Somewhat Hangchiong. This is really more spot specific. The place it mainly applies is where you have a hand that you normally think is a very strong hand and you'd be happy to get all in, but if you stop and look at the board, maybe in this case that hand isnt really as strong as you'd think. I guess its an extension of 1st level thinking really.

Erpel, spot on. Its not only our range we're looking at, its his range. If we're at the bottom of our range, but we think he'll get in with a lot worse then getting all in isnt so bad, but we need to be thinking about both ranges. It especially applies when we're the one pushing. People think "I have x hand, I want to get all in!" without thinking "hang on, what hands will call me if I push?" Sometimes you wont like the answer. Thats where range manipulation comes into it. Perhaps by calling we allow a villain to make mistakes with a wider range, whereas if we push we let him play correctly by folding or calling depending on his actual hand?