If you are thinking of slipping a magnet behind the right ear of some lady (I did) you should first ask yourself; “is her moral compass filtering out lustful desires or homicidal desires?” ;^)
lol.
I think by telling the participants that they could either tell the truth or lie, they changed it to a game rather than a moral compass, since they already said that either response was “acceptable” for the study.
I was just in a classroom not long ago where the teacher told the kids to make up a back jacket for a book about their life - but that it could be about their real life or about a fictional life. The kids who wrote about a fictional life had no reason to believe that they were lying, since they had already been given permission to make it fictional. Same thing would apply here, I think.
I was hoping there would be a "Power" setting on the thing. Like they have for lasers that allow you to adjust between "delicate eye surgery" and "vaporize jeep."