The Role of Meaningful Stimuli in Large Stimulus Classes

The present experiment examined the effect of having the D-stimuli as meaningful pictures when establishing 18 conditional discriminations and testing for the emergence of three 7-member equivalence classes (A -> B -> C -> D -> E -> F -> G). Twenty participants were randomly assigned to two main experimental groups. In one group, the participants were exposed to training and testing with abstract stimuli only (the ABS group). In the other group, the participants were exposed to D-stimuli as meaningful pictures and the A, B, C, E, F, and G stimuli as abstract stimuli (the PIC group). If the participants in the PIC group did not form equivalence classes, they repeated the experiment in a new condition (DA-as-PIC) that had a new stimulus set different from the PIC group where the D and A stimuli are meaningful stimuli whereas the B, C, E, F, and G stimuli were abstract stimuli. The participants who did not form equivalence classes in the DA-as-PIC condition repeated the experiment in a new condition (DAG-as-PIC) that had a new stimulus set different from the PIC and DA-as-PIC where the D, A, and G stimuli are meaningful stimuli whereas the B, C, E, and F stimuli were abstract. The main findings from the experiment showed that 1 of 10 participants in the ABS group formed equivalence classes, whereas 5 of 10 participants in the PIC group formed equivalence classes. Furthermore, the result showed that three of the five participants who did not form equivalence classes in the PIC group formed classes in the DA-as-PIC condition. Finally, two of the five participants who did not form equivalence classes in the DA-as-PIC condition formed classes in the DAG-as-PIC condition.

Automated summary

The study compared two experimental groups, one trained and tested with abstract stimuli and the other with meaningful pictures as D-stimuli. The results showed that participants in the meaningful pictures group were more likely to form equivalence classes.