Title System versus Self: Using Adaptive Learning Technologies to Promote the Self-regulated Use of Desirable Difficulties Summary This study aims to move beyond one-size-fits-all type of instructional support when designing learning strategy interventions. Specifically, it compares the effectiveness of two forms of adaptive support: System- and self-regulated support. In the former, the system decides students’ unique instructional needs based on three parameters: knowledge of learning strategies, interpretation of subjective experiences, and use of interleaving. Depending on this measurement, it provides students with a respective combination of instructional support. In the self-regulated support condition, students have the autonomy to design their own instruction, using the same instructional components. Participants were psychology students at Maastricht University. The study was conducted and designed on SoSciSurvey platform. Data Description 1. Diagnostic assessment (all students) • Aw. Awareness of interleaving • Ef. Interpretation of effort • Pl. Interpretation of perceived learning 2. IC. Instructional components (only in the self-regulated condition) • IC01: refutations on the effectiveness of learning strategies • IC02: refutations on the role of subjective experiences • IC03: guided study phase • Binary coded: 0 did not request support; 1 requested support. 3. Use of interleaving • Nsw. Number of switch • Sw. Proportion of switch. • Chronologically ordered (per task). 4. Ft. Fatigue questions. 5. Classification performance • Scores at the item level: Named with the names of categories - Binary coded: 0 incorrect; 1 correct • Scores aggregated: Test.1, Test.2, Test.3 6. Condition: indicating the experimental condition (system versus self).