1. Each participant was given two pieces of white card
2. One card with a line labelled - X
3. The second card with three comparison lines (A, B, C)
4. The participants would have to identify which one of the lines on the second card was the same length of X
5. One of the three comparison lines was almost clearly equal to X – the other two were clearly wrong
6. On each trail participants were asked to state out load which of the comparison lines was equal to X
7. The genuine participant would answer last or second to last