Figure 1. A snapshot of the choice procedure during a manipulation trial.

(1) The questionnaire is attached to a clipboard, with the questions distributed over two pages. A paper slip with moral statements is attached to the first page of the questionnaire to conceal the same, but negated set of statements printed on the page. (2) The participants rate their agreement with the statements on the first page of the questionnaire and (3) they turn to the second page, and (4) rate their agreement with a second set of principles. (5) When the participants are asked to flip back the survey to the first page to discuss their opinions, the add-on paper slip from (1) now sticks to a patch of stronger glue on the backside of the clipboard, and remains attached there. This reveals the altered set of principles on the first page, and when the participants now read the manipulated statements the meaning has been reversed (in effect, the equivalent of moving the actual rating score to the mirror side of the scale). (6) During the debriefing, the experimenter demonstrates the workings of the paper slip to the participants, and explains how the manipulation led to the reversal of their position. See http://www.lucs.lu.se/cbq/for a video illustration of the method and the interaction between experimenter and participants.