Money makes the world go ’round, but getting too much of it has a downside. University of Amsterdam researchers had 104 participants look at two images and determine which one had the higher contrast. Using a scale of 50 to 100 percent, they rated their level of confidence in their decision, and they were told they would win or lose money (of varying amounts) depending on if they got it right. Researchers found the money helped participants make good decisions in some sense– they were better at discriminating between the right and wrong answer. However, it made those who were confident in their decisions even more sure of themselves. This may happen because the prospect of a monetary reward may change an individual’s physiological state and, by extension, a person’s confidence in their judgement.