My daughter says no a hundred times a day. She said yes just a couple times in her life.

Why is there such a difference? Of course, the right answer is hereditary grumpiness. But suppose that it’s not that. I am no expert in psychology, but here’s a primitive theory:

If you accept something, you must have some criteria against which you evaluate. If you are not capable of setting acceptance criteria, you are more prone to whims.

So if asked Do you want to put on a red cap? The little brain goes like I want my cap to have the color with wavelength of 570nm, and you are offering me a 650nm one. you must be kidding and so the child says no! Had the child more flexible a reasoning, it would have had acceptance criteria of a couple of tens of nanometers and would have assumed that a red cap is a better substitute for a yellow one than, say, a green one, although green cap is 20nm closer to yellow than a red one. Having had made the decision about this 20nm difference, the child would say yes!. But for the time being, my daughter is too unsophisticated when calculating nanometers.