The actors knew the true aim of the experiment, but were introduced to the subject as other participants. Each student viewed a card with a line on it, followed by another with three lines labeled "A", "B", and "C" (see accompanying figure). One of these lines was the same as that on the first card, and the other two lines were clearly longer or shorter (i.e., a near-100% rate of correct responding was expected). Each participant was then asked to say aloud which line matched the length of that on the first card. Before the experiment, all actors were given detailed instructions on how they should respond to each trial (card presentation). They would always unanimously nominate one comparator, but on certain trials they would give the correct response and on others, an incorrect response. The group was seated such that the real participant always responded last.