Is metacognition an affective, cognitive, or behavioural variable?

Is metacognition an affect or cognitive or behaviour variable ?

I want to study variation in metacognition and working memory ability level and its effect on inductive reasoning. Therefore i am trying to understand the cognitive system. I read some literature stating that metacognition is cognition awareness, which implies that it is a cognitive variable, but some say that it is an opinion about how far they can do metacognitive ability. I read about a factor analysis of the Junior Metacognitive Awareness Inventory.

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It seems like there are a lot of ideas out there as to what metacognition really is. Having done my MS thesis in understanding how people learn in engineering programs, I typically think about metacognition as "knowing how to learn." It's typically a goal of engineering education to teach students these skills.