Teaching Stimulus-Stimulus Relations to Minimally Verbal Individuals: Reflections on Technology and Future Directions.

This paper discusses recent methodological approaches and investigations that are aimed at developing reliable behavioral technology for teaching stimulus-stimulus relations to individuals who are minimally verbal and show protracted difficulty in acquiring such relations. The paper has both empirical and theoretical content. The empirical component presents recent data concerning the possibility of generating rapid relational learning in individuals who do not initially show it. The theoretical component (1) considers decades of methodological investigations with this population and (2) suggests a testable hypothesis concerning some individuals exhibit unusual difficulties in learning. Given this background, we suggest a way forward to better understand and perhaps resolve these learning challenges.

Assessing the contributions of S-O and R-O associations to differential-outcome matching through outcome reversals.

Pigeons were trained on symbolic matching with 2 samples, 2 pairs of comparisons, and different outcomes for the correct responses within each comparison pair. For one group, the 2 samples were also associated with different outcomes, whereas for another group, they were not. When the response-outcome (R-O) relations for one pair were subsequently reversed, the group trained with differential sample-outcome (S-O) associations was significantly disrupted in its performance on both reversed- and nonreversed-outcome trials. By contrast, the group trained with just differential R-O associations was disrupted only on reversed-outcome trials. These results were replicated when the outcomes on the initially nonreversed trials were then reversed. The findings indicate that differential S-O associations, when present, have a stronger influence on matching performances than differential R-O associations. They are also consistent with hierarchical and configural models of discriminative control.

Transfer of pigeons' matching to sample to novel sample locations.

This study examined the conditions under which conditional stimulus control by the sample stimuli in three-key matching-to-sample paradigms would generalize across the different possible sample locations. In Experiments 1 and 2, the samples appeared on the left and right side keys during initial training and then on the center key during testing. Transfer of pigeons' matching performances to the center-key samples was evident after both identity and symbolic matching training. In Experiment 3, pigeons trained on symbolic matching with two side-key samples or with a side-key and a center-key sample generally transferred their learned matching performances to those samples when they subsequently appeared in the remaining (novel) location. These results indicate that, when two-choice conditional discriminations are learned with more than one sample location, the visual characteristics of the sample per se predominantly come to control the pigeons' comparison choices. This finding encourages the use of the multiple-location training procedure as a way of reducing control by location, thus providing a more discriminating test of symmetry in animals.