2.1.1 Should you stop reading to look words up?
It depends. Looking up words slows you down, and you may be able to make reasonable sense of their context without having to. For example, I found it fairly easy to guess the meaning of ‘habituation’ in paragraph 8, from the way it was discussed. However, I looked it up on the internet anyway, as I happened to have my computer on. I also looked up ‘real income’ and ‘marginal tax’ and found useful clarification of their meanings.
You have to decide how important a word seems to be. Do you feel you are missing something by not knowing it? Does it keep appearing? If you just carry on reading, the word may become clearer as you experience it being used (after all, that's how we get to know the meaning of most words).
Sometimes it's not one particular word that's difficult, but a string of them. For example, when I read ‘clinical depression, assessed professionally through population surveys’, I had to slow down. Having taken in the meaning, it seemed to me that ‘depression’ was the main word I needed to pay attention to, so I underlined it. (See Section 4, Reading actively.)