational and component step information is used in constructing mental plans.

I will consider two different accounts of the information order effect in this article. Both assume that the role of organizational information is to provide a framework or schema for interpreting and relating the component step information. The most natural way of constructing a mental plan would be first to use the organizational information to set up a plan schema, and then to incorporate the component step information into that schema. For instance, if one knew that a drawing of a wagon were to be made, one would expect to find components of the drawing that correspond to the body of the wagon and the wheels. The component step information would then be interpreted in terms of these expec- tations.

If the component step information is encountered first in the sentence, readers might adopt one of two strategies. A buffering strategy would be to retain the component step information in a relatively uninterpreted form until the organizational information is found. After the organizational information has been processed, the component steps can be added to the mental plan as before. (In this context “uninterpreted” means that decisions about fea- tures such as the relative size, placement, and orientation of the components have not been made.) The buffering strategy may cause the information order effect because buffering requires processing resources, and the reading process may be slower while the buffering is going on.

Another possible reason why buffering may lead to slower reading times for components-first sentences was suggested by Dixon (in press, a). When the component steps have to be buffered, the opportunity for parallel processing is reduced. When information is found in the order in which it

is used in planning, plan construction can overlap with other reading processes, and the plan can be completed shortly after the end of the sentence is reached. But if the information is out of order, the component step information must be buffered until the organizational information is found. If it is encountered near the end of the sentence, the component step information cannot be incorporated into the plan until sometime after the rest of the sentence is processed. The net effect would be to extend the total processing time for the sentence.

A second possible strategy for dealing with components-first sentences might be termed a guessing strategy. In this ap- proach readers try to guess how the component steps are organized and related, rather than waiting for the organizational information in the sentence. These guesses might be based on conjectures about what the overall configuration is supposed to look like, or default assumptions about how the components should be drawn. Pre- sumably, these guesses can be corrected later if they turn out to be incorrect. The guessing strategy assumes that the component steps are interpreted as soon as they are found. In this sense it is related to the “processing immediacy” assumption pro- posed by Just and Carpenter (1980); they both incorporate the idea that information is processed as fully as possible as soon as it is encountered in the text. Similarly, the process of correcting erroneous guesses may be related to the error recovery strategies reported by Carpenter and Daneman (1981).

The guessing and buffering accounts make different predictions about whether the extra time involved in processing components-first sentences is due to added difficulty in processing the component step information, or added difficulty in processing the organizational information. If the guessing account is correct, the additional time would be needed while reading the component step information at the beginning of the sentence. The assumption is

26 PETER DIXON

that readers are generating guesses about the organization of the steps during this interval, and that this process contributes the extra time. On the other hand, the buffering account makes the opposite prediction. It predicts that the extra time would be needed during processing of the organizational information in the second part of the sentence. For example, processing resources might be less available at this point because they are tied up in buffering the component steps. These predictions were examined in Experiment 1.

EXPERIMENT 1

In Experiment 1 directions for making simple drawings were split into two parts and a reading time was collected for each. The buffering account predicts longer organizational reading times when the component steps are presented first, while the guessing account predicts longer component step reading times. A second purpose of this experiment was to test whether the information-order effect is a sentence-level effect, or a discourse-level effect. That is, can the same effect be obtained when the two kinds of information are presented in separate sentences?

In this experiment the organizational information consisted of the name of a common object to be drawn, and will be termed the abject sentence. The components steps were descriptions of how to draw parts of the object. The directions used by Dixon (in press, b) were rephrased as two sentences, one with the object (e.g., “This will be a picture of a wagon”) and one with the component steps (e.g., “Draw a long rectangle with two circles underneath”). The two sentences could appear in either the object-first order, or the components-first order, and reading times were collected for each.

Method

On each trial of this experiment subjects read and carried out two-sentence directions for drawing simple schematic pic-

tures. One sentence named an object to be drawn; the other described the component steps necessary to make the drawing. These will be referred to as the object and components sentences, respectively. After reading each pair of sentences, subjects carried out the directions by drawing the object in the appropriate area in a response booklet.

Subjects sat in front of a video monitor. When they were ready to begin they pressed a button and held it down. After 0.5 s either the object sentence or the component sentence appeared on the screen. When they had finished reading the sentence, subjects released the button and the sentence also disappeared when the subject appeared 0.5 s after subjects pressed and held down the button a second time. This sentence also disappeared with the subject released the button. After reading both sentences, subjects carried out the directions by drawing the indicated object in a response bookiet. Reading time for each sentence was defined as the length of time the sentence was on the screen. Drawing time was measured from when the second sentence disappeared to when subjects pressed the button to get the first sentence in the next set of directions. Subjects were asked to press the sentence button with their preferred hand so that reading and drawing time could not overlap.

Trials were controlled by an Apple II mi- crocomputer system that recorded the reading and drawing times in seconds/lOO. The sentence display was produced on a 30-cm black-and-white monitor on two 40- character lines using upper and lower cases. At a typical viewing distance of 50 cm, each letter space subtended about 0.7” of horizontal visual angle, and the two lines were separated by about 1.4” vertically. Each page of the response booklet was divided into 10 numbered boxes measuring 10.8 by 5.6 cm.

Each subject read and carried out all of the 60 sets of directions shown in the Ap- pendix. On half the trials the object sen-


tence was presented first, and on the other half the components sentence was presented first. The assignment of object/components order to direction set was done randomly for each subject. This procedure deliberately confounded variance due to subjects with variance due to materials, and ensured that the results would generalize to both the subject and materials pop- ulations.

Analyses were conducted on the median reading times and drawing times for each subject and sentence order. The drawing times turned out to be quite variable; no significant effects were found, and they will not be discussed further. In addition to the time data, subjects’ drawing responses were scored for accuracy. Three kinds of errors were distinguished. Component errors were those in which one or more of the component steps were performed in- correctly. Object errors were those in which the component steps were techni- cally correct, yet the completed drawing was not a reasonable depiction of the intended object. Miscellaneous errors in- cluded omissions (in which subjects failed to draw anything), and elaborations (in which details or extraneous lines were added to the drawing). Counts of each type of error were analyzed separately.

Subjects were 24 undergraduates at the University of Alberta, all of whom were native English speakers. Data from one subject were not used because of error rates greater than 50%.

Results

The reading times for the object and components sentences are shown in Figure 1. Overall, the sentences were read faster when the object sentence was presented first (F(1,22) = 53.06, p < .OOl). However, this effect interacted with the type of sentence (F(1.22) = 16.72, p < .005); there was a significant difference between the object-first order and the components-first order for the components sentences (F(1,22) = 41.67, p < .OOl), but not for the

7.0

6.0

c Object Sentence

2.0 n

.

Object First

Object Second

FIG. 1. Reading times and error rates in Experi- ment 1.

object sentences (F( I ,22) = 1.77). Also, object sentences were read faster than components sentences in genera1 (F( 1,22) = 101.43, p < .OOl), due to the greater length of components sentences.

Object, component, and miscellaneous errors are shown in Figure 1 as well. There were significantly more object errors when the object information was presented second (F(1,22) = 9.51, p < .Ol). Although the number of such errors was small, subjects made almost twice as many of them when the components sentence was presented first. There were no significant differences for the other two error types.

The overall faster reading rate for the object-first sentence order demonstrates that directions are easier to understand when they begin with general organizational information, rather than specific component steps. The results replicate previous research with this task (Dixon, in press, b), and show that the effect holds regardless of whether the two kinds of information are presented in the same sentence or in separate sentences. This suggests that the effect is caused by the process of using the infor-

28 PETER DIXON

mation to construct mental plans, rather than by local sentence comprehension processes.

The fact that the reading time effect is larger with the components sentence supports the guessing hypothesis outlined earlier. That is, when subjects read the components sentence first, without the benefit of knowing what object is intended, they generate guesses about what the overall drawing is supposed to look like and how the component steps relate to each other. This relational information allows them to interpret and understand how the component steps are to be carried out. Extra time is needed to generate these guesses, and consequently the reading times are longer.

Because of the variability of the data, it is not possible to conclude that there was no effect of information order on object sentences. Although the difference between object-first and components-first directions was not significant, a 95% confi- dence interval for the difference extended from - 118 to 538 ms. Thus, a fair-sized information order effect on object sentences is still plausible given these data. In fact, such a result would be consistent with the guessing strategy: Additional time would be needed on object sentences whenever subjects use the object information to correct erroneous guesses. The guessing strategy predicts only that the predominate source of additional time should be processing of the components sentence.

The pattern of error rates also supports the hypothesis that subjects generated guesses when the components sentences were presented first. There were no differences between the two sentence orders in subjects’ ability to carry out the component steps. However, there was a significant difference in how well the drawing resembled the intended object. These object errors might occur if subjects failed to correct an erroneous guess about the nature of the drawing. The drawing would then reflect the initial faulty interpretation of the components sentence.

This process can be illustrated with a specific example. Figure 2a shows the response generated by a subject for the directions, “This will be a picture of a wine glass. Draw a triangle on top of an upside- down T.” Figure 2b shows an object error generated by a subject who read the directions in the reverse order, “Draw a triangle on top of an upside-down T. This will be a picture of a wine glass.” The drawing suggests that the subject misinterpreted how the drawing was supposed to look initially, and then failed to correct that interpretation when he or she found out it was supposed to be a wine glass. It is interesting to note that the erroneous orientation of the triangle is probably the canonical or “default” orientation for triangles. Presum- ably, the triangle was drawn that way because the subject had no indication that the triangle should deviate from the typical orientation when the components sentence was first read.

The reading time and error data argue against the buffering hypothesis as an explanation of the information-order effect. If the extra time involved in processing directions beginning with component step information was due to the additional resources needed to buffer the component sentences, one would have expected the reading time effect to occur primarily while the buffering was going on, that is, during the reading of the second, object sentence. However, just the opposite result was found. Similarly, if the extra time were related to the failure to overlap plan construction and other reading processes, one would have expected the additional time to occur at the

- I _

(a) (b)

FIG. 3. (a) Example of a correct response to “This will be a picture of a wine glass. Draw a triangle on top of an upside-down T.” (b) Example of an object error to the components-first version of the same direction.

PROCESSING WRITTEN DlRECTIONS 29

end of the directions, when the deferred plan construction finally takes place. Al- though an undetected effect of information order may have occurred on object sentences, the buffering account has trouble explaining the much larger effect obtained on components sentences. Also, a buffering account would probably predict that any error rate differences would be related to the loss of component step information during the buffering. Thus, an effect would be predicted for component errors rather than object errors.

It is somewhat surprising that subjects ever made object errors like that shown in Figure 2b. Why would a subject make such a drawing, after just reading that the drawing was supposed to be a wine glass? One possibility is that although subjects were aware of the inappropriateness of such drawings, they were nonetheless unable to infer what was wrong with their mental plan. For instance, after reading the second, object sentence, they may have no longer remembered the wording of the initial, components sentence. Consequently, they would have been unable to infer what aspects of their faculty plan were dictated by the components sentence, and which were dictated by the interpretation they had generated. Under such circumstances subjects may have resorted to executing the plan they had constructed, even though it seemed to be inconsistent with the intended object.

This explanation suggests that there may have been a strong effect of the sentence boundary on memory. For example, a number of researchers have suggested that verbatim memory of sentences is purged after the end of the sentence is reached and the information has been integrated with the preceding text (e.g., Thibadeau, Just, & Carpenter, 1982; Perfetti, 1985). Support for this notion comes from experiments on listening comprehension (Jarvella, 197 I ; Perfetti & Goldman, 1976). Subjects in these experiments were stopped during listening and asked to recall the word in the

passage that followed a given probe word. Performance was worse when the target was in the preceding sentence than when it was in the current sentence, even when the same number of words intervened. Similar results were obtained by Goldman, Hoga- boam, Bell, and Perfetti (1980) in reading comprehension. Thus, after a sentence has been read, subjects may remember their interpretation of the sentence, but not the ac- tual words used.

EXPERIMENT 2

The time and error rate results found in Experiment I could conceivably be specific to directions that are divided into two sentences. For instance, subjects may only generate guesses about organizational information when it is necessary to understand the current sentence. They may not need such guesses when the organizational information can be found later in the same sentence. In other words, subjects may generate guesses only when they reach the end of the first components sentence without finding the necessary information.

To test this hypothesis, Experiment 1 was replicated using single-sentence ver- sions of the directions. Separate reading times were collected for the clause containing the object and the clause containing the components. Two types of sentences were constructed for each direction shown in the Appendix. In object-embedded sentences the object information was embedded in a subordinate clause (e.g., “To make a wagon draw a long rectangle with two circles underneath”). In components- embedded sentences the component steps were embedded in a subordinate clause (e.g., “You can make a wagon by drawing a long rectangle with two circles underneath”). In both cases the sentences were presented with either the object clause first or the component clause first. This experiment was similar to the one run by Dixon (in press, b), except that reading times were collected separately for the two clauses of the sentence.

30 PETER DIXON

Method Results

The procedure was similar to that in Experiment 1. On each trial, subjects pressed and held down a sentence button. After 0.5 s the direction appeared. The en- tire sentence was presented on the screen, but in the second part of the sentence all of the letters and punctuation marks were replaced with X’s. When subjects wanted to go on to the second clause of the sentence, they momentarily released the button and pressed it again. After 0.25 s a new display was presented in which the letters and punctuation in the first part of the sentence were replaced by X’s and the second part of the sentence was shown normally. When subjects were finished with the second part they released the button and the sentence display disappeared. Subjects then carried out the direction. Reading time for the first part of the sentence began when the first display was shown and ended when the sentence button was tirst released. Reading time for the second part was defined similarly.

As in Experiment I, there was an overall advantage for the object-first sentences (Ff1,27) = 22.67, p < .OOl). and an interac- tion with the object/components part of the direction (F(1,27) = 8.44, p < .Ol). How- ever, unlike Experiment 1, both the object and component parts were read significantly faster when the object information was first (F(l,27) = 5.33, p < .05 for the object clause, and F(1,27) = 16.79, p < .OOl for the components clause). Due to its greater length, the components clause took longer to read than the object clause (F( 1,27) = 162.69, p < .OOl). Finally, object-embedded sentences were read faster than component-embedded sentences (F(l,27) = 9.56, p < .005). Again this was probably due to differences in length.

The stimuli consisted of the 60 sets of directions shown in the Appendix. Four sentences were prepared for each set of directions. In the object-embedded sentence the object to be drawn was described in a subordinate clause. In the components-embedded sentence the component steps were described in a subordinate clause. Both sentence structures were used in an object- first version and a components-first version. Each subject read and carried out 60 directions, 15 with each type of sentence. As in Experiment I, the assignment of direction set to sentence type was done randomly for each subject. The apparatus, procedure, and data analysis were the same as in Experiment 1.

Error rates are also shown in Figure 3. Unlike Experiment 1, there was no ten- dency for more object errors to occur with components-first sentences (F(1,27) = 0.76). The effect of information order on object errors was significantly different in Experiments 1 and 2 (t(49) = 2.10. p < .05).

7.0

6.0

5.0

2.0

Subjects were 30 native English-speaking undergraduates at the University of Al- berta. Data from one subject were not used because of an error rate greater than 50%. Data from another subject were not used because the subject added extraneous lines and details to over 20% of the drawings.

FIG. 3. Reading times and error rates in Experi- ment 2.

n . Object Embedded

0 0 Component Embedded

Component Errors

Miscellaneous Errors

Object First

Object Second


Discussion

The reading time results were generally similar to those obtained in Experiment 1; most of the information order effect occurred while processing the components information rather than the object information. This supports the guessing account described previously, and indicates that it is not limited to situations in which the two kinds of information are in different sentences. However, in this experiment there was clear evidence that the object clause, as well as the components clause, took longer to read in components-first sentences. This result is consistent with the guessing hypothesis; it may simply mean that subjects sometimes have to correct their guesses based on the object information, and that this correction takes time.

One difference that did occur between Experiments 1 and 2 was that the effect of information order on object errors was significantly less in Experiment 2. As outlined earlier, the object-error effect in Experi- ment I may have occurred because subjects sometimes did not retain the specific wording and content of an initially presented components sentence, and thus were not able to use the object sentence to correct erroneous interpretations. The lack of such an effect in Experiment 2 suggests that the specific wording was more often available when the object and component steps were in the same sentence. In other words, verbatim memory of the component steps may be better when there is no inter- vening sentence boundary (as in Experi- ment 2), than when there is a boundary (as in Experiment 1).

The results of this experiment also dis- count an alternative explanation of the information-order effect found by Dixon (in press, b). In this earlier experiment, sentences like those used here were presented in a single display, and as expected, components-first sentences took longer to read. One possible account of the effect was that subjects preferred to read the object information first, and if the direction began with

the components instead, they skipped quickly through the sentence until the object information was found, read it, and then went back to read the initial part of the sentence. Reading the sentence in reverse order in this way presumably would take additional time. However, this strategy was not possible in the present experiment because the first part of the sentence could not be reread once a subject had gone on to the second part. Because this experiment replicated the earlier pattern of results, it seems unlikely that a “reverse-reading” strategy was responsible for the effect.

EXPERIMENT 3

According to the guessing account, the size of the information-order effect should be related to how difficult it is to generate guesses about how the component steps are related. For those sentences with easily interpretable component steps, the order of the two types of information should not matter too much, and a relatively small information order effect should be found. But if the component steps are difficult to interpret by themselves, having the organizational information presented first should be a large advantage. In other words, the sentences that show the largest information- order effect should be those in which guessing the relationships among component steps is difficult or problematic.

This prediction was tested in Experiment 3. Subjects were asked to carry out the component steps from Experiment 1 without the benefit of any organizational information. The hypothesis was that there should be a significant correlation across sentences between the number of object errors in this experiment and the size of the information-order effect in Experiment 1. This would indicate that the biggest advantage of having organizational information first occurs when the component steps are difficult to interpret by themselves. An- other measures of how easy it is to guess how the component steps are related is whether subjects can correctly identify the object after they have drawn it. Presum-

32 PETER DIXON

ably, if subjects can guess the object after reading only the component steps, there should be little advantage to providing the object information first.

This experiment also tested another version of the buffering account. According to this version, the information-order effect occurs primarily with component steps because extra time is needed to memorize or store this information when it is presented prior to the organizational information. Be- cause the component steps are stored in an uninterpreted form, there should be little relationship between the time to carry out these storage operations and how difficult the component steps are to understand and follow by themselves. Rather, it is more likely that the information-order effect would be related to the length of the components sentences. Thus, the buffering account would be supported if the information-order effect correlates with the number of words in the components sentences.

Method

The component step sentences from Ex- periment 1 were printed in booklets, five per page. Subjects were told that each direction described how to draw a simple picture of a common object. They were asked to carry out each direction in the space provided, and if possible, to identify the object being depicted. Each subject received a different random order of sentences. Responses were scored for object and component errors using the same cri- teria as before. Identity responses were scored as correct if the subject responded with the intended name of the object or a close synonym. Subjects were 20 native English-speaking undergraduates at the University of Alberta.

Results and Discussion

Table 1 shows the mean and standard de- viation (across sentences) for object errors, component errors, identification errors. and number of words. As can be seen by comparing Table 1 to Figure 1, the number

TABLE I RESULTSOFEXPERIMENT~

~____ ________~ ~_~ -~- Correlation with

information-order Mean SD effect

% Object errors 42.4 28.4 .3369* % Component errors 5.8 9.8 - .I697 % Identification

errors Number of words

* p < .Ol.

71.8 26.4 - ,003s 11.3 1.7 - .0767

of object errors in Experiment 3 (without organizational information) was substan- tially larger than it was in Experiment 1 (with organizational information; t(41) = 40.75, p < .OOl). Clearly, the organizational information is often needed to construct reasonable drawings of the intended object. There was no difference between Experi- ments 1 and 3 in the number of component errors (t(41) = 0.54).

The last column in the table shows the correlation with the information-order effect from Experiment 1. As predicted by the guessing account, the effect correlated with the percentage object errors in the present experiment. However, the information-order effect did not correlate with identification errors. This suggests that the identity of the object as such may not be important in producing the information- order effect. Instead, it may be the information about the organization of the component steps, implicit in the object identity, that is crucial. Thus, very little information-order effect would be found for components sentences that are easy to interpret and organize correctly, even if the object cannot be identified.

There was little evidence that either component errors or number of words was related to the size of the information-order effect. Both of these variables might have been expected to be important if the buffering account were correct. If subjects at- tempted to memorize the components sentence, longer sentences should have taken more time and led to more of an information-order effect. The number of compo-


nent errors would also be an index of the difficulty of the components sentence, and might be related to the amount of time needed to store or buffer it. The fact that neither correlation even approached signifi- cance suggests that the buffering account is not an adequate description of the data. Overall, the results are more in favor of the guessing account.

GENERALDISCUSSION

The results of the three experiments offer clear evidence about how organizational and component information is processed while reading directions. In Experi- ments 1 and 2, components-first directions took longer to understand than object-first directions. The slower reading rates occurred primarily with the component information, suggesting that subjects needed extra time to guess the relationship of the components when they were not told the object at the outset. The errors in Experi- ment 1 were consistent with this analysis: When the components came first, subjects were more likely to misinterpret how they went together to depict the object. In Ex- periment 2, the object-error effect was traded for an increase in reading time on object clauses. One interpretation of this result is that subjects were more often able to revise an erroneous interpretation of the component information when the organizational information occurred within the same sentence. In the third experiment, component steps about which it was difficult to generate guesses tended to be those that showed the largest information-order effect. Thus, the guessing hypothesis provides a consistent account of all three experiments.

The information order effect studied here is consistent with the theoretical framework described by Dixon (in press, a, b). In this framework, mental plans are assumed to have a hierarchical structure, with general intentions at the top level and the specific actions needed to carry out that inten- tion at the lower levels (Miller, Galanter, & Pribraum, 1960; Sacerdoti, 1977; Wilensky,

1983). Each lower level relines in more de- tail the actions outlined at the upper level; thus, the most natural way to construct the mental plan representation is from the top down. Additional processing is required whenever low-level information is provided prior to the high-level information.

The present results lit with this general framework if organizational information is thought of as high-level information, and component step information is thought of as relatively low-level information. In this view, the object sentence provides a general description of what is being done in the task as a whole (e.g., “Make a wagon”), and the component steps provide information about how to do specific parts of the task (e.g., “Draw a long rectangle” and “Draw two circles underneath”). Thus, there is a hierarchical part-whole relationship between the component steps and the organizational information. Although the hierarchy in this case consists of only two levels, it may still be the case that the mental representation is constructed from the top down, and that the high-level, organizational information is needed before the low-level, component steps. The present results extend the hierarchical planning framework by providing evidence for a mechanism, the guessing strategy, that accounts for the additional time needed to process sentences beginning with low-level information.

If the present results generalize to other tasks and materials, they may have some important practical implications. They suggest that one source of errors in following directions is the misinterpretation of how component steps are organized and interre- lated with each other. Although the users of the directions may be perfectly able to understand each component step, they may have little appreciation for the overall structure of the task and may perform poorly as a consequence. The present results suggest that this problem could be al- leviated by providing initially some high- level information about the nature and organization of the task. Such information

34 PETER DIXON

should minimize errors of interpretation such as those found in Experiment 1.

APPENDIX

Experiment 1: Stimulus Materials

This will be a picture of a house. Draw a rectangle with a triangle on top.

This will be a picture of a wagon. Draw a long rectangle with two circles underneath.

This will be a picture of the sun. Draw a circle with six lines extending outward.

This will be a picture of a cup. Draw a square with a small half-circle on one side.

This will be a picture of an ice cream cone. Draw a triangle pointing downward and put a half-

circle at the top.

This will be a picture of a bowling ball. Draw a circle with three smaller circles together in-

side it.

This will be a picture of a pine tree. Draw a triangle pointing upward and a small square

beneath it.

This will be a picture of a traffic light. Draw a tall rectangle with three circles inside it.

This will be a picture of a window. Draw a square and divide it with a horizontal and a

vertical line.

This will be a picture of a suitcase. Draw a rectangle and put a small half-circle on top.

This will be a picture of the side view of an igloo. Draw a half-circle with a small square on one side.

This will be a picture of a fish. Draw a long oval and put a triangle at one end.

This will be a picture of the side view of a bed. Draw a long rectangle and at one end put a small half-

circle on top.

This will be a picture of a wine glass. Draw a triangle on top of an upside-down T.

This will be a picture of a crutch. Draw a tall thin triangle pointing down and put a bar in

the middle.

This will be a picture of a clock. Draw a circle and put an L in the upper right.

This will be a picture of an umbrella. Draw a short wide triangle and put a long J under-

neath.

This will be a picture of a kite. Draw a diamond and put a long curving line at the

bottom.

This will be a picture of a see-saw. Draw a small triangle and put a long horizontal line on

top.

This will be a picture of a swing. Draw a wide flat rectangle with two vertical lines

going up.

This will be a picture of a diamond ring. Draw a circle and just above it put a small triangle

pointing down.

This will be a picture of a candle. Draw a tall narrow rectangle and put an oval just

above the top.

This will be a picture of a teepee. Draw a triangle and put a V on top.

This will be a picture of a tent. Draw a triangle and lean a parallelogram against it.

This will be a picture of a spoon. Draw a long thin rectangle and put an oval at one end.

This will be a picture of a unicycle. Draw a circle and a tall T extending to the circle’s

center.

This will be a picture of a dumbell. Draw a horizontal line and put a circle at each end.

This will be a picture of a ladle. Draw and square and extend a vertical line out from

one top corner.

This will be a picture of a ladder. Draw two vertical lines and add four horizontal lines

between them.

This will be a picture of a bird’s head. Draw a small left-pointing triangle next to a circle with

a dot inside.

This will be a picture of a record. Draw two concentric circles and put a dot in the

center.

This will be a picture of a clothes dryer. Draw two concentric circles inside a large square.

This will be a picture of an ice-cube tray. Draw a tall rectangle with a vertical bar and three hori-

zontal bars.

This will be a picture of a wail with a mousehold in it. Draw a rectangle with a small half-circle just above

the bottom edge.

This will be a picture of a hat. Draw a horizontal line and put a half-circle on top.

This will be a picture of an eye. Draw a wide oval and put a circle in the middle.

This will be a picture of a padlock. Draw a large half-circle on top of a square.

PROCESSINGWRITTENDIRECTIONS 35

This will be a picture of a door. This will be a picture of a thermometer. Draw a rectangle and put a small circle near one side. Draw a tall thin rectangle and put a small circle at the

This will be a picture of a mushroom. Draw a half-circle and put a small square underneath.

This will be a picture of a wrist watch. Draw a circle and put a long rectangle on both sides.

This will be a picture of a coat rack. Draw a vertical line and put a V one-third of the way

down.

This will be a picture of an hourglass. Draw a tall rectangle and connect the corners with

straight lines.

This will be a picture of a pencil. Draw a long thin rectangle and put a triangle at one

end.

This will be a picture of an apple. Draw a circle and draw a short arc extending out from

the top.

This will be a picture of a light bulb. Draw a circle with a small square underneath and a Y

inside.

This will be a picture of a stopwatch. Draw a circle and put a small T on top.

This will be a picture of a car. Draw a rectangle with a square on top and two circles

underneath.

bottom.

This will be a picture of a safety pin. Draw a long oval and put a circle in each end.

This will be a picture of a ruler. Draw a long rectangle and put many vertical lines

along the top edge.

REFERENCES CARPENTER, P. A.. & DANEMAN, M. (1981). Lexical

retrieval and error recovery in reading: A model based on eye fixations. Journal of Verbal Learning and Verbal Behavior, 20, 137- 160.

DIXON, P. (1982). Plans and written directions for complex task. Journal of Verbal Learning and Verbal Behavior, 21, 70-84.

DIXON, P. tin press, a). The structure of mental plans for following directions. Journal of Experimenta/ Psychology: Learning. Memory, and Cognition.

DIXON, P. (in press, b). Actions and procedural directions. In R. Tomlin (Ed.), Coherence and grounding in discourse. Amsterdam: Benjamins.

GOLDMAN, S. R., HOGABOAM, T. W., BELL, L. C., & PERFET~I, C. A. (1980). Short-term retention of discourse during reading. Journal of Educa- tional Psychology, 72, 647-655.

JARVELLA. R. J. (1971). Syntactic processing of con- nected speech. Journal of Verbal Learning and

This will be a picture of a yield sign. Verbal Behavior, 10, 409-416.

Draw a triangle pointing down and put a vertical line JUST, M. A., & CARPENTER, P. A. (1980). A theory of

underneath. reading: From eye fixations to comprehension. Psychological Revieuj, 87, 329-354.

This will be a picture of a balloon. Draw a circle with a curving line underneath. (1960). Plans and the structure of behavior. New

MILLER, G. A., GALANTER, E., & PRIBRAM, K. H.

This will be a picture of a phone dial. York: Holt.

Draw a circle and put ten small circles just inside its PERFETTI, C. A. (1985). Reading ability. New York:

perimeter. Oxford Univ. Press.

This will be a picture of a flying saucer. PERFETTI, C. A., & GOLDMAN, S. R. (1976). Dis-

Draw a long thin oval and put a half-circle on top. course memory and reading comprehension skill. Journal of Verbal Learning and Verbal Behavior, 15, 33-42. This will be a picture of a coat hanger.

Draw a wide triangle and put a C on top.

This will be a picture of a keyhole. Draw a tall thin rectangle and put a small circle on top.

This will be a picture of a comb. Draw a long rectangle and put a series of right tri-

angles on top.

This will be a picture of a lollipop. Draw a circle and a vertical line underneath it.

SACERDOTI, E. D. (1977). A structure for plans and behavior. New York: ElsevieriNorth-Holland.

SMITH. E. E., &GOODMAN, L. (1984). Understanding instructions: The role of explanatory material. Cognition and Instruction. 1, 359-396.

THIBADEAU. R., JUST, M. A., & CARPENTER, P. A. (1982). A model of the time course and content of reading. Cognitive Science, 6, 157-203.

WILENSKY. R. (1983). Planning and understanding. Reading, MA: Addison-Wesley. This will be a picture of a hamburger.

Draw two wide ovals with a long thin oval in between.

This will be a picture of a factory. Draw a long rectangle and put a series of right tri- (Received December 30, 1985)

angles on top. (Revision received September 2. 1986)

the processing of organizational and component step information in written directions

Documents