Memory experts would suggest that you can only remember seven items. Seven digits in a phone number would be something reasonable you could remember however a number is a fairly easily simple object to recall. Seven sentences or seven paragraphs is another story.
When someone says they are a good multi-tasker or can juggle many projects at once bet they are performing relatively simple tasks. Prioritizing, creative thought process, and content creation demand more energy from our brains which is why productivity experts will recommend doing these tasks early in the morning.
In David Rock’s book Your Brain at Work: Strategies for Overcoming Distraction, Regaining Focus, and Working Smarter All Day Long breaks down the chore of getting clear about how to maximize the energy from your brain to get more done.
He suggests when you have “too many actors on stage” (people/process/tasks) to account for it require much more brain power to sustain. Fewer actors doesn’t require as much effort to sustain high powered performance thinking for longer periods of time.