Figure 2.

Example (A) transformed two-up, one-down staircase, and (B) weighted up-two, down-one staircases. (Note that in the present paper, “up” corresponds to “harder.”) Correct and incorrect responses are highlighted by green ticks and red crosses, respectively. In the transformed staircase, the unit step size was of unit length. Two correct answers were required to increase difficulty whereas only one incorrect answer was required to decrease difficulty. This staircase will converge on a threshold of 70.7% correct. In the weighted staircase, upward steps were twice as large as downward steps, and a step occurred after every answer (correct or incorrect). This staircase will converge on a threshold of 33.3% correct.