A new psychology experiment uses techniques from popular magic to demonstrate that people misunderstand and misrepresent the reasons behind their own choices. Participants were asked to choose which of two alternatives they preferred, and subsequently to justify their choice. However, experimenters surreptitiously swapped the alternatives immediately after the participant had announced a choice, and most never noticed, in most cases even giving "reasons" for why they had "chosen" the option they were presented with (even though they had, in fact, picked the other option).