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Three adult subjects were taught a set of two-choice simultaneous discriminations, with three positive and three negative stimuli; all possible combinations of positive and negative stimuli yielded nine different pairs. The discriminations were repeatedly reversed and rereversed, the former positive stimuli becoming negative and the former negative stimuli… (More)
This study examined stimulus class membership established via stimulus-reinforcer relations. Mentally retarded subjects learned conditional discriminations with four two-member sets of visual stimuli (A, B, C, and D). On arbitrary-matching trials, they selected comparison stimuli B1 and B2 conditionally upon samples A1 and A2, respectively, and C1 and C2… (More)
Adults with autism and young children first learned to match one-element comparison stimuli to two-element sample stimuli. Test conditions then examined whether each of the individual sample elements (a) controlled selections of the comparison stimuli to which they were related during training, (b) were interchangeable with one another as either sample or… (More)
The correlation of runoff phosphorus (P) with water-extractable phosphorus (WEP) in land-applied manures and biosolids has spurred wide use of WEP as a water quality indicator. Land managers, planners, and researchers need a common WEP protocol to consistently use WEP in nutrient management. Our objectives were to (i) identify a common WEP protocol with… (More)
In two experiments (ns = 3 plus a previously tested child, and 2, respectively), children learned delayed matching with complex samples, each consisting of a form and a printed nonsense word. Forms or printed words were comparison stimuli. For form comparisons, selecting the form identical to that in the preceding sample was reinforced. For printed word… (More)