Neural Mechanisms Underlying the Impact of Explanation Strategies on Video Learning of Declarative Knowledge.

Instructional videos are now widely used to support the learning of declarative knowledge, but it remains unclear whether different explanation targets shape this process in distinct ways at the neural level. In the present study, functional near-infrared spectroscopy (fNIRS) was used to examine how self-explanation and explaining to others influence behavioral performance and oxygenated hemoglobin (HbO) responses within the sampled prefrontal and temporoparietal regions across different phases of declarative video learning. Sixty undergraduates were randomly assigned to either a self-explanation condition or an explaining-to-others condition while learning from instructional videos. Hemodynamic responses were recorded during the construction, explanation, and memory-retention phases. At the behavioral level, participants in the self-explanation condition showed better immediate associative-retention performance than those in the explaining-to-others condition, whereas the two groups did not differ in changes in academic self-efficacy. At the neural level, within-condition analyses showed that self-explanation was associated with significant task-related activation across a broader set of sampled frontal-linguistic regions of interest (ROIs), including the frontopolar cortex, bilateral dorsolateral prefrontal cortex (DLPFC), and bilateral Broca's areas. In the between-condition analyses, explaining to others was associated with greater HbO responses during the explanation and memory-retention phases, particularly in the left DLPFC, left Broca's area, right temporal gyrus, right Wernicke's homologue, and fusiform gyrus. No between-group differences in intra-brain functional connectivity survived false discovery rate correction. Mediation analyses further identified significant statistical indirect effects of explanation strategy on learning performance through activation in the right Wernicke's homologue. Taken together, these findings suggest that explanation targets differentially shape immediate associative retention and cortical processing across learning phases in this specific video-learning context. Relative to explaining to others, self-explanation was associated with better immediate associative retention and less extensive recruitment of language-related support regions during later learning phases.