And you might want to read the book that you are critiquing. I understand that this is inevitable to proceed impulsively in this day and age, but you will find that everything (yes, everything) is backed up by what most find as an annoyingly long series of endnotes. Here is the part that you should have read:
You want to tackle it when you tend to have the most zip, and that when that is depends upon your circadian rhythm. Some of us are morning larks, relentlessly chipper and active early in the morning, filling gyms during in the pre-dawn hours. Others are night owls, slow starters whose energy levels peak later in the day. Night owls are more likely to be procrastinators, with a chronobiology best suited for after- hours; forcing themselves into an unnatural schedule, they gulp down caffeine in the morning in order to wake up, and alcohol in the evening to wind down.
And here are the cites:
Díaz-Morales, J., Ferrari, J., & Cohen, J. (2008). Indecision and avoidant procrastination: The role of morningness-eveningness and time perspective in chronic delay lifestyles. Journal of General Psycholology, 135(3), 228–240.
Digdon, N., & Howell, A. (2008). College students who have an eveningness preference report lower self-control and greater procrastination. Chronobiology international, 25(6), 1029.
Ferrari, J. R., Harriott, J. S., Evans, L., Lecik-Michna, D. M., & Wenger, J. M. (1997). Exploring the time preferences of procrastinators: Night or day, which is the one? European Journal of Personality, 11(3), 187–196.
Hess, B., Sherman, M. F., & Goodman, M. (2000). Eveningness predicts academic procrastination: The mediating role of neuroticism. Journal of Social Behavior and& Personality, 15(5), 61–74.
Klein, S. (2009). The secret pulse of time: Making sense of life’s scarcest commodity. Cambridge, MA: Da Capo Lifelong Books.
While I don’t have subscriptions to all those journals, so I can’t check exactly what those studies proved and didn’t prove, all I can say is that this example: “filling gyms during in the pre-dawn hours” tells me we’re still not talking about the same thing, i.e. mental energy. I think there’s a big difference between feeling physically energetic on one hand and feeling mentally focussed and creative on the other.
Also, while I find it easy to accept that there are two kinds of people as mentioned above, I will still be looking for explicit proof that “most people” are “morning larks”, like the original quote said.
Thanks for your patience.