An illustration of pattern-trial rules used in a PL test. The asterisk-like target moves among four locations on the screen, which is divided into four equal quadrants by two intersecting white lines. The movement of the target during the pattern-trial test is predictable in 75% of cases, as determined by three specific rules: (a) a horizontal target movement is followed by a vertical target movement, (b) a vertical target movement is followed by a diagonal target movement, and (c) a diagonal target movement is followed by a horizontal movement. The fourth movement of the target during the pattern trials is unpredictable. In the control state, individuals are subjected to only random target movements. During the experimental test, individuals are subjected to blocks of patterns and required to determine the expected projectory of imminent movement, and their subsequent reaction time is recorded. Reproduced with permission from Schizophrenia Research (84).