Example of low- vs high-focus thought as a function of fatigue/alertness:
Suppose your briefcase clasp is stuck.
If you are well-rested and alert, you’re likely to be in a state of high focus. You will "methodically run down the list of factors that cause briefcases to jam, plan a course of action, and do it."
What if you're not so well-rested?
As we set off down-spectrum, thinking becomes less penetrating and more diffuse, consciousness gradually “spreads out” and…emotion starts to replace problem-solving as the glue of thought. …When a briefcase jams and the owner’s focus level is medium, instead of a cool logical analysis he is more likely to think “last time I did this, it opened.” Thought is less analytical, more concrete. He might simply give the thing a good whack.
What if the briefcase owner is getting tired and bothered?
Confronted with a stuck briefcase towards the bottom of the spectrum, the owner is not likely to solve the problem at all. He is more likely to find himself thinking “that was some hot muggy day when I bought this damned briefcase in Milford—did I overpay?—I pay more than I need to for most things. But I’m better than Bill Schwartz in that regard—Schwartz’s dinner party last fall was kind of fun—Molly sure didn’t want to go—she looked nice in that short midnight blue dress, though—Columbus Avenue, we got the thing in that shop around 76th Street…”