Multitasking reduces productivity
A lot of people claim to be able to multitask, meaning working on multiple tasks at the same time. However, in reality that just means switching between the tasks in some intervals - the more rapid the switches, the more it looks like the tasks are actually done “at the same time”.
However, every switch requires they switch context. We can imagine these contexts as little boxes with all of the information we have on the task. To start work on one, we’ll have to get the box, put it in front of us, take out everything to start working and set it up in the way we like. Only then we can actually do what we set out to do. At the end of the session for that specific task, we put everything back in the box, write down any information that we have on our minds, so that we don’t forget it until we start working next time (our minds are for having ideas, not for storing them).
Whenever we want to switch between two tasks, we need to put everything into one box, and get another box out.
If we’d try having both boxes out at the same time, it’d be much harder to separate notes from one and the other, and we probably wouldn’t be able to lay everything out the way we’d like to have it ideally for the different tasks. Meaning there’s compromises to be made.
While we might not actually have physical boxes for our tasks, and we can automate a lot of setup in the digital realm (open windows, put them where they’re supposed to go, open files/documents,…), there’s always one thing that we cannot automate, and that’s our mind. And our mind is also much better at retrieving information from a context, if it’s already set up in it.
So if we have two tasks, it’ll be much quicker to just do them one after another, than it is to do them “at the same time”. Once a task is done, it’s done. We won’t have to come back to it, so we can just throw out the box for it completely (in this metaphor any information that’s relevant for multiple tasks exists in all of those boxes…).
This means if we start some tasks later (after finishing others), we can actually get them done earlier, than if we would have started all tasks as soon as possible.