Digital learning materials must be aligned with learner characteristics to foster equitable and adaptive learning environments, addressing students' diversity. Tailoring learning materials to adapt to learners' choices and pre-existing individual interests is critical for engaging, motivating, and deepening learning.

When students have agency in their learning, they experience greater autonomy, which is linked to increased intrinsic motivation and better learning outcomes. Motivation plays a key role in learning success, with interest-driven learning enhancing cognitive engagement, leading to better retention and transfer of knowledge. However, limited research has explored whether individual interest amplifies or diminishes the effects of choice on motivation.

This study investigates the interaction between choice and motivation in digital learning environments, examining how autonomy moderates the effect of choice on motivation and learning success. Ninety-two university students were randomly assigned to either a control group or an experimental group, where they could choose the sequence of learning videos.

Learning success was assessed through retention and transfer tasks, with autonomy, intrinsic motivation, situational interest, and cognitive load considered as potential moderators. The findings reveal that choice positively impacts learning success, particularly for individuals with low to moderate individual interest. However, for learners with high individual interest, choice negatively affected learning success.

Mediation analyses suggest that autonomy mediates the relationship between choice and learning success, reinforcing the importance of learner agency in digital environments. Contrary to expectations, choice did not significantly influence intrinsic motivation, likely due to the inherently engaging nature of the video materials. These results challenge the assumption that choice universally benefits all learners and underscore the need for personalized instructional design. While choice can enhance learning for less-interested students, it may increase cognitive load for highly interested learners, potentially diverting attention from content processing.

This finding aligns with research on cognitive effort regulation, suggesting that instructional choices should be tailored to individual characteristics rather than applied uniformly. The study highlights the importance of motivation and adaptivity in digital learning materials and advocates for nuanced implementations of choice that consider students' intrinsic interest levels. Future research should explore these interactions across diverse learning domains and instructional modalities to refine variables for adaptivity in digital learning materials.

Keywords: Personal Learning Environments (PLEs), Technology-Enhanced Learning, Instructional Design (and Curriculum Priorities).