Figure 6. The different trial types in the two versions of the Paired-Associates Learning (dPAL and sPAL) tasks and in the Visuo-Motor Conditional Learning (VMCL) task.

In both PAL paradigms, stimuli are rewarded when located in a specific location: left for the Flower, central for the Plane, right for the Spider. However, in a first variant of the task (dPAL), two different stimuli are presented at the same time, whereas two similar stimuli are presented in the second variant of the task (sPAL). In the VMCL paradigm, only two different trial types coexist for a given rule; note that the current rule can be inverted („If Equal appears, go Right; if Icicle appears, go Left“), which is why all groups were counterbalanced. S+: rewarded stimulus (correct response); S-: non-rewarded stimulus (incorrect response). Picture from Campden Instruments Ltd.; reprinted with permission.