How to assess participant awareness of experimental deception without inducing awareness? I am designing a memory experiment with a deceptive critical trial, wherein an item is swapped without the participant's knowledge.  

What is the best way to determine if the participant has noticed the swap, without actually informing them of it?

I.e., asking the participant 'did you notice the swap we just made' is rather informative about the possibility of a swap :)  

Current thoughts:


a statement at the beginning asking them to mention any inconsistencies noticed
a direct question directly after the swap, and 
a direct question at the end of the experiment 


I think the first and second are likely to induce noticing (the latter by comparison to earlier memories that otherwise would not have been performed) and the last to potentially under-report.
Procedures like this are often called "funnel debriefing" procedures, and they basically consist of an extended version of what you already had in mind.

You begin with some very general questions about the nature of the experiment (e.g., "Do you have any initial thoughts or reactions about this experiment?"), then move on to some questions that are slightly more specific, but still not fully revealing (e.g., "Why do you think we showed you X?", "Did you notice anything unusual or inconsistent about task Y in the experiment?"), and finally terminate with direct inquiries of awareness (e.g., "Did you notice that we swapped one of the images during task Y?").

These questions may or may not be accompanied by recall or recognition tasks where awareness is gauged through participants' performance on the memory task.

Unfortunately there is typically little or no standardization (at least that I have seen) of how extensive these procedures should be, or for how to score and otherwise handle the results.