Text Coherence & Self-Explanation, I

When I write about text coherence, I usually refer to what I call the Coherence Principle—a principle that involves two standards for content: order and packaging.*

These two standards are somewhat similar to the two standards of the Accuracy Principle--clarity and precision—in that the first is a consumer-level (student-level) standard, and the second is a distributor-level (teacher-level) and/or producer-level (content-level) standard.


From a research standpoint, however, text coherence is something very different and much simpler. The authors of the paper (PDF)¹ I will discuss in this and the next post, Ainsworth and Burcham, follow the lead of many researchers, including Danielle McNamara (2001), in conceiving of text coherence as "the extent to which the relationships between the ideas in the text are made explicit." In addition to this conceptualization, the authors also adopt guidelines from McNamara, et al. (1996)² to improve the coherence of the text used in their experiment—a text about the human circulatory system. These guidelines essentially operationalize the meaning of text coherence as understood by many of the researchers examining it:

(1) Replacing a pronoun with a noun when the referent was potentially ambiguous (e.g., replacing 'it' with 'the valves'). (2) Adding descriptive elaborations to link unfamiliar concepts with familiar ones and to provide links with previous information presented in the text (e.g., replacing 'the ventricles contract' with 'the ventricles (the lower chambers of the heart) contract'). (3) Adding connectives to specify the relation between sentences (e.g., therefore, this is because, however, etc.).

Maximal coherence at a global level was achieved by adding topic headers that summarised the content of the text that followed (e.g., 'The flow of the blood to the body: arteries, arterioles and capillaries') as well as by adding macropropositions which linked each paragraph to the overall topic (e.g., 'a similar process occurs from the ventricles to the vessels that carry blood away from the heart').

Many studies have found that improving text coherence (i.e., improving the "extent to which the relationships between the ideas in the text are made explicit") can improve readers' memory for the text. Ainsworth and Burcham mention several in their paper, including studies by Kintsch and McKeown and even a study by Britton and Gulgoz, which I discussed a couple of years ago here.

What Britton and Gulgoz find is that when "inference calls"—locations in text that demand some kind of inference from the reader—are "repaired," subjects' recall of a text is significantly improved over that of a control group. These results may sum up the advantages seen across research studies in improving text coherence: in general, although there are certainly very few if any simple, straightforward, unimpeachable results available in the small collection of text-coherence studies, researchers consistently find that "making the learner's job easier" in reading a text by making the text more coherent provides for significant improvement in readers' learning from that text.

Self-Explanation

In some sense, the literature on self-explanation tells a different story from the one that emerges from the text-coherence research. Ainsworth and Burcham define self-explanation in this way:

A self-explanation (shorthand for self-explanation inference) is additional knowledge generated by learners that states something beyond the information they are given to study.

The authors then go on to describe some advantages offered to readers by the self-explanation strategy, according to research:

Self-explanation can help learners actively construct understanding in two ways; it can help learners generate appropriate inferences and it can support their knowledge revision (Chi, 2000). If a text is in someway [sic] incomplete . . . then learners generate inferences to compensate for the inadequacy of the text and to fill gaps in the mental models they are generating. Readers can fill gaps by integrating information across sentences, by relating new knowledge to prior knowledge or by focusing on the meaning of words. Self-explaining can also help in the process of knowledge revision by providing a mechanism by which learners can compare their imperfect mental models to those being presented in the text.

Thus, whereas text coherence advantages learners by "repairing" (i.e., removing) inferences, self-explanation often produces gains even when—and perhaps especially when—text remains minimally coherent.

What shall we make of this? Which is more important—text coherence or self-explanation? And how do they (or can they) interact, if at all? These are the questions Ainsworth and Burcham attempt to address in their experiment, which I will discuss in my next post.


* I'm putting this seemingly irrelevant information at the top of this post, so that I can refer to it later in the context of the research I write about here.

1: S AINSWORTH, S BURCHAM (2007). The impact of text coherence on learning by self-explanation Learning and Instruction, 17 (3), 286-303 DOI: 10.1016/j.learninstruc.2007.02.004

2: Danielle McNamara, Eileen Kintsch, Nancy Butler Songer, Walter Kintsch (1996). Are Good Texts Always Better? Interactions of Text Coherence, Background Knowledge, and Levels of Understanding in Learning From Text Cognition and Instruction, 14 (1), 1-43 DOI: 10.1207/s1532690xci1401_1