By Carolina Kuepper-Tetzel
In a recent paper, Danzglock, Berger, and Hänze (1) investigated the effects of combining collaborative learning with interleaved practice using complex material in physics in 376 secondary school students. Interleaved practice is when tasks or concepts are practiced together instead of organizing their practice in a blocked (and homogenous) fashion. To give a simple example: When practicing math problems, interleaving would, for instance, mean to practice the application of different formula to calculate edges (e), corners (c), faces (f), and angles (a) in geometry within the same activity (e.g., practice sequence ecfa, cfae,…). In contrast, blocked practice would have separate activities for each formula and practice them one at a time without mixing (e.g., practice sequence eeee, cccc,…). Interleaving has been shown to be an effective strategy to boost long-term retention of simple concepts (to learn more about interleaved practice see our past posts here for examples). However, the benefits of interleaved practice for the learning of more complex ideas and topics are less clear and sometimes showing an advantage of blocked practice (2).
Interleaved practice requires the learner to evaluate each task and make a decision how to solve it because each task will be different to the one solved previously. Particularly when working on problems that look similar at the surface, but which require different operators to solve them, interleaved practice comes with additional cognitive demands compared to blocked practice. These cognitive demands are likely to be exacerbated when studying complex concepts in an interleaved practice which could hamper learning. Danzglock, Berger, and Hänze (1) were interested in exploring collaborative learning as a scaffolding mechanism and boundary condition for interleaved practice in complex physics learning. They proposed that successful collaborative learning allows students to a) explain ideas to each other, discuss solutions to problems, ask each other questions and b) engage in transactive and externalizing processes by sharing thoughts with peers which can free up individual cognitive load. Since one of the driving factors of interleaved practice is that it allows for comparing, contrasting, and evaluating concepts, collaborative learning could support these processes specifically and potentially reveal interleaving benefits for the acquisition of complex concepts.
In their experiment, a total of 30 secondary physics classes were randomly assigned to either collaborative learning or individual learning conditions. Within each class, students were then assigned to the interleaved practice or the blocked practice condition. During the learning phase, students engaged with a digital educational game to practice the concepts of magnetic and electric fields. In the blocked practice condition, 18 tasks on magnetic fields were presented and then 18 tasks on electric fields. In the interleaved practice condition, magnetic and electric field tasks alternated. Students in the individual learning condition worked on these tasks on their own, whereas students in the collaborative learning condition worked in pairs. Collaborative engagement was encouraged through prompts, and it was made sure that each student in a pair contributed equally (i.e., took control of the game). Final assessments were administered immediately after practice and 8 weeks later. In addition to the main learning performance assessments, students’ prior knowledge, cognitive load, self-concept, interest, and experience with collaborative learning were assessed as control variables.
The results showed that collaborative learning indeed brought out the benefit of interleaved practice on both performance tests (i.e., immediate and delayed) on complex physics content. For the blocked practice condition, however, it did not matter whether students had practiced individually or in pairs. Thus, the advantage of interleaving over blocking only occurred in the collaborative condition, but not in the individual condition. Looking at intrinsic cognitive load measures, students in the collaborative-interleaved group perceived the material as less complex compared to students in the other conditions. This finding is in line with the idea that working in pairs on interleaved problems seems to facilitate externalizing cognitive processes and co-creating of knowledge.
To conclude, the current experiment shows that interleaved practice can be a successful learning technique for the learning of complex concepts if its processes are supported by collaborative learning. The reduction of intrinsic cognitive load was identified as a factor in explaining this finding. Thus, strategic scaffolding can unfold the benefits of learning techniques that are labelled as desirable difficulties in order to…well…making them desirable and not just difficult.
(cover image by Artem Podrez via Pexels)
References
-
Danzglock, M., Berger, R., & Hänze, M. (2026). Interleaved practice in physics benefits from collaboration. Learning and Instruction, 102, 102307.
-
Yan, V. X., Sana, F., & Carvalho, P. F. (2024). No Simple Solutions to Complex Problems: Cognitive Science Principles Can Guide but Not Prescribe Educational Decisions. Policy Insights from the Behavioral and Brain Sciences, 11(1), 59-66.