Our working memory has a limited capacity for task-related information. To perform complex tasks, we should offload some mental load onto an external medium.
Article: Working Memory and External Memory
Working memory is a temporary storage where our brain deposits information critical to the current task. Unlike long-term or short-term memory, working memory is like things you need to know but don't want to remember later.
This memory system is task-oriented and has a limited capacity. When the information required for a task exceeds its capacity, we must offload current items in our working memory to make room for new information. Constantly swapping items in our working memory is inefficient and error-prone. For example, consider the task of mentally multiplying 357 by 123. It can be challenging due to the need to remember each carry number while doing multiplication.
An effective way to make the memory system more effective is to offload items from working memory to easily accessible external memory. For instance, performing calculations on paper is easier than purely in our minds because of the visual support provided by the external medium.
This principle also explains why reading long articles on a laptop is often easier than on a mobile phone. A larger screen can act as an extension of working memory, reducing the need to scroll and remember previous content. Similarly, using comparison tables for shopping or creating customized spreadsheets are examples of relieving the load on our working memory by externalizing information management.
You can also learn more about working memory at Huberman's Tools to Enhance Working Memory & Attention.