As a result of these intersections, four dominant types of regulation processes can be distinguished: (1) high-level content individual regulation; (2) low-level content individual regulation; (3) high-level content co-regulation; and (4) low-level content co-regulation.
Planning and monitoring, for a total number of 156 in high-level content episodes and 91 in low-level content episodes.
Planning was frequent within both high-level and low-level content co-regulation episodes, so it does not make a difference to our interpretation.
Wherever high-level content co-regulation episodes were observed, such codes were highly frequent, while they rarely appeared in the low-level content episodes.
The content-processing continuum concerns the mental activities invested to develop content knowledge; this goes from low-level content up to high-level content processing.
The first research question was related to the occurrence of monitoring and planning issues in high-level content and low-level content co-regulation episodes.
Although they can be oriented towards all possible aspects of the assigned task, low-level content episodes do not contribute to the learning of a specific topic; they simply include sentences and expressions discussing a given step within the procedure (see two examples of low-level content co-regulation episodes in Additional file 1: Appendix S1).
A Spearman's non-parametric correlation analysis showed that positive and significant correlations were more frequently attached to positive socioemotional interactions than to negative ones, both in high- and low-level content co-regulation episodes.
In high-level co-regulation episodes, questions (68%) and tentativeness of explanation (32%) were frequent; in low-level content episodes, questions were very frequent (91%) while tentativeness of explanations were rather infrequent (9%).
The Chi square test did not reveal any significant association with types of episodes, thus revealing that socioemotional indicators were evenly distributed across high-level and low-level content co-regulation episodes.
Content-based retrieval of audiovisual materials has to deal with the "semantic gap" [30], the mismatch between the low-level content descriptors and the high-level concepts required by the search tasks.
