Prior knowledge is one of the strongest contributors to comprehension, but there is little specificity about different aspects of prior knowledge and how they impact comprehension. This article introduces the Multidimensional Knowledge in Text Comprehension framework, which conceptualizes prior knowledge along four intersecting dimensions: amount, accuracy, specificity, and coherence. Amount refers to how many relevant concepts the reader knows. Accuracy refers to the extent to which the reader’s knowledge is correct. Specificity refers the degree to which the knowledge is related to information in the target text. Coherence refers to the interconnectedness of prior knowledge. Conceptualizing prior content knowledge along these dimensions deepens understanding of the construct and lends to more specific predictions about how learners process information. Considering knowledge across multiple dimensions is crucially important to the development and selection of prior knowledge assessments and, in turn, educators’ ability to capitalize on learners’ strengths across various comprehension tasks.

Computer-based learning environments (CBLEs) provide unprecedented opportunities for personalized learning at scale. One such system, iSTART (Interactive Strategy Training for Active Reading and Thinking) is an adaptive, game-based tutoring system for reading comprehension. This paper describes how efforts to increase personalized learning have improved the system. It also provides results of a recent implementation of an adaptive logic that increases or decreases text difficulty based on students’ performance rather than presenting texts randomly. High school students who received adaptive text selection showed increased sense of learning. Adaptive text selection also resulted in greater pre-training to post-training comprehension test gains, especially for less-skilled readers. The findings demonstrate that system-driven, just-in-time support consistent with the goals of personalized learning benefit the efficacy of computer-based learning environments.

For decades, educators have relied on readability metrics that tend to oversimplify dimensions of text difficulty. This study examines the potential of applying advanced artificial intelligence methods to the educational problem of assessing text difficulty. The combination of hierarchical machine learning and natural language processing (NLP) is leveraged to predict the difficulty of practice texts used in a reading comprehension intelligent tutoring system, iSTART. Human raters estimated the text difficulty level of 262 texts across two text sets (Set A and Set B) in the iSTART library. NLP tools were used to identify linguistic features predictive of text difficulty and these indices were submitted to both flat and hierarchical machine learning algorithms. Results indicated that including NLP indices and machine learning increased accuracy by more than 10% as compared to classic readability metrics (e.g., Flesch-Kincaid Grade Level). Further, hierarchical outperformed non-hierarchical (flat) machine learning classification for Set B (72%) and the combined set A + B (65%), whereas the non-hierarchical approach performed slightly better than the hierarchical approach for Set A (79%). These findings demonstrate the importance of considering deeper features of language related to text difficulty as well as the potential utility of hierarchical machine learning approaches in the development of meaningful text difficulty classification.

Research suggests that promoting metacognitive awareness can increase performance in, and learning from, intelligent tutoring systems (ITSs). The current work examines the effects of two metacognitive prompts within iSTART, a reading comprehension strategy ITS in which students practice writing quality self-explanations. In addition to comparing iSTART practice to a no-training control, those in the iSTART condition (n = 116) were randomly assigned to a 2 (performance threshold: off, on) × 2(self-assessment: off, on) design. The performance threshold notified students when their average self-explanation score was below an experimenter-set threshold and the self-assessment prompted students to estimate their self-explanation score on the current trial. Students who practiced with iSTART had higher posttest self-explanation scores and inference comprehension scores on a transfer test than students in the no training control, replicating previous benefits for iSTART. However, there were no effects of either metacognitive prompt on these learning outcomes. In-system self-explanation scores indicated that the metacognitive prompts were detrimental to performance relative to standard iSTART practice. This study did not find benefits of metacognitive prompts in enhancing performance during practice or after the completion of training. Such findings support the idea that improving reading comprehension strategies comes from deliberate practice with actionable feedback rather than explicit metacognitive supports.