Here are two quotes from Education and Learning to Think, an interesting little research-based book published by the National Research Council way back in 1987!

Higher order thinking is nonalgorithmic. That is, the path of action is not fully specified in advance.

Higher order thinking tends to be complex. The total path is not "visible" (mentally speaking) from any single vantage point.

Higher order thinking often yields multiple solutions, each with costs and benefits, rather than unique solutions.

Higher order thinking involves nuanced judgment and interpretation.

Higher order thinking involves the application of multiple criteria, which sometimes conflict with one another.

Higher order thinking often involves uncertainty. Not everything that bears on the task at hand is known.

Higher order thinking involves self-regulation of the thinking process. We do not recognize higher order thinking in an individual when someone else "calls the plays" at every step.

Higher order thinking involves imposing meaning, finding structure in apparent disorder.

Higher order thinking is effortful. There is considerable mental work involved in the kinds of elaborations and judgments required. (p. 3)

The seventh item on the list, self-regulation, is one that I think is particularly lacking in many K-12 schools because the teachers "call the plays" so much of the time...

Here's what I think is the money quote:

The goals of increasing thinking and reasoning ability are old ones for educators. . . . But these goals were part of the high literacy tradition; they did not, by and large, apply to the more recent schools for the masses. Although it is not new to include thinking, problem solving, and reasoning in someone's school curriculum, it is new to include it in everyone's curriculum. It is new to take seriously the aspiration of making thinking and problem solving a regular part of a school program for all of the population . . . It is a new challenge to develop educational programs that assume that all individuals, not just an elite, can become competent thinkers. (p. 7)

I liked this book. It's very short, but it made me think. I give it 4 highlighters.