From [1]
The scientific study of multitasking over the past few decades has revealed important principles about the operations, and processing limitations, of our minds and brains. One critical finding to emerge is that we inflate our perceived ability to multitask: there is little correlation with our actual ability. In fact, multitasking is almost always a misnomer, as the human mind and brain lack the architecture to perform two or more tasks simultaneously. By architecture, we mean the cognitive and neural building blocks and systems that give rise to mental functioning. We have a hard time multitasking because of the ways that our building blocks of attention and executive control inherently work. To this end, when we attempt to multitask, we are usually switching between one task and another. The human brain has evolved to single task.
Fair enough, so it's a misnomer. Let's call it task switching then, since we don't actually do tasks at the same time, but switch from one to the other. A Claude Code session helpfully prints a small tldr summary of the ongoing session, so that one can quickly onboard again to the task at hand. I do not find that draining, personally.