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 participantsā€™ 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 participantā€™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.