The Role of Interest in Learning From Scientific Text and Illustrations ...

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Journal of Educational Psychology 1997,Vol. 89, No. 1,92-102

Copyright 1997 by (he American Psychological Association, Inc. 0022-0663/97/S3.00

The Role of Interest in Learning From Scientific Text and Illustrations: On the Distinction Between Emotional Interest and Cognitive Interest Shannon F. Harp and Richard E. Mayer University of California, Santa Barbara A textbook lesson may be made more interesting by promoting emotional interest through adding entertaining text and illustrations or by promoting cognitive interest through adding signals for structural understanding such as summary illustrations with captions. In Experiment 1, skilled readers who read summary text and illustrations about the process of lightning performed worse on retention of important information and on transfer when entertaining text, illustrations, or both were added. In Experiment 2, skilled readers rated entertaining text and illustrations relatively high in emotional interest and low in cognitive interest and rated summary illustrations and text relatively low in emotional interest and high in cognitive interest. The results suggest benefits of cognitive interest over emotional interest for helping students learn scientific explanations.

What can be done to make a scientific textbook lesson more interesting? For example, consider the following scenario. A high school textbook contains a six-paragraph lesson that explains the formation of lightning, such as shown in the Appendix. Students find the passage boring. When asked to explain how lightning is formed, the students perform poorly; when asked to solve problems based on the explanation, they also perform poorly. Instructional designers are called in to improve the interestingness of the lesson, in hopes of improving students' learning. One way to make the passage more interesting is to add entertaining details to each paragraph in the form of words or illustrations. The goal of this approach is to increase the reader's general level of arousal so that the reader will attend to more information from the passage. For example, we could add text within the final paragraph that concretely describes how a high school football player was struck by lightning during practice, or we could add a color illustration next to the final paragraph that shows a hole torn in a football player's helmet by a lightning bolt. The middle column of Figure 1 contains interesting sentences that could be added to each respective paragraph in the lightning passage, and the right column of Figure 1 contains interesting illustrations that could be placed to the right of each respective paragraph. Although these details about lightning may be interesting and entertaining, they are not directly relevant to the explanation of the cause-and-effect steps involved in the formation of lightning. Scholars have used the term seductive details to refer to interesting but irrelevant details that are added to a passage to make it more interesting (Garner, Brown, Sanders, & Menke, 1992; Garner, Gillingham, & White, 1989). To distinguish between the use of words and illustrations, we

use the term seductive text to refer to interesting but irrelevant text that is added to a passage, and we use the term seductive illustrations to refer to interesting but irrelevant illustrations that are added to a passage. We define interesting to mean that readers rate the material to be entertaining and interesting. We define irrelevant to mean that it is not related to a step in the cause-and-effect explanation, although it may be related to the general topic of the passage. An alternative way to increase student interest in the lightning passage is to add material that signals the structure of the explanation, that is, the cause-and-effect chain of events in the formation of lightning. For example, the lightning passage includes six major steps in the formation of lightning, with one step leading to the next. The left column of Figure 1 presents a series of six captioned illustrations that summarize the causal chain that could be placed to the left of the six text paragraphs, respectively. Although not as entertaining as the seductive text and seductive illustrations, the captioned illustrations are more relevant to the goal of understanding the cause-and-effect explanation because they summarize it with words from the text. In short, the captioned illustrations signal the most important steps required for forming a mental model of the lightning process. We use the term explanative summary to refer to an adjunct that summarizes the cause-and-effect chain of a process, such as exemplified in the left column of Figure 1. The goal of an explanative summary is to help the reader understand the structure of the causal explanation by helping him or her focus on the key steps and the causal relations among them. It follows that when readers understand the process of lightning formation that is explained in the passage, they also find the passage more interesting. The Case of Emotional Interest Versus Cognitive Interest

Correspondence concerning this article should be addressed to Shannon F. Harp or Richard E. Mayer, Department of Psychology, University of California, Santa Barbara, California 93106. Electronic mail may be sent via Internet to [email protected] or [email protected].

These two approaches for increasing the interestingness of a scientific explanation exemplify two alternative theo92

INTEREST IN LEARNING ries of the role of interest in learning from text and illustrations, which we derive from Kintsch's (1980) distinction between emotional interest and cognitive interest. The first approach, in which seductive text, seductive illustrations, or both are added to a scientific text, is based on emotional interest theory. According to emotional interest theory, the addition of interesting but irrelevant material to a textbook lesson energizes readers so that they pay more attention and learn more overall. Although the material is irrelevant to the explanation, it is related to the topic and intended to heighten the reader's curiosity and interest in the topic. According to emotional interest theory, emotional interest adjuncts, such as seductive text or seductive illustrations, influence the reader's affect by promoting his or her enjoyment of the passage. The increase in emotional arousal influences the reader's cognition; that is, the increase in enjoyment causes the reader to pay more attention to and encode more of the material in the passage. If emotional interest theory is correct, we can predict that adding emotional interest adjuncts to text will result in increases on tests of retention and transfer. The case of emotional interest is summarized in the left column of Table 1. In contrast, the second approach is based on cognitive interest theory. The premise underlying cognitive interest theory is that scientific passages become more interesting when readers understand them. Kintsch (1980, p. 89) summarized the role of cognitive interest in the following: "The text as a whole must hang together and make sense to the reader, so that he is able to construct a coherent macrostructure in which each text unit has a place and is meaningfully related to other sections of the text." This can be accomplished by adding material that signals the structural coherence of the explanation, such as an explanative summary that highlights the steps and relations in the cause-and-effect chain. According to cognitive interest theory, cognitive interest adjuncts such as explanative summaries influence the reader's cognition by promoting the reader's structural understanding of the explanation. In particular, cognitive interest adjuncts promote the reader's construction of a causal chain by helping readers focus their selective attention on relevant pieces of information (i.e., the steps in the process) and on helping readers build internal connections among the pieces of information (i.e., cause-and-effect relations). Then, this qualitative change in the kind of cognitive processing influences the reader's affect; that is, the attainment of structural understanding promotes a sense of positive affect about the passage. The cognitive consequences of adding explanative summaries have been explored in a series of studies (Mayer, 1989; Mayer, Bove, Bryman, Mars, & Tapangco, 1996; Mayer, Steinhoff, Bower, & Mars, 1995). Consistent with the predictions of cognitive interest theory, these studies yield consistent findings that students who read scientific texts with explanative summaries remember the explanation and solve problems involving the explanation better than do students who read texts without summaries. Therefore, the main focus of this article is on the cognitive consequences of adding emotional interest adjuncts such as seductive text and seductive illustrations.

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What happens when emotional interest adjuncts, such as seductive text and seductive illustrations, are incorporated into scientific passages? The rationale against using emotional interest adjuncts, such as seductive text and seductive illustrations, is that they disrupt the reader's construction of the cause-and-effect chain. In particular, emotional interest adjuncts distract the reader's selective attention away from relevant explanative information (i.e., steps in the causal chain) and interfere with the reader's building of connections among key steps in the causal chain. Therefore, on the basis of cognitive interest theory, we can predict that adding emotional interest adjuncts to text will result in decreases on tests of retention for the explanative information—because readers shift their attention from relevant to irrelevant information—and decreases on solutions to transfer problems that require readers to use their mental representations of the causal chain—because readers expend less effort in developing these representations. The case of cognitive interest is summarized in the right column of Table 1. Does Adding Seductive Text Improve Comprehension? Whether emotional interest adjuncts improve learning is a classic issue in educational psychology, dating back to Dewey's (1913) Interest and Effort in Education. Although Dewey (p. ix) recognized the central role of interest in learning, he warned against viewing interest as some sort of flavoring that can be sprinkled on an otherwise boring lesson: "When things have to be made interesting, it is because interest itself is wanting. Moreover, the phrase is a misnomer. The thing, the object, is no more interesting than it was before" (Dewey, 1913, pp. 11-12). Dewey's admonition is consistent with an important working hypothesis for modern research based on cognitive interest theory. It leads to a straightforward prediction, which can be called the seductive details hypothesis—adding interesting but irrelevant details to an otherwise boring text will interfere with the recall of important information. Overall, research on the seductive details hypothesis shows that adding interesting text that is irrelevant to the theme of a descriptive or narrative passage either reduces or does not facilitate students' remembering of the main ideas in the passage (Gamer et al., 1992; Garner et al., 1989; Hidi & Baird, 1988; Mohr, Glover, & Ronning, 1984; Shirey, 1992; Shirey & Reynolds, 1988; Wade, 1992; Wade & Adams, 1990). A related finding is that readers are more likely to remember interesting facts than structurally important facts from a text passage (Garner, Alexander, Gillingham, Kulikowich, & Brown, 1991; Garner et al., 1992; Hidi & Anderson, 1992; Hidi & Baird, 1986). Extensions of Research on the Seductive Details Hypothesis The present study extends this line of research on the seductive details hypothesis in three ways. First, we have used explanative text rather than descriptive or narrative

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Every year approximately 150 Americans are killed by lightning. Swimmers are sitting ducks for lightning, because water is an excellent conductor of this electrical discharge. Lightning results from the difference in electrical charges between cload n d ground.

Swimmers are aning ducks for lightning.

When flying through updrafts, an airplane ride can become bumpy. Metal airplanes conduct lightning very well, but they sustain little damage because the bolt, meeting no resistance, passes right through. Warm moist an rises, witer vtpor condenses n d forms a cloud.

Metal airplanes conduct booming but sustain link damase

When lightning strikes the ground, fulgurites may form, as the heat from the lightning fuses sand into the shape of the electricity's path. Lightning fuses sand into the shape of the electricity's pith. Raindrop* and ice crystals drag air downward.

In trying to understand these processes, scientists sometimes create lightning by launching tiny rockets into overhead clouds.

•

Scientists create lightning by launching liny rockets. Negatively charged particles M to bottom of cloud.

Golfers are prime targets of lightning strikes because they tend to stand in open grassy fields, or to huddle under trees. Golfers arc prime targets of lightning strikes. Two leaden meet, negatively charged particles rush from cloud to ground.

Approximately 10,000 Americans are injured by lightning every year. Eyewitnesses in Burtonsville, Maryland, watched as a bolt of lightning tore a hole in the helmet of a high school football player during practice. The bolt burned his jersey, and blew his shoes off. More than a year later, the young man still won't talk about his near death experience. Positively charged panicles from the ground rash upward along the same path.

A lightning boh tore a hole in the helmet of a football player, burned his jersey and blew bis shoes off

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Table 1 Characteristics of Emotional and Cognitive Interest Adjuncts for Scientific Texts Characteristic Definition of adjunct

Emotional interest adjunct Added material that is entertaining but irrelevant to explanation

Cognitive interest adjunct Added material that signals structural coherence of explanation (i.e., steps and relations in cause-and-effect chain)

Example of adjunct

Seductive text, seductive illustrations

Explanative summary

Consequence of adjunct

Adjunct influences affect: Seductive text/illustrations promote reader's enjoyment

Adjunct influences cognition: Explanative summary promotes reader's structural understanding (i.e., construction of causal chain) by focusing attention on relevant information and building connections

Mechanism

Affect influences cognition: Enjoyment promotes general attention

Cognition influences affect: Structural understanding promotes enjoyment

Theoretical rationale: Cognitive consequences of emotional interest adjuncts

Increase in general attention

Disrupt construction of causal chain by distracting selective attention from relevant explanative information and interfering with the construction of internal connections

Practical rationale: Predictions for emotional interest adjuncts

Increase in retention and transfer

Decrease in retention and transfer

text because of our recognition that explanation is at the heart of science (Mayer, 1992). The underlying rhetorical structure for passages containing scientific explanations can be called process (Cook & Mayer, 1988), in which a change in one part of a system leads to a change in another part, and so on. For example, the major causal events in the lightning passage are summarized in the captions on the left side of Figure 1. Second, we have added seductive illustrations as a new kind of seductive detail in recognition of the fact that illustrations are often used to decorate pages in scientific and mathematics text books (Levin & Mayer, 1993; Mayer, 1993; Mayer, Sims, & Tajika, 1995). Levin (1989) coined the term decorative illustrations to refer to illustrations that are interesting but serve no clear pedagogic purpose. One possible justification for devoting page space to decorative illustrations may be that they serve an affective or motivational purpose; that is, by increasing the reader's interest in the textbook lesson. Third, we have added problem-solving transfer as a new way of measuring what students learn from a scientific passage because our focus is on student understanding. Previous research has demonstrated that students who recall

information equally well may not be equally able to use that information to solve problems (Mayer, Steinhoff et al., 1995; Mayer et al., 1996).

Experiment 1 In Experiment 1, we mainly focused on the cognitive consequences of adding interesting but irrelevant information (i.e., seductive text, seductive illustrations, or both) to a scientific passage that explains how lightning forms (i.e., 550 words and 6 captioned illustrations). According to emotional interest theory, the added information will energize readers so that they pay more attention to the passage and therefore learn more overall. As a result, students who receive the passage with seductive text, seductive illustrations, or both should perform better on tests of overall retention of the material in the passage than students who receive the passage without the additional material. In contrast, according to cognitive interest theory, the added information will distract the reader from making sense out of the passage by diverting his or her attention away from the key explanative events and their cause-and-effect relation.

Figure 1. Three kinds of adjuncts for the lightning passage. The left column contains an explanative summary designed to promote cognitive interest; the middle column contains seductive text designed to promote emotional interest; and the right column contains seductive illustrations designed to promote emotional interest. For instructional booklets used in Experiments 1 and 2, each illustration was approximately 2.5 in. square and seductive illustrations were presented in color. Left column reprinted from "When Less Is More: Meaningful Learning From Visual and Verbal Summaries of Science Textbook Lessons," by R. E. Mayer, W. Bove, A. Bryman, R. Mars, & Lene Tapangco, Journal of Educational Psychology, 88, 64-73. Copyright 1996 by the American Psychological Association. Photographs adapted from "Lightning: Nature's High-Voltage Spectacle," by W. Newcott, 1993, National Geographic, 184, pp. 89, 90, 97, 98. Copyright 1993 by Peter Menzel. All rights reserved. Adapted by permission.

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As a result, students who receive the passage with seductive text, seductive illustrations, or both should perform more poorly on selective retention of the key explanative events and on problem-solving transfer that requires understanding. We selected students who were not highly knowledgeable about meteorology because previous research has shown that instructional manipulations have the greatest impact on low-knowledge learners (Mayer, in press; Mayer & Gallini, 1990).

Method Participants and design. The participants were 74 college students recruited from the Psychology Subject Pool at the University of California, Santa Barbara. All participants rated their knowledge of meteorology as low on a participant questionnaire (as described in the materials and apparatus section and in the scoring section). Each participant served in one cell of a 2 x 2 betweensubjects factorial design, with the first factor being the presence or absence of seductive text and the second factor being the presence or absence of seductive illustrations. There were 19 participants in the base group, 17 in the base-plus-seductive-text group, 18 in the base-plus-seductive-illustrations group, and 20 in the base-plusseductive-text-and-seductive-illustrations group. Materials and apparatus. The materials consisted of a participant questionnaire, four instructional booklets, an interest inventory, a recall sheet, and four problem-solving sheets, each typed on 8.5 X 11 in. (2.05 X 2.79 dm) sheets of paper and adapted from Mayer, Steinhoff et al., (1995). The apparatus consisted of a stopwatch that was used to time the participants. The participant questionnaire solicited demographic information, including age, gender, and Scholastic Aptitude Test (SAT) scores. It also requested the participants to rate their knowledge of weather by writing a check mark on a 5-point scale (ranging from very little to very much), and to write a check by each of six weather-related items that applied to them, including the following: (a) "I know what a cold front is," (b) "I can distinguish between cumulous and nimbus clouds," (c) "I know what a low pressure system is," (d) "I can explain what makes wind blow," (e) "I know what this symbol means" [symbol for warm front], and (f) "I know what this symbol means" [symbol for cold front]. Each of the instructional booklets consisted of a four-page passage pasted inside a folder such that only two facing pages were visible at a time, mimicking the format of a textbook. All pages were typed in black text on white sheets of paper, and the title, "The Process of Lightning," appeared above the text on the first page of each booklet in large, bold print. The base booklet consisted of approximately 550 words (as shown in the Appendix and 6 black-and-white captioned illustrations explaining the cause-and-effect steps in the formation of lightning (as shown in the left portion of Figure 1). Captions included approximately 60 words and were taken directly from the 550-word passage. The passage was broken down into six paragraphs, each describing a step in the process of lightning formation based on factual information found in high school science textbooks and encyclopedias. The first page contained two paragraphs, the second page contained two paragraphs, the third page contained one paragraph, and the fourth page contained one paragraph. To the left of each paragraph was a corresponding illustration depicting a step in the process of lightning; each illustration included a caption that briefly described the pictured event with words repeated from the paragraph. The base-plus-seductive-text booklet contained the same base

text and illustrations as the base booklet, along with the addition of 150 words intended to make the passage more interesting (which we refer to as seductive text). The middle column of Figure 1 lists the sentences that were incorporated into each paragraph to add one or two seductive details into each paragraph. The sentences containing the seductive details were careftilly chosen to flow within the base passage and were adapted from an article on lightning in the National Geographic (Newcott, 1993). The base-plus-seductive-illustrations booklet consisted of the base booklet, along with the addition of six captioned color photographs taken from a National Geographic article on lightning (Newcott, 1993), as shown in the right side of Figure 1. The captions included approximately 60 words taken directly from the seductive text described above. One photograph was placed to the right of each paragraph to which it was marginally related. The base-plus-seductive-text-and-seductive-illustrations booklet contained the base booklet along with the seductive text (i.e., 150 words shown in the middle column of Figure 1) and the seductive illustrations (i.e., 6 captioned, color photographs depicted in the right column of Figure 1). The interest inventory consisted of the following four questions designed to assess reader interest concerning the passage: (a) "While reading the passage I felt interested," (b) "While reading the passage I felt bored," (c) "I found the information in the passage to be useful," and (d) "I found the information in the passage to be worthless." The participants were asked to rate their level of agreement to each statement on a 4-point scale, ranging from completely to not at all. The recall sheet had the following instruction typed at the top of the page: "Please write down everything you can remember from the passage." The recall sheet had the following instruction typed at the bottom of the page: "Please keep working until instructed to stop." Each of the four problem-solving sheets had one of the following questions typed at the top of the page: (a) "Suppose you see clouds in the sky, but no lightning. Why not?" (b) "What could you do to decrease the intensity of a lightning storm?" (c) "What does air temperature have to do with lightning?" and (d) "What causes lightning?" At the bottom of each sheet was the following reminder: "Please keep working until instructed to stop." Procedure. Participants were tested in groups of 1 to 5 per session, with each participant seated in a separate cubicle. Participants were randomly assigned to a treatment group. First, participants filled out the participant questionnaire at their own rates. Second, participants were informed that they would be reading a four-page passage about the process of lightning, and that, after they had finished reading, they would be asked a series of questions about what they had read. They were instructed to read carefully at their normal reading rates, to read the passage one time only, and to close their booklets after reading through the passage one time. No time limit was imposed, and the experimenter was present at all times to ensure that the passage was read only once by eaeh participant. Then, each participant was given the booklet corresponding to his or her treatment group and told to start reading. Participants were not allowed to take notes or to mark on their booklets. Third, as each participant finished reading, the experimenter collected the booklet and handed the participant the interest inventory to fill out at his or her own rate. After all participants had filled out the interest inventory, they were given the recall sheet. Participants were told that they would have 6 min to write "everything you can remember from the passage" and that they need not be concerned about neatness or writing style. The experimenter collected the sheets after 6 min had passed.

INTEREST IN LEARNING Fourth, the participants were given the four problem-solving sheets, one sheet at a time, and were allowed 2.5 min to work on each sheet. As each sheet was given out, the experimenter instructed the participants to write down as many solutions to the problem as possible, and that they would have 2.5 min to answer the question. After they spent 2.5 min on one sheet, the experimenter collected it and handed out the next sheet, repeating the instructions. The order in which the problem-solving sheets were administered was counterbalanced to minimize order effects. After the final sheet had been collected, the participants were then thanked for their participation and dismissed.

Results and Discussion Scoring. The scoring procedures for the retention test, problem-solving test, and meteorological knowledge portion of the participant questionnaire were identical to those used in previous studies (Mayer, Steinhoff et al., 1995; Mayer et al., 1996). The recall test of each participant was scored by assigning 1 point for each of the following eight causal chain idea units, in any order and not necessarily in verbatim form, that appeared in the participant's written answer: (a) lightning can be defined as the difference in electrical charges between the cloud and the ground, (b) warm moist air rises, (c) water vapor condenses and forms a cloud, (d) raindrops and ice crystals drag air from the top of the cloud downward, (e) negatively charged particles fall to the bottom of the cloud, (f) two leaders meet, (g) negatively charged particles rush from the cloud to the ground, and (h) positively charged particles rush from the ground upward along the same path. For each participant, the total number of causal chain idea units was tallied, yielding a possible score ranging from 0 to 8. The problem-solving test of each participant was scored by assigning 1 point for each acceptable answer written by the participant across all four questions, yielding a possible score ranging from 0 to an unlimited number. To aid in scoring, a list of acceptable and unacceptable answers was generated for each question. For the question asking why there may be no lightning when there are clouds in the sky, acceptable answers included that the tops of the clouds may not be high enough to freeze, and that there may not be enough moisture in the air. For the question asking how the intensity of a lightning storm may be decreased, acceptable answers included removing positive ions from the ground and adding positive ions near the cloud. Acceptable answers for the question about air temperature included that the air must be cooler than the ground, and that the top of the cloud must be cooler than the bottom. For the question asking what causes lightning, acceptable answers included a difference in electrical charge in the cloud between the positively charged top and the negatively charged bottom and a difference in electrical charge between a negative charge in the cloud and positive charge on the ground. The interest survey was scored by assigning a value from 0 to 3 to the 4-point rating scale, with 0 indicating the least amount of interest and 3 indicating the most amount of interest. For each participant, the values were summed for the four items on the interest survey, yielding a possible score of 0 to 12.

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Each participant's knowledge of meteorology was scored by tallying the number of six weather-related items checked on the participant questionnaire and adding the participant's self-rating of weather knowledge (with 1 as very little to 5 as very high), yielding a possible score ranging from 0 to 11. Only students who obtained scores of 8 or less were included in the study because, on the basis of previous studies, we considered scores above 8 to indicate high knowledge of meteorology. Three students scored above 8. Data for these students were not included in the study, yielding a total sample of 74 participants. Issue I: Do students who read passages containing seductive text, seductive illustrations, or both recall more or fewer idea units on the retention test than do students who read base passages? According to emotional interest theory, the addition of seductive text, seductive illustrations, or both should energize readers so that they pay more attention and learn more overall. As a result, students in the base group should perform worse on the retention test than do students in the other three groups. In contrast, according to cognitive interest theory, the addition of seductive text or illustrations should disrupt text cohesiveness and therefore distract readers from paying attention to relevant information and constructing a cause-and-effect model of the steps in the formation of lightning. As a result, students in the base group should perform better on the retention test than do students in the other three groups. The left panel of Figure 2 presents the mean number of steps in the causal chain recalled on the retention test (out of a total possible of 8). As can be seen, students in the base group recalled the most, whereas students who read passages containing the base along with seductive text and illustrations recalled the least. A one-way analysis of variance (ANOVA) indicated that there was a significant difference among the four groups, F(3, 70) = 14.60, MSE = 1.93, p < .001. A supplemental Tukey's honestly significant difference (HSD) test (with alpha less than .05) revealed that the base group recalled significantly more relevant idea units than did the other three groups, and the base-plus-seductive-text-and-seductive-illustrations group recalled significantly fewer relevant idea units than did the other groups. This pattern of results is consistent with the predictions of cognitive interest theory and inconsistent with the predictions of emotional interest theory. Issue 2: Do students who read passages containing seductive text, seductive illustrations, or both generate more or fewer creative solutions on the transfer test than do students who read base passages? According to emotional interest theory, the addition of seductive text, seductive illustrations, or both should energize readers so that they pay more attention and learn more overall. As a result, students in the base group should perform worse on the transfer test than do students in the other three groups. In contrast, according to cognitive interest theory, the addition of seductive text or illustrations should distract readers from selecting relevant information from the passage and constructing a cause-and-effect model of the steps in the formation of lightning. As a result, students in the base group

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should perform better on the transfer test than do students in the other three groups. The middle panel of Figure 2 presents the mean number of creative solutions generated on solving the four problems on the transfer test. As can be seen, students who read the base passage generated more solutions than did students in the other groups, and students who read passages containing both seductive text and seductive illustrations generated the fewest number of creative solutions. A one-way ANOVA revealed that the four means differed significantly from one another, F(3, 70) = 6.71, MSE = 1.93, p < .001. A supplemental Tukey's HSD test (with alpha less than .05) revealed that the base group performed significantly better than the base-plus-seductive-text group and the base-plusseductive-text-and-seductive-illustrations group; although there was a trend for the base-plus-seductive-illustrations group to perform more poorly than the base group, the difference failed to reach significance. Issue 3: Do students who read passages containing seductive text, seductive illustrations, or both rate the passage as more or less interesting than do students who read base passages? The foregoing results are inconsistent with emotional interest theory and are consistent with cognitive interest theory. However, a supplementary issue examined in Experiment 1 concerns the degree to which the students found the passages to be interesting. According to emotional interest theory, students should rate the passage as more interesting when seductive text, seductive illustrations, or both are added to the base passage than when the base passage is presented alone. In making this prediction about emotional interest theory, we assume that students

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base their interest ratings on how entertaining the passage was. In contrast, according to cognitive interest theory, if students base their ratings of interest on how well they understood the explanation (i.e., on their satisfaction from making sense of the passage), then the opposite pattern of results should be obtained. In particular, students should rate the base passage as interesting because its conciseness allows students to understand the steps in the causal chain, whereas students may rate the other versions of the passage as less interesting because they make it more difficult for students to build the causal chain. The right panel of Figure 2 shows the mean interest score for each of the four versions of the passage. As can be seen, the mean ratings are somewhat similar, such that the passage with both kinds of seductive adjuncts (base-plusseductive-text-and-seductive-illustrations booklet) was rated as no more interesting than the passage containing no seductive adjuncts (base booklet). An ANOVA revealed that there were no significant differences among the mean interest ratings for the four booklets, F(3, 70) < 1, MSE = 5.84, p = ns. The failure to find differences in students' ratings of interestingness among the four booklets raises the possibility that our interest inventory did not allow for the distinction between emotional interest and cognitive interest. Students who read the passages containing seductive text, seductive illustrations, or both may have rated the passages as fairly interesting on the basis of the passages' high levels of emotional interest; that is, based on their evaluation of how entertaining the adjunct material was. In contrast, students who read the base passage may have rated it as

| Base IJU Base-plus-seductive-text

pl^ Base-plus-seductive-illustrations I Base-plus-seductive-text-and-seductive-illustrations Recall of explanation

Problem solving

SS 4 'S 3

."S ^ O

2

!

c

11

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Figure 2. Mean number of explanative idea units recalled, mean number of correct solutions generated, and mean interestingness ratings by four treatment groups in Experiment 1. The means (and standard deviations) on recall for the base, base-plus-seductive-text, base-plus-seductiveillustrations, and base-plus-seductive-text-and-seductive-illustrations groups were, respectively, 3.8 (1.6), 2.3 (1.3), 2.2 (1.7), and .9 (.8); the corresponding scores for problem solving were 3.2 (1.8), 1.6 (1.2), 2.1 (1.2), 1.2 (1.2); and the corresponding scores for interest rating were 7.3 (2.8), 8.2 (1.7), 8.1 (2.2), and 7.1 (2.8).

INTEREST IN LEARNING

interesting based on the passage's high level of cognitive interest; that is, on the basis of how well they understood the cause-and-effect explanation. To untangle these issues, a second study was conducted.

Experiment 2 To better examine students' interpretations concerning how to rate a passage's interestingness, we designed a new interest survey in Experiment 2 that asked students to give separate ratings for emotional interest (e.g., "How entertaining is this material?") and for cognitive interest (e.g., "How much does this material help you to understand the process of lightning?")- To control for which portion of the passage the students used as the basis for ratings, we asked students in Experiment 2 to read the base-plus-seductive-text-andseductive-illustrations passage and to provide separate ratings for the base text, captioned illustrations, seductive text, and seductive illustrations. If the distinction between emotional and cognitive interest is salient, then we predict that skilled readers will rate the seductive text and seductive illustrations relatively high on emotional interest and low on cognitive interest, whereas they will rate summary text and illustrations relatively low on emotional interest and high on cognitive interest. Overall, Experiment 2 provides additional evidence concerning the distinction between emotional and cognitive interest by examining the degree to which skilled readers can discriminate between text adjuncts that contribute to emotional interest and text adjuncts that contribute to cognitive interest.

Method Participants and design. The participants were 85 college students recruited from the same population as in Experiment 1. All students rated the same four portions of text (base text, summary captioned illustrations, seductive text, and seductive illustrations) on the same questions (emotional interest and cognitive interest) so that all comparisons are within subject. Materials. The materials consisted of (a) a participant questionnaire that was identical to the one used in Experiment 1, (b) a standard booklet containing a textbook passage on how lightning works that was identical to the base-plus-seductive-text-andseductive-illusrrations booklet used in Experiment 1, (c) a highlighted booklet containing the same passage with the seductive text highlighted in yellow, the seductive illustrations and captions highlighted in orange, the explanative illustrations and captions highlighted in green, and the base text not highlighted, and (d) four interest survey sheets. Each interest survey sheet was an 8.5 X 11 in. (2.05 X 2.79 dm) sheet of paper that contained a series of six questions, each followed by a 10-point scale. It contained two questions aimed at assessing emotional interest ("How interesting is this material?" with 1 as boring and 10 as interesting, and "How entertaining is this material?" with 1 as tiresome and 10 as entertaining) and two questions aimed at assessing cognitive interest ("How much does this material help you to understand the process of lightning?" with 1 as not at all and 10 as very much, and "How helpful is this material for organizing the steps involved in the process of lightning?" with 1 as unhelpful and 10 as helpful).1 The instructions at the top of the four sheets asked the participant to

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base ratings on the yellow, orange, green, or unmarked portions of the highlighted booklet, respectively. Procedure. Participants were tested in groups of 1 to 5 per session, with each participant seated in a separate cubicle. First, each participant completed the participant questionnaire. Second, the experimenter distributed the standard booklet, and, following brief directions, participants were given 6.5 min to read the textbook passage. Third, after 6.5 min had elapsed, the experimenter collected the passage, distributed the highlighted booklet, distributed a rating sheet, and provided instructions. Participants were told to base their ratings on the green portion of the text and to ignore everything else. They were told "for each question, please place a circle around the number that reflects your rating." Participants were given 2 min to rate the questions on the rating sheet. This procedure was repeated for the orange, yellow, and unmarked portions of the text, respectively, with order of testing fully counterbalanced between participants. Then, participants were thanked and excused.

Results and Discussion The main purpose of Experiment 2 was to determine whether skilled readers were sensitive to the distinction between emotional and cognitive interest. In particular, we predicted that the participants would rate the seductive text and seductive illustrations higher in emotional interest and lower in cognitive interest, whereas they would rate the base text and explanative illustrations as lower in emotional interest and higher in cognitive interest. For each participant, we computed the mean rating for the two emotional interest questions and the mean rating for the two cognitive interest ratings for each of the four sections of the passage. Figure 3 shows the average rating from 1 (lowest) to 10 (highest) for the two emotional interest questions and the two cognitive interest questions for each of the four sections of the passage. As predicted, seductive text was rated relatively high in emotional interest (M = 7.2, SD = 2.0) but relatively low in cognitive interest (M = 3.1, SD = 2.0), /(84) = 12.17, p < .001; similarly, seductive illustrations were rated high in emotional interest (M — 8.0, SD =1.8) but low in cognitive interest (M = 2.6, SD = 1.7), r(84) = 20.54, p < .001. Also, as predicted, summary captioned illustrations were rated relatively low in emotional interest (M - 4.5, SD = 2.0) but high in cognitive interest (M = 8.4, SD = 1.4), f(84) = 18.77, p < .001; similarly, the base text was rated relatively low in emotional interest (M = 4.6, SD = 2.1) but high in cognitive interest (M = 8.2, SD = 1.7), f(84) = 15.39, p< .001. These results are consistent with the claim that skilled readers can discriminate between portions of a textbook 1 In addition, the survey contained two questions concerning the importance of the information ("How important is this material for explaining how lightning works?" with 1 as unimportant and 10 as important, and "How necessary is this material for explaining the process of lightning?" with 1 as unnecessary and 10 as necessary). The mean ratings on these questions corresponded closely with those given for the cognitive interest questions: Ms = 3.3, 3.0, 8.3, and 8.6 for seductive text, seductive illustrations, explanative illustrations, and core text, respectively. These data were excluded from the analyses reported in this article.

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lesson that contribute to emotional interest and those portions that contribute to cognitive interest. In this way, the finding supports the validity of the distinction between emotional and cognitive interest for explanative lessons. Conclusion In the case of emotional interest versus cognitive interest, the verdict of this study is clear. Adjuncts aimed at increasing emotional interest failed to improve understanding of scientific explanations. We hypothesize that they interfered with student learning by distracting the reader's attention away from relevant events in the explanative chain and by disrupting the construction of causal links among events in the causal chain. Combined with previous research on explanative summaries (Dempster, 1993; Mayer, Steinhoff et al., 1995), the current findings show that the best way to help students enjoy a passage is to help them understand it. Paralleling our rejection of emotional interest in favor of cognitive interest, Hidi and Baird (1986, p. 191) concluded that "thinking of interest as a general arousal experience is inadequate" and should be replaced with "the idea of interest as a process responding to the significance of the information." Consistent with previous studies and with the predictions of cognitive interest theory, we found in Experiment 1 that adding seductive details hurt student learning of a scientific explanation. This finding extends previous research on the seductive details hypothesis in three important ways: (a) by including new independent variables, that is, by showing that seductive illustrations have the same deleterious effects as seductive text, (b) new text genres, that is, by showing that the seductive details effect occurs for explanative passages as well as for descriptive and narrative passages, and (c) new dependent measures, that is, by showing that the seductive details effect occurs for measures of understanding—such as problem-solving transfer—as well as for measures of retention—such as recall of the main idea units. Further, in Experiment 2, we found that skilled readers

I 10

Emotional interest

^ H Cognitive interest

"I

possess the metacognitive skills needed to distinguish between portions of a scientific passage that promote cognitive interest (i.e., explanative summaries) and those that promote emotional interest (i.e., seductive text and seductive illustrations). This finding strengthens our theoretical argument that emotional interest adjuncts and cognitive interest adjuncts have different effects on readers' cognitive processes while they are reading scientific text. A practical implication worthy of further study is that inexperienced readers may need practice in learning to identify portions of a textbook lesson that promote emotional interest and those that promote cognitive interest. In summary, this research points to the theoretical and practical benefits of the empirical study of interest in learning. On the theoretical level, this study provides important evidence in favor of cognitive interest theory over emotional interest theory based on the case of learning a scientific explanation. Chi a practical level, this study calls into question the overuse in science textbooks of attentiongrabbing color photographs that are not directly relevant to helping the reader make sense out the explanation in the passage. These conclusions must be tempered because a major limitation of this study is that it focuses on a single text, namely, an explanation of the formation of lightning. Subsequent research is needed to determine whether the same pattern of findings would occur for other explanative lessons. In addition, these conclusions should not be taken to controvert the value of illustrations in scientific text. To the contrary, our research has consistently shown how carefully crafted illustrations—such as a series of captioned, explanative illustrations—can contribute to the improvement of student performance on tests of retention and transfer (Mayer, 1989; Mayer, in press; Mayer & Gallini, 1990; Mayer, Steinhoff et al., 1995; Mayer et al., 1996). What this study has shown is that certain kinds of illustrations—such as a series of full pictures of interesting but irrelevant objects or scenes—can disrupt the cognitive processing needed for meaningful learning. Finally, this study reflects a growing resurgence of interest research. More than 80 years ago, Dewey (1913) challenged educational researchers to answer questions about the role of interest in learning. After decades of neglect, questions about the role of interest are making a comeback (Mayer, 1995; Renninger, Hidi, & Krapp, 1992). Research on interest represents an important venue for examining the relation between cognition and affect, thus broadening cognitive approaches to education. References

Base text

Explanative illustrations

Seductive text

Seductive illustrations

Figure 3. Mean emotional interest rating and cognitive interest rating on four portions of a scientific text in Experiment 2.

Cook, L. B., & Mayer, R. E. (1988). Teaching readers about the structure of scientific text. Journal of Educational Psychology, 80, 448-456. Dempster, F. N. (1993). Exposing our students to less should help them learn more. Phi Delta Kappan, 74, 432-437. Dewey, J. (1913). Interest and effort in education. Cambridge, MA: Houghton Mifflin. Garner, R., Alexander, P., Gillingham, M., Kulikowich, J., &

INTEREST IN LEARNING Brown, R. (1991). Interest and learning from text. American Educational Research Journal, 28, 643—659. Garner, R., Brown, R., Sanders, S., & Menke, D. (1992). "Seductive details" and learning from text. In K. A. Renninger, S. Hidi, & A. Krapp (Eds.), The role of interest in learning and development (pp. 239-254). Hillsdale, NJ: Erlbaum. Garner, R., Gillingham, M., & White, C. (1989). Effects of "seductive details" on macroprocessing and microprocessing in adults and children. Cognition and Instruction, 6, 41-57. Hidi, S., & Anderson, V. (1992). Situational interest and its impact on reading expository writing. In K. A. Renninger, S. Hidi, & A. Krapp (Eds.), The role of interest in learning and development (pp. 215-238). Hillsdale, NJ: Erlbaum. Hidi, S., & Baird, W. (1986). Interestingness: A neglected variable in discourse processing. Cognitive Science, 10, 179-194. Hidi, S., & Baird, W. (1988). Strategies for increasing text-based interest and students' recall of expository text. Reading Research Quarterly, 23, 465-483. Kintsch, W. (1980). Learning from text, levels of comprehension, or: Why anyone would read a story anyway. Poetics, 9, 87-98. Levin, J. R. (1989). A transfer-appropriate-processing perspective of pictures in prose. In H. Mandl & J. R. Levin (Eds.), Knowledge acquisition from text and pictures (pp. 83-100). Amsterdam: Elsevier. Levin, J. R., & Mayer, R. E. (1993). Understanding illustrations in text. In B. Britton, A. Woodward, & M. Binkley (Eds.), Learning from textbooks (pp. 95-113). Hillsdale, NJ: Erlbaum. Mayer, R. E. (1989). Systematic thinking fostered by illustrations in scientific text. Journal of Educational Psychology, 81, 240-246. Mayer, R. E. (1992). Knowledge and thought: Mental models that support scientific reasoning. In R. A. Duschl & R. J. Hamilton (Eds.), Philosophy of science, cognitive psychology, and educational theory and practice (pp. 226-243). Albany, NY: SUNY Press. Mayer, R. E. (1993). Illustrations that instruct. In R. Glaser (Ed.), Advances in instructional psychology. (Vol. 5, pp. 253-284). Hillsdale, NJ: Erlbaum. Mayer, R. E. (1995). How does interest affect learning? The return

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of a neglected question. [Review of The Role of Interest in Learning and Development]. American Journal of Psychology, 107, 319-323. Mayer, R. E. (hi press). Multimedia learning: Are we asking the right questions? Educational Psychologist. Mayer, R. E., Bove, W., Bryman, A., Mars, R., & Tapangco, L. (1996). When less is more: Meaningful learning from visual and verbal summaries of textbook lessons. Journal of Educational Psychology, 88, 64-73. Mayer, R. E., & Gallini, J. K. (1990). When is an illustration worth ten thousand words? Journal of Educational Psychology, 82, 715-726. Mayer, R. E., Sims, V., & Tajika, H. (1995). A comparison of how textbooks teach mathematical problem solving in Japan and the United States. American Educational Research Journal, 32, 443-460. Mayer, R. E., Steinhoff, K., Bower, G., & Mars, R. (1995). A generative theory of textbook design: Using illustrations to foster meaningful learning of science text. Educational Technology Research and Development, 43, 31-43. Mohr, P., Glover, J., & Ronning, R. R. (1984). The effect of related and unrelated details on the recall of major ideas in prose. Journal of Reading Behavior, 16, 97-109. Newcott, W. (1993). Lightning: Nature's high-voltage spectacle. National Geographic, 184, (1), 80-103. Renninger, K. A., Hidi, S., & Krapp, A. (1992). The role of interest in learning and development. Hillsdale, NJ: Erlbaum. Shirey, L. (1992). Importance, interest, and selective attention. In K. A. Renninger, S. Hidi, & A. Krapp (Eds.), The role of interest in learning and development (pp. 281-296). Hillsdale, NJ: Erlbaum. Shirey, L., & Reynolds, R. (1988). Effect of interest on attention and learning. Journal of Educational Psychology, 80, 159-166. Wade, S. (1992). How interest affects learning from text. In K. A. Renninger, S. Hidi, & A. Krapp (Eds.), The role of interest in learning and development (pp. 255-277). Hillsdale, NJ: Erlbaum. Wade, S., & Adams, R. (1990). Effects of importance and interest on recall of biographical text. Journal of Reading Behavior, 22, 331-353.

(Appendix follows on next page)

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Appendix Base Text The Process of Lightning Lightning can be defined as the discharge of electricity resulting from the difference in electrical charges between the cloud and the ground. When the surface of the earth is warm, moist air near the earth's surface becomes heated and rises rapidly, producing an updraft. As the air in these updrafts cools, water vapor condenses into water droplets and forms a cloud. The cloud's top extends above the freezing level. At this altitude, the air temperature is well below freezing, so the upper portion of the cloud is composed of tiny ice crystals. Eventually, the water droplets and ice crystals in the cloud become too large to be suspended by updrafts. As raindrops and ice crystals fall through the cloud, they drag some of the air from the cloud downward, producing downdrafts. The rising and falling air currents within the cloud may cause hailstones to form. When downdrafts strike the ground, they spread out in all directions, producing gusts of cool wind people feel just before the start of the rain. Within the cloud, the moving air causes electrical charges to build, although scientists do not fully understand how it occurs. Most believe that the charge results from the collision of the cloud's light, rising water droplets and tiny pieces of ice against hail and other heavier, falling particles. The negatively charged particles fall to the bottom of the cloud, and most of the positively charged particles rise to the top. The first stroke of a cloud-to-ground lightning flash is started by a stepped leader. Many scientists believe that it is triggered by a

spark between the areas of positive and negative charges within the cloud. A stepped leader moves downward in a series of steps, each of which is about 50 yards long, and lasts for about 1 millionth of a second. It pauses between steps for about 50 millionths of a second. As the stepped leader nears the ground, positively charged upward-moving leaders travel up from such objects as trees and buildings, to meet the negative charges. Usually, the upward moving leader from the tallest object is the first to meet the stepped leader and complete a path between the cloud and earth. The two leaders generally meet about 165 feet above the ground. Negatively charged particles then rush from the cloud to the ground along the path created by the leaders. It is not very bright and usually has many branches. As the stepped leader nears the ground, it induces an opposite charge, so positively charged particles from the ground rush upward along the same path. This upward motion of the current is the return stroke and it reaches the cloud in about 70 microseconds. The return stroke produces the bright light that people notice in a flash of lightning, but the current moves so quickly that its upward motion cannot be perceived. The lightning flash usually consists of an electrical potential of hundreds of millions of volts. The air along the lightning channel is heated briefly to a very high temperature. Such intense heating causes the air to expand explosively, producing a sound wave we call thunder.

Received February 27, 1996 Revision received May 21, 1996 Accepted May 21, 1996 •