On the Role of Meaningful Stimuli

We investigated how the pre-training of abstract stimuli with some meaningful pictures with different delay durations will influence the formation equivalence classes. Eighty-four college students were randomly assigned to seven groups of equal number of members. Participants were trained to form three 3-node 5-member equivalence classes (A->B->C->D->E) under the simultaneous protocol. For participants in the ABS group, all of the stimuli used were abstract shapes, while in the PIC group, the C stimuli were pictures and the A, B, D, and E stimuli were the same abstract shapes as in the ABS group. For the other five groups, participants were pre-trained to form arbitrary relations between the C-abstract shapes and the C-picture stimuli in the first two groups prior to class formation. These five groups varied in the delay duration of the disappearance of the sample stimulus and the appearance of the comparison stimuli. In one group (SMTS), the sample remained until the comparison choice was made, while in the others (0s, 3s, 6s and 9s), the arbitrary conditional discriminations with the C stimuli were trained using 0s, 3s, 6s and 9s delayed matching-to-sample procedures, respectively.