Students often need to read and understand a lot of information by extracting the more important ideas. This requires discarding less important ideas and connecting ideas within a text. Accomplishing these goals requires student to write summaries of to-be-learned texts (often as part of or pre-requisite to text analysis and evaluation). Although summarizing a text is considered an instructional goal of its own right, the post is only concerned whether improve student performance on subsequent criterion tests on the same materials.
Description and Why it should work
As an introduction to the issues relevant to summarization, we begin with a description of a prototypical experiment. Bretzing and Kulhavy (1979) had high school juniors and seniors study a 2,000-word text about a fictitious tribe of people. Students were assigned to one of five learning conditions and given up to 30 minutes to study the text. After reading each page, students in a summarization group were instructed to write three lines of text that summarized the main points from that page. Students in a note-taking group received similar instructions, except that they were told to take up to three lines of notes on each page of text while reading. Stu- dents in a verbatim-copying group were instructed to locate and copy the three most important lines on each page. Students in a letter-search group copied all the capitalized words in the text, also filling up three lines. Finally, students in a control group simply read the text without recording anything. (A subset of students from the four conditions involving writing were allowed to review what they had written, but for present purposes we will focus on the students who did not get a chance to review before the final test.) Students were tested either shortly after learning or 1 week later, answering 25 questions that required them to connect information from across the text. On both On both the immediate and delayed tests, students in the summarization and note-taking groups performed best, followed by the students in the verbatim-copying and control groups, with the worst performance in the letter-search group
(see Fig. 3).
Bretzing and Kulhavy’s (1979) results fit nicely with the claim that summarization boosts learning and retention because it involves attending to and extracting the higher-level meaning and gist of the material. The conditions in the experiment were specifically designed to manipulate how much students processed the texts for meaning, with the letter-search condition involving shallow processing of the text that did not require learners to extract its meaning.
More than just facilitating the extraction of meaning, however, summarization should also boost organizational processing, given that extracting the gist of a text requires learners to connect disparate pieces of the text, as opposed to simply evaluating its individual components (similar to the way in which note-taking affords organizational processing;
So how strong is the evidence that summarization is a beneficial learning strategy? One reason this question is difficult to answer is that the summarization strategy has been implemented in many different ways across studies, making it difficult to draw general conclusions about its efficacy.
Studies show that “summarization is not one strategy but a family of strategies”. Depending on the particular instructions given, students’ summaries might consist of single words, sentences, or longer paragraphs; be limited in length or not; capture an entire text or only a portion of it; be written or spoken aloud; or be produced from memory or with the text present.
The focus on training students to summarize reflects the belief that the quality of summaries matters. If a summary does not emphasize the main points of a text, or if it includes incorrect information, why would it be expected to benefit learning and retention? Consider a study by Bednall and Kehoe (2011, Experiment 2), in which undergraduates studied six Web units that explained different logical fallacies and provided examples of each. Of interest for present purposes are two groups: a control group who simply read the units and a group in which students were asked to summarize the material as if they were explaining it to a friend. Both groups received the following tests: a multiple-choice quiz that tested information directly stated in the Web unit; a short-answer test in which, for each of a list of presented statements, students were required to name the specific fallacy that had been committed or write “not a fallacy” if one had not occurred; and, finally, an application test that required students to write explanations of logical fallacies in examples that had been studied (near transfer) as well as explanations of fallacies in novel examples (far transfer). Summarization did not benefit overall performance, but the researchers noticed that the summaries varied a lot in content; for one studied fallacy, only 64% of the summaries included the correct definition. Higher-quality summaries that contained more information and that were linked to prior knowledge were associated with better performance.
Several other studies have supported the claim that the quality of summaries has consequences for later performance. Garner (1982) showed that the quality of summaries matters: Under- graduates read a passage on Dutch elm disease and then wrote a summary at the bottom of the page. Five days later, the students took an old/new recognition test; critical items were new statements that captured the gist of the passage. Students who wrote better summaries (i.e., summaries that captured more important information) were more likely to falsely recognize these gist statements, a pattern suggesting that the students had extracted a higher- level understanding of the main ideas of the text.
Many different types of summaries can influence learning and retention; summarization can be simple, requiring the generation of only a heading or a single sentence per paragraph of a text , or it can be as complicated as an oral presentation on an entire set of studied material . Whether it is better to summarize smaller pieces of a text (more frequent summarization) or to capture more of the text in a larger summary (less frequent summarization) has been debated . The debate remains unresolved, perhaps because what constitutes the most effective summary for a text likely depends on many factors (including students’ ability and the nature of the material).
One other open question involves whether studied material should be present during summarization. Few studies pointed out that having the text present might help the reader to succeed at identifying its most important points as well as relating parts of the text to one another. However, summarizing a text without having it present involves retrieval, which is known to benefit memory, and also prevents the learner from engaging in verbatim copying. The answer to whether studied text should be present during summarization is most likely a complicated one, and it may depend on people’s ability to summarize when the text is absent.
Most of the research on individual differences has focused on the age of students, because the ability to summarize develops with age. However, younger students (e.g., middle school students) can benefit from summarization following extensive training and this benefit was linked to improvements in note-taking. It also it seems plausible that students with more domain-relevant knowledge would be better able to identify the main points of a text and extract its gist.
For the most part, characteristics of materials have not been systematically manipulated, which makes it difficult to draw strong conclusions about this factor, even though 15 years have passed establishing its importance.
The majority of summarization studies have examined the effects of summarization on either retention of factual details or comprehension of a text (often requiring inferences) through performance on multiple-choice questions, cued recall questions, or free recall. Other benefits of summarization include enhanced metacognition (with text- absent summarization improving the extent to which readers can accurately evaluate what they do or do not know and improved note-taking following training.
Whereas several studies have shown benefits of summarization (sometimes following training) on measures of application, others have failed to find such benefits. One week after learning, students who had summarized performed no differently than students in a control group who had only read the passages in answering questions that tapped a basic level of knowledge (fact and comprehension questions). Students benefited from summarization when the questions required the application or analysis of knowledge, but summarization led to worse performance on evaluation and synthesis questions.
Across studies, results have also indicated that summarization helps later performance on generative measures (e.g., free recall, essays) more than it affects performance on multiple- choice or other measures that do not require the student to produce information. Because summarizing requires production, the processing involved is likely a better match to generative tests than to tests that depend on recognition.
Finally, concerning test delays, several studies have indicated that when summarization does boost performance, its effects are relatively robust over delays of days or week. Similarly, benefits of training programs have persisted several weeks after the end of training.
Summarization would be feasible for undergraduates or other learners who already know how to summarize. For these students, summarization would constitute an easy-to-implement technique that would not take a lot of time to complete or understand. The only concern would be whether these students might be better served by some other strategy, but certainly summarization would be better than the study strategies students typically favor, such as highlighting and rereading. Relatively intensive training programs are required for middle school students or learners with learning disabilities to benefit from summarization.
Overall Assessment: Low Utility
On the basis of the available evidence, we rate summarization as low utility. It can be an effective learning strategy for learners who are already skilled at summarizing; however, many learners (including children, high school students, and even some undergraduates) will require extensive training, which makes this strategy less feasible. Although summarization has been examined with a wide range of text materials, many researchers have pointed to factors of these texts that seem likely to moderate the effects of summarization (e.g., length), and future research should be aimed at investigating such factors. Finally, although many studies have examined summarization training in the classroom, what are lacking are classroom studies examining the effectiveness of summarization as a technique that boosts students’ learning, comprehension, and retention of course content.
Bretzing, B. H., & Kulhavy, R. W. (1979). Notetaking and depth of processing. Contemporary Educational Psychology, 4, 145–153.
Bednall, T. C., & Kehoe, E. J. (2011). Effects of self-regulatory instructional aids on self-directed study. Instructional Science, 39, 205–226.
Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013). Improving Students’ Learning With Effective Learning Techniques: Promising Directions From Cognitive and Educational Psychology. Psychological Science in the Public Interest, 14(1), 4–58. https://doi.org/10.1177/1529100612453266
Garner, R. (1982). Efficient text summarization: Costs and benefits. Journal of Educational Research, 75, 275–279.