Paying attention to more than one thing "at the same time" - is not humanly possible. So when you are simultaneously doing two tasks that demand attention, what you are actually doing is rapid context switching. The thing to understand is that - “attention has inertia”. Context switching has two implications:
1. It drains your energy - You have limited energy available every day. If you spend most of your energy in context switching, very less is available for actual work. And if you over-work, you cause real physical damage to yourself.
2. You can’t do any deep work - Deep work requires attention on a single thing for a sustained period of time.
The idea is to work with your attention - not against it. The best way to do that is to reduce context switching and eliminate attention residue. Here is how:
1. Short-duration tasks - When you pick a task, finish it completely before moving on to the next one. Have distraction-free slots for work and batch similar tasks together.
2. Long-duration tasks - Pause-and-resume approach. When you pause a task, take a mental dump of its current state. This helps in two ways - first, your attention will not linger when you move to the next task and second, it will be easier to pick up when you resume that task.