Bonus for attention questions?

Dear all,

This is my first time in the forum. I would like to ask your views on something.

I am designing a study in which I want to present participants with a text. The study is about whether this text changes in some way the participants’ views on an issue. Of course, it is important that participants read the text with enough attention to learn something from it.

I was planning to ask a few questions about specific facts contained in the text afterwards (but giving them the option to revisit the text if they want). And I was planning to give a bonus to those participants who get these questions right. However, I am worried this may crowd out participant’s intrinsic motivation to read the text; in other words, that by paying I will promote opportunistic behavior such as taking screenshots or just skimming through the text to get those specific facts right. In short, I am afraid of promoting the behavior I wanted to minimize.

What do you think? Have you encountered this issue? All responses will be welcome.

Thank you in advance.