Creative vs. Analytical Work
We've discussed here that willpower can be depleted. Our biggest store of self-discipline is early in the day. We try to duplicate that morning boost of willpower experience by breaking our day into units, so that we keep starting over again. The Unit System! Lee suggests that that early period of the day is best for creative work because that's when the prefrontal cortex of the brain is most active. A "study looked at morning and evening MRI scans and observed that mornings showed more connections in the brain—a key element to the creative process." He says this study also indicated that "analytical parts of the brain (the editing and proofreading parts) become more active as the day goes on."
Conclusion? Writers who have a number of projects underway may want to work on the ones that involve generating new material earlier in the day and the ones that require revision-like activities later.