Text Coherence & Self-Explanation, II

The study (PDF) I introduced in my previous post lays out what seems like a provocative dilemma in its introduction.

On the one hand, a comprehensive—though shallow—read of the text coherence literature tells us that improved text comprehension can be achieved by "repairing" text incoherence—by closing informational gaps in text. On the other hand, research shows that significant improvements in learning from text can come from employing a strategy of self-explanation during reading—a method that practically feeds off textual incoherence.

Ainsworth and Burcham tease out a good question from this apparent dilemma:

Is maximally or minimally coherent text more beneficial to learning when accompanied by self-explanations? Two alternative hypotheses are proposed:

(a) The minimal text condition when accompanied by self-explanation training will present the optimal conditions for learning. Minimal text is hypothesized to increase self-explaining, and self-explanation is known to improve learning. Consequently, low knowledge learners who self-explain will not only be able to overcome the limitations of less coherence but will actively benefit from it as they will have a greater chance to engage in an effective learning strategy.

(b) Maximally coherence [sic] text accompanied by self-explanation will present the optimal condition for learning. Although maximal text is hypothesized to result in less self-explanation than minimal text, when learners do self-explain they will achieve the benefits of both text coherence and self-explanation.

Which of these hypotheses do you think will win out?

The Experiment

Forty-eight undergraduate students were randomly separated into four groups, each of which was assigned either a maximally coherent text (Max) or a minimally coherent text (Min) about the human circulatory system. Each group was also given either self-explanation training (T) or no training at all (NT):


All forty-eight students completed a pretest on the subject matter, read their assigned text using self-explanation or not, and then completed a posttest, which was identical to the pretest. The results for each of the four groups are shown below (the posttest results have been represented using bars, and the pretest results have been represented using line segments):


The pretest and matching posttest each had three sections, as shown above. Each of these sections comprised different kinds of questions, but all of the questions assessed knowledge of the textbase:

The textbase contains explicit propositions in the text in a stripped-down form that captures the semantic meaning.

As you can see, each of the four groups improved dramatically from pretest to posttest, and those subjects who read maximally coherent text (Max) performed slightly better overall than those who read minimally coherent text (Min), no matter whether they used self-explanation during reading (T) or not (NT). However, the effect of text coherence was not statistically significant for any of the three sections of the tests. Self-explanation, on the other hand, did produce significant results, with self-explainers scoring significantly higher on two of the three sections than non–self-explainers.

In addition to the posttest, subjects also completed a test comprised of "implicit questions" and one comprised of "knowledge inference questions" at posttest only. The results for the four groups on these two tests are shown below.


Each of these two tests assessed students' situation models:

The situation model (sometimes called the mental model) is the referential mental world of what the text is about.

The researchers found that self-explainers significantly outperformed non–self-explainers on both tests. Those who read maximally coherent text also outperformed their counterparts (readers given minimally coherent text) on both tests. However, this effect was significant for only one of the tests, and approached significance for the other test (p < 0.08).

More on this later.

Reference:

AINSWORTH, S., & BURCHAM, S. (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