Fig. 3.

Schematic diagram of trial timings in method-of-single-stimuli (MSS) and paired-comparison (PC) variants of the landmark task. The fixation cross and the stimuli are not drawn to scale. In the MSS variants (left side), the actual transecting position in each trial was dictated by the applicable staircase, and the response requested could be binary (in MSS-2R) or ternary (in MSS-3R). In the PC-3R task (right side), in which a ternary response was requested, the interval in which the standard configuration transected at the center was presented (Interval 1 in this illustration), and the locations at which the test configuration in the other interval was transected were dictated by the applicable staircase in that trial