Transfer of functions based on equivalence class formation using musical stimuli.

Empirical evidence has supported that musical excerpts written in major and minor modes are responsible for evoking happiness and sadness, respectively. In this study, we evaluated whether the emotional content evoked by musical stimuli would transfer to abstract figures when they became members of the same equivalence class. Participants assigned to the experimental group were submitted to a training procedure to form equivalence classes comprising musical excerpts (A) and meaningless abstract figures (B, C, and D). Afterward, transfer of function was evaluated using a semantic differential. Participants in the control group showed positive semantic differential scores for major mode musical excerpts, negative scores for minor mode musical excerpts, and neutral scores for the B, C, and D stimuli. Participants in the experimental groups showed positive semantic differential scores for visual stimuli equivalent to the major modes and negative semantic differential scores for visual stimuli equivalent to the minor modes. These results indicate transfer of function of emotional content present in musical stimuli through equivalence class formation. These findings could provide a more comprehensive understanding of the effects of using emotional stimuli in equivalence class formation experiments and in transfer of function itself.

Effect of observing response requirements to sample and comparison stimuli on the establishment of reject control (sample/S- relations).

The establishment of sample/S- relations (or reject control) during conditional discrimination training (AB, BC) affects transitivity (AC), equivalence (CA) and reflexivity (AA, BB, CC) test outcomes. The present study parametrically evaluated the effects of different observing patterns to comparison stimuli on the establishment of reject control during baseline conditional relation training. A matching-to-sample with observing requirements (MTS-OR) procedure was implemented during AB and BC conditional discrimination training. During training, the participants were required to observe the sample and incorrect comparison on every trial before responding. In addition, the participants were divided into three groups that differed regarding the percentage of training trials on which they were prevented from observing the correct comparison stimuli: 25%, 50%, and 75%. Once the mastery criteria were achieved during training, transitivity (AC), symmetry (BA, CB), equivalence (CA), and reflexivity (AA, BB, CC) tests were conducted with all comparison stimuli visible from the beginning. The results suggest that the number of errors during transitivity, equivalence, and reflexivity tests progressively increased as participants were prevented from observing the correct comparison on a greater number of trials during training. Symmetry test results, however, were not affected by the experimental manipulation. Moreover, the number of participants showing reject-control patterns during tests slightly increased and the number of participants showing select-control patterns decreased as a function of the number of trials on which the participants were prevented from observing the correct comparison. Thus, we suggest that observing patterns during training is a relevant variable that affects equivalence test outcomes.