Developmental Issues in Readability

I have worked with two pairs of students on two developmental projects.

One investigated the influence of illustrations on children's comprehension of and preference for storybooks. It is published in Reading Psychology.

The second tested children's ability to discriminate and identify letters in pairs as a function of size and font. It is now published in the online American Journal of Psychological Research.

Both are discussed further below.

I. The Influence of Illustrations in Children's Storybooks
(Presented at AERA 2002; the full paper is available: Reading Psychology, Vol 23(4), 323-339.)

Researchers: Jamye Andrews, Lauren Scharff, Laurie Moses

Most children's books contain illustrations, however, there has been little research on their effects, and even less (none that we could find) on the preferences of children with respect to different types of illustrations. Books geared to artists of children's books contain the subjective opinion of the adult authors about what are"good" illustrations, but contain no data regarding the children's preferences. Adults often choose books for children (sometimes with input from the children, but, especially for younger children, it is an adult choice), so the number of sales of a book may mostly reflect adult preferences.

Why would illustration preference be important? Common sense, as well as a few theories (e.g. the "motivation theory" proposed by Glenberg and Langston, 1992), suggest that illustrations may make a book more appealing and, thus, better engage the reader. The dual-code theory/repetition hypothesis proposes that information that is presented twice will enhance comprehension and memory (Gyselinckand Tardieu, 1999). Another theory suggests that pictures lure children to read and interact with the text and provide mental images, allowing them to understand the written text more easily and remember it longer (Fang, 1996). Illustrations may also increase thec omprehension and retention of the text material (Read and Barnsley,1977; Schallert, 1990).

Other theories suggest that illustrations can impair the reader's comprehension and recall of information (Elster and Simons, 1985). These theorists believe that pictures should only be used as a supplement to reading and they shouldn't be required for complete text comprehension. Another theory proposes that pictures hinder comprehension when the pictures contradict the text (Beck, 1984). There are several other theories regarding the influence of illustrations on reading for different levels of readers; however, most are just theories without data to support them.

Therefore, the purpose of our study was to obtain empirical data to determine the relationship between illustrations and reading comprehension. We also wanted to get a better idea about the specific styles of illustrations that children prefer.

We conducted a pilot study (July 2000; SFA charter school) to gather some general preference information from K-3 level school children. We gathered subjective data: preferences for eight books with illustrations. Our most significant finding was that the children tended to like illustrations in books that depicted brightly-colored, cartoon-like characters. While this is informative regarding general preferences, it does not provide information about the influence of illustrations on reading and content comprehensionas put forth in some theories. Further, it became apparent that the children's familiarity with the books influenced their reported illustration preferences, so it was not possible to conclude that the results were solely due to the different illustrations.

Thus, for the main experiment this past autumn, we created a newstory with four versions of illustrations, and we gathered both preference and empirical data (comprehension scores). The illustration versions included the following: bright-realistic, bright-abstract, somber-realistic, and somber-abstract. (View two example pictures for each style.) Realistic pictures resembled photographs while abstract pictures appeared more cartoon-like, although they were still not very abstract. All pictures had the same color scheme, so the abstract pictures only differed in the preciseness and detail of the drawing. In order to test the influenceof illustrations on comprehension, there were three groups of books: text plus illustrations, text only, and illustrations only. The comprehension questions came from one of three sources: information that was redundantly portrayed in the text and illustrations, information that was only in the text, and information that was only in the illustrations. Each participant only read one of the booktypes, but received all three types of questions.

We collected data from 36 first and 35 third graders from local schools in the Nacogdoches area. Participants were not selected based on reading level; six of the third graders were English-as-second-language students. For the book versions with text, participants in the third grade read the story, while participants inthe first grade had the story read to them. For the illustrations-only version, the participants were given the names of the characters and then made up a story to go with the pictures. After "reading" the story, participants answered the comprehension questions, and then gave us subjective feedback about their preferences regarding the illustrations. For the preference part ofthe study, participants were shown samples of all illustration styles.

We hypothesized that books with both text and illustrations would lead to better comprehension than text or illustrations alone. We also believed that brighter and abstract illustrations would be preferred (as we found in our pilot study), and better engage the reader, thus leading to better comprehension. Finally, we hypothesized that third graders would have better comprehension than first graders.

The results of our study indicate that the participants most strongly preferred the bright-realistic combination (c2 (3, N = 71) =48.61, p < .01). The participants especially liked bright pictures better than somber pictures (c2 (1, N=71) = 45.76, p < .01).

To test for the effects of illustrations on comprehension ananalysis of variance was performed. There were significant main effects for all variables, as well as a significant interaction between question type and book content. More specifically, third grade students did show better overall comprehension than did the first grade students (F (1, 53) = 4.08; p < .05). Overall, the text-plus-illustration books led to significantly better comprehension than did the illustration-only books, while there was no significant difference with the text-only books (F (8, 53) = 3.02;p < .01). For the two book types with illustrations (illustrations-only and text-plus-illustrations), there were no significant differences in comprehension between the different styles of illustration (i.e. the bright, somber, realistic, abstract combinations), although there were trends. The text-plus-illustration questions led to better comprehension scores than did the text-only questions, than did the illustration-only questions (F (2, 53) =63.66; p < .01). The interaction between book type and question type (F (16, 106) = 5.89; p < .01), however, shows that the majority of the decrease in the scores for the text-only questions was due to those individuals who received the illustrations-only book. Finally, children reading the different book types showed no significant differences in comprehension when asked the text-plus-illustrations questions. There were no interactions between grade and the other variables.

The above results suggest that there are developmental differences in comprehension, but that the influence of illustrations is similar between first and third grade students. Further, illustrations do seem to influence comprehension and children's preferences for books in general. More specifically, the group that "read" the illustration-only version did nearly as well (non-significant difference) as the other groups on the questions that contained information that was redundantly portrayed in both the text and illustrations. This suggests that pictures can serve as an aid to comprehension, and they may help beginning readers to comprehend the story and learn new words based on the pictures. The group reading the version with both text and illustrations showed a benefit (non-significant) over the text-only group for the text-plus-illustrations questions, but only if they liked the illustrations. This suggests that, if the illustrations are thoroughly processed, the redundancy may increase comprehension and long term memory for the items.

There was a potential downside to the pictures, however. If the illustrations were liked, there was a non-significant trend for the text-only questions to be answered slightly less accurately than when there were no illustrations at all. Because they may contain more attention-capturing information, pictures may act as a distraction. This supports Elster and Simons (1985) theory about the negative potential of illustrations.

In response to Beck's (1984) concern, however, we did have some data that suggest that contradictory pictures are not always detrimental to comprehension. The last page of the story had a contradiction between the text and the illustration. The text indicated the dog won the race, while the illustration showed the girl winning the race. The majority of the participants (84%) who received the text-plus-illustrations version of the book answered the question of who won the race based on the content from the text rather than the illustration. This comprehension result suggests that, when given both text and illustrations, the children more heavily rely on the text information when answering comprehension questions.

In sum, our data suggest that the addition of illustrations has greater benefits than detriments, and they validate the theories that propose benefits for illustrated text. Illustrations can attract readers to the book, and they can enhance the comprehension of the book material. Further, our data suggest that illustrations may serve as an aid when children are reading a new story. The value of our results may be extended to teachers and publishers. Teachers should be sensitive to children's responses to illustrated books, since illustrations can influence a child's motivation to approach a book and, in turn, the child's resultant comprehension of the book. Publishers may want to create focus groups to determine children's responses to proposed illustrations in new textbooks.

If this work is presented in a paper session, we would briefly outline the rationale, show example images from the books (each entire book would be available to view following the formal presentation), walk people through graphical representations of the results, and discuss implications of the results. We look forward to the group critique and discussion times to receive feedback and share ideas. This format would facilitate discussion across hopefully similar papers in the session, versus a poster session where there may be less across-projects discussion.


Elster, C., & Simons, H.D. (1985, November). How important are illustrations in children's readers? The Reading Teacher, 148-152.

Fang, Z. (1996). Illustrations, text, and the child reader: what are pictures in children's storybooks for? Reading Horizons, 37,130-142.

Glenberg, A.M., & Langston, W.E. (1992). Comprehension of illustrated text: pictures help to build mental models. Journal of Memory and Language, 31, 129-151.

Gyselinck, V., & Tardieu, H. (1999). The role of illustrationsin text comprehension: what, when, for whom, and why? In H. vanOostendorp & S.R. Goldman (Eds.), The construction of mental representations during reading (pp. 195-218). Mahwah, NJ: Lawrence Erlbaum.

Read, J.D., & Barnsley, R.H. (1977). Remember Dick and Jane? Memory for elementary school readers. Canadian Journal of Behavioral Science, 9, 361-370.

Schallert, D.L. (1980). The role of illustrations in reading comprehension. In R. J. Spiro, B.C. Bruce, & W.F. Brewer (Eds.), Theoretical issues in comprehension instruction (pp. 503-525). Hillsdale, NJ: Lawrence Erlbaum.


II. Effects of Typeface and Font Size on Legibility for Children
(Originally presented at SWPA 2001) (
Full paper in AJPR)

By Kristi Davis, Rebecca Woods, and Lauren Scharff
Stephen F. Austin State University

Problem: Much research has been dedicated to legibility andr eadability for adults. It is important to examine children as a specific population due to the effects that developmental changes and familiarity with characters may have on the readability of text. Research supports that children process letter information more slowly than adults (Krueger, 1973), but they are able to discriminate small visual details (Gaines, 1969), which suggests that differences in text such as typeface and size may also be discriminated. However, the discriminability may vary, and thus, these types of differences may influence the ease with which children are able read. Because a majority of children's reading material is found in printed form, it is important to examine readability of printed text for children. Although the publishing companies do have guidelines, they are generally not based upon empirical data (e.g. CTB/McGraw-Hill, L.Gerbrandt, personal communication, May 2000). The current research was an exploratory effort to determine how font variables might influence letter discriminability and legibility. Method: Two typefaces, Times New Roman (Serif) and Arial (San Serif), and two type-sizes, 12 point and 18 point were presented to children in grades K through 4 (N = 80). There were 24 trials per condition, leading to a total of 96 trials. Participants were instructed to report whether letter pairs presented using a tachistoscopic slide projector were the same or different (discrimination) and write the letters they saw (identification, a measure of legibility). Presentation time for each letter pair was 0.2 seconds. Visual angle of the presented letters was calculated to match that for an average reading distance of 18 inches. Total time to complete all trials varied by grade (20 minutes - 1.25 hours). Results: A four-factor mixed ANOVA, with grade as the between variable and typeface, size, and task as the within variables showed significant main effects for all variables, as well as a significant interaction between grade and task. Kindergarteners showed the worst performance on all conditions, and were the only group to show a significant decrease in performance from discrimination to identification. Overall, Arial was discriminated and identified better than Times New Roman, and the same pattern was seen for 18 point versus 12 point. These effects were more exaggerated for the Kindergarteners, although the interactions were not significant. Conclusion: Results support previous research on adults that show legibility increases with point size (Loomis, 1990; Smith, 1979). Currently, larger fontsizes (up to 24 point) are used for grades K-2 to compensate for challenges associated with early readers (e.g. CTB/McGraw-Hill). However, our results indicate that only Kindergartners show significantly poorer performance when using 18 or 12 point fonts, although first graders also showed some detriments when compared to the older children. Overall, the data suggest that as early as 2nd grade a 12 point font is adequately legible. Analysis of typeface shows that Arial is to be preferred over Times New Roman, which does not support the current use of serif fonts for reading material.

Return to Scharff Research Summary page.