The work hasn't started yet. You're already tired.
You open your task list. There are seven things that could be done today. You scan them. You compare importance. You think about what you're in the mood for, what's most urgent, what you've been avoiding, what will feel best to complete.
Ten minutes later, you've chosen a task. You're also slightly more depleted than when you opened the list.
Decisions Cost the Same Resource as Focus
In 1998, Roy Baumeister and colleagues published findings that would reframe how we understand mental fatigue. They found that decisions, self-control, and focused concentration all draw from the same finite cognitive resource (*Journal of Personality and Social Psychology*, 1998).
This means every decision you make about what to work on consumes the same resource you'll need to focus on the work itself.
Choosing between seven tasks requires evaluation, comparison, and commitment - each of which costs something. By the time you've decided, you've spent cognitive resources on the meta-problem (what to do) before touching the actual problem (doing it).
The more options, the higher the cost. This is why a to-do list of ten tasks feels more exhausting to start from than a to-do list of two.