Figure 1

Schematic of the AX-CPT-s. (A) The first 160 trials (pre-switch) represented a standard implementation of the AX-CPT. Subjects were to respond with a left mouse click to an “X” probe whenever it followed an “A” cue, and a right mouse click for all other cue–probe combinations. The target “X” probe followed the “A” cue on 70% of the trials. (B) In the version of the AX-CPT used here, the standard trials were followed by 96 additional trials (post-switch), for which subjects were informed that they were to switch the response pattern—so that they now were to respond with a left mouse click to a “Y” probe whenever it followed an “B” cue, and a right mouse click for all other cue–probe combinations. The other cue–probe combinations included foils involving the old cue (“A”) and/or probe (“X”), with all different combinations presented equally often. The foils allowed investigation of interference effects from the previously valid cue and probe.