Difficulty adjustment in practice exercises has been shown to be beneficial for learning. However, previous research has mostly investigated close-ended tasks, which do not offer the students multiple ways to reach a valid solution. Contrary to this, in order to learn in an open-ended learning task, students need to effectively explore the solution space as there are multiple ways to reach a solution. For this reason, the effects of difficulty adjustment could be different for open-ended tasks. To investigate this, as our first contribution, we compare different methods of difficulty adjustment in a user study conducted with 86 participants. Furthermore, as the practice behavior of the students is expected to influence how well the students learn, we additionally look at their practice behavior as a post-hoc analysis. Therefore, as a second contribution, we identify different types of practice behavior and how they link to students' learning outcomes and subjective evaluation measures as well as explore the influence the difficulty adjustment methods have on the practice behaviors. Our results suggest the usefulness of taking into account the practice behavior in addition to only using the practice performance to inform adaptive intervention and difficulty adjustment methods.

翻译：实践练习中的难度调节已被证明对学习有益。然而，以往研究主要关注封闭式任务，这类任务不提供学生达成有效解决方案的多种途径。与之相反，在开放式学习任务中，由于存在多种解题路径，学生需要有效探索解空间。因此，难度调节的效果可能在开放式任务中有所不同。为探究这一问题，作为第一项贡献，我们通过一项包含86名参与者的用户研究，比较了不同难度调节方法。此外，由于学生的练习行为预计会影响学习效果，我们作为事后分析进一步观察了其练习行为。因此，作为第二项贡献，我们识别了不同类型的练习行为及其与学生学习成果和主观评价指标的关系，并探讨了难度调节方法对练习行为的影响。研究结果表明，除了仅使用练习表现来指导自适应干预和难度调节方法外，考虑练习行为也具有实用价值。