  Successful learning depends on learners' ability to sustain attention, which
is particularly challenging in online education due to limited teacher
interaction. A potential indicator for attention is gaze synchrony,
demonstrating predictive power for learning achievements in video-based
learning in controlled experiments focusing on manipulating attention. This
study (N=84) examines the relationship between gaze synchronization and
self-reported attention of learners, using experience sampling, during
realistic online video learning. Gaze synchrony was assessed through
Kullback-Leibler Divergence of gaze density maps and MultiMatch algorithm
scanpath comparisons. Results indicated significantly higher gaze
synchronization in attentive participants for both measures and self-reported
attention significantly predicted post-test scores. In contrast, synchrony
measures did not correlate with learning outcomes. While supporting the
hypothesis that attentive learners exhibit similar eye movements, the direct
use of synchrony as an attention indicator poses challenges, requiring further
research on the interplay of attention, gaze synchrony, and video content type.
