I know this is pretty unusual. I also know from first-hand experience that night owls tend to hate us morning people, who are up with the sun and at least reasonably coherent by six a.m., if not always showered and fully dressed. (Hell, I'm retired. Fully dressed sometimes doesn't happen at all, especially when the weather is warm.)
The result, though, is that I fade out pretty early in the evening. I'm one of those people who, when invited to a party, seriously consider saying no if the start time is after seven in the evening. By eight I want to be reading a book, and the times I'm still awake at ten are few and far between.
But the lowest time for me, energy-wise, is right after lunch. Even when I get adequate sleep, I go through a serious slump in the early afternoon, even if I was chipper beforehand. (Okay, given my personality, I'm never really chipper. I also don't do "perky" or "bubbly." So think about it as "chipper as compared to my baseline demeanor.")
Turns out, I'm not alone in finding the early afternoon a tough time to be productive, or even to stay awake. As I learned from a paper in The Journal of Neuroscience, the problem is a fluctuation in the brain's reward circuit -- it, like many other human behaviors, is on a circadian rhythm that affects its function in a regular and predictable fashion.
The problem is a misalignment of the putamen (part of the brain's reward circuit) and the suprachiasmatic nucleus, which acts as a biological clock. The putamen is most active when you receive a reward you weren't expecting, and least active when you expect a reward and don't get one. The cycling of the suprachiasmatic nucleus stimulates the putamen to expect a reward after lunch, and then when it doesn't come -- one in the afternoon is nowhere near quitting time or happy hour, and most people's schedules don't accommodate an early afternoon nap -- the expected payoff doesn't happen.
The result: sad putamen. Drop in motivation levels.
"The data suggest that the brain’s reward centres might be primed to expect rewards in the early afternoon, and be ‘surprised’ when they appear at the start and end of the day," said neuroscientist Jamie Byrne of Swinburne University. "[The] brain is ‘expecting’ rewards at some times of day more than others, because it is adaptively primed by the body clock."
Me, I wonder why this priming happens at all. What sort of reward did we receive in the early afternoon in our evolutionary history that led to this response becoming so common? Honestly, I wonder if it was napping; an afternoon nap has been found not only to improve cognitive function, but (contrary to popular opinion) doesn't generally interfere with sleeping at night. Having evolved on the African savanna, where the early afternoon can be miserably hot, it could be that we're built to snooze in the shade after lunch, and now that most of us are on an eight-to-five work schedule, we can't get away with it any more. But the circadian rhythm we evolved is still there, and our energy levels plummet after lunch.
It reminds me of the three weeks I spent in Spain and Portugal a few years ago. I was astonished at first by the fact that no one ate dinner -- even considered eating dinner -- until nine in the evening. (On one of our first days there, we went to a restaurant at about eight, and asked the waiter if we could be seated at a table. His response was, "Why?" I think he was genuinely puzzled as to why anyone might want dinner at such a ridiculously early hour.) But once we got the hang of it -- a big lunch with a bottle of fine red wine, then a three-hour siesta during the hottest part of the day, when businesses close their doors so there's nothing much to do but sleep anyhow -- even I was able to stay up late with no problem.
All in all, a very pleasant lifestyle, I thought.
So we now know there is a neurological reason for the early-afternoon energy slump. Kind of a fascinating thing how much we're at the mercy of our biological clock. But anyhow, I better get busy and get some chores done. Time's a-wasting, and I'm guessing by lunchtime I won't be feeling like doing much but hitting the hammock and conking out for a while.
This week's Skeptophilia book recommendation of the week is pure fun, and a great gift for any of your friends who are cryptid fanciers: Graham Roumieu's hilarious Me Write Book: It Bigfoot Memoir.
In this short but hysterically funny book, we find out from the Big Guy's own mouth how hard it is to have the reputation for being huge, hairy, and bad-smelling. Okay, even he admits he doesn't smell great, but it's not his fault, as showers aren't common out in the wilderness. And think about the effect this has on his self-image, not to mention his success rate of advertising in the "Personals" section of the newspaper.
So read this first-person account of the struggles of this hirsute Everyman, and maybe even next time you're out hiking, bring along a little something for our australopithecene distant cousin.
He's very fond of peach schnapps.
[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]