I read the study. The wager is:

  $0.10 awarded for a correct answer

  $0.10 deducted for a wrong answer

  $0.00 (no change for a refusal to answer)

There was no detail on whether participants were actually going to be paid, or if they were in the negative at the end, be expected to pay their losses.

I am inclined to believe the effects of the study are real, but not nearly as pronounced as the data. If there were more serious amounts of money on the table, I think common sense would prevail.