Why would a heavier mental load push someone toward a better strategy?
The counterintuitive idea is that making a well-practiced method harder to execute can nudge a solver to look for something better. In an Einstellung situation, a person knows a trained procedure that works, so there is little reason to search for an alternative—even when a superior one exists. When researchers increased the cognitive load of that trained procedure by making it more complex, participants found alternatives more efficiently, measured by how many trials it took to discover them [2]. The effect was significant for participants with high working memory capacity [2].
One proposed explanation is that the load ties up the mental resources that would otherwise keep the familiar procedure running smoothly, making the trained route less attractive and freeing the solver to explore [2]. That is a possible mechanism rather than a settled purpose. The study also argues that earlier inconsistent results may have come from load manipulations, such as a secondary task, that burden both the trained and the alternative procedure at once, and from ignoring how quickly alternatives are found [2].
What high working memory capacity actually buys under load
Working memory capacity is the amount of information a person can hold and manipulate at once. In mathematical problem solving, students with high capacity remembered and managed information well, which supported more advanced strategies, and they had better attention control, which helped them find varied appropriate solutions [1]. Students with low capacity lost attention control as tasks grew more complex, missed important information, and did not recheck their work [1]. That pattern is consistent with high-capacity solvers having more room to notice and pursue an alternative when the usual route gets harder.
The efficiency finding fits this picture: the benefit of higher load on discovering alternatives was concentrated in the high-capacity group [2]. The study frames this as evidence that timing matters—how many trials pass before an alternative appears—when judging how working memory shapes flexible problem solving [2].
When the high-capacity advantage disappears
In a category fluency task, where people retrieved animal names, high-capacity individuals performed better under normal conditions and were more likely to use an effective strategy—retrieving animals by scientific classification [3]. Under increased cognitive load, however, there were no working-memory-related performance differences, and working memory no longer predicted strategy use [3]. Using the classification strategy helped performance regardless of load, and that strategy use was more strongly related to retrieval performance than working memory was [3].
So the answer depends on what kind of strategy is being measured. Discovering a better alternative to a trained procedure is not the same as spontaneously selecting a retrieval strategy in a fluency task. The first showed a high-capacity advantage under load [2]; the second showed the advantage washing out under load [3]. The studies also differ in task and in how load was created, so the comparison is suggestive rather than a direct contradiction.
What this means for learning and instruction
Working memory capacity is consistently linked to mathematical performance: one study of 15- to 17-year-olds found a significant relationship between capacity and math ability, with high-capacity students outperforming low-capacity peers [1]. A study of 98 undergraduates found capacity accounted for 74.5% of the variance in integral calculus performance, with higher-capacity students doing better on complex tasks [5]. That study recommends that instructors consider cognitive load and individual memory capacity when designing instruction, including scaffolding for students with lower capacity [5].
The strategy findings add a nuance: load can sometimes help flexible solvers find alternatives, but it can also erase the strategy-use advantage of high-capacity people in other tasks [2][3]. For a curious reader, the practical takeaway is that cognitive load is not simply bad or good—its effect on finding alternatives depends on the task and on the solver's working memory capacity.
Sources used in this answer
How Does Working Memory Capacity Affect Students’ Mathematical Problem Solving?
Working memory capacity significantly affected mathematical ability, and high-capacity students used more advanced strategies and found varied appropriate solutions, while low-capacity students lost attention control and missed information as task complexity increased.
Effect of cognitive load and working memory capacity on the efficiency of discovering better alternatives: A survival analysis
Higher cognitive load from a more complex trained procedure increased the efficiency of discovering alternatives, and this effect was significant for participants with high working memory capacity.
Classifying retrieval strategies as a function of working memory.
High working memory individuals used an effective retrieval strategy more often under normal conditions, but under increased cognitive load there were no working-memory-related performance differences and working memory did not predict strategy use.
Age-related Differences in the Effects of Working Memory Capacity and Cognitive Load on Word Recognition: An Eye Tracking Study
In low working memory capacity individuals, response time increased under lower cognitive load, unlike the high capacity group.
The influence of students' working memory capacity on solving calculus problems
Working memory capacity had a significant positive relationship with calculus problem-solving ability, accounting for 74.5% of the variance, with higher-capacity students outperforming lower-capacity students on complex tasks.