Visual attention in retarded adults: combining stimuli which control incompatible behavior.

Eight severely retarded young men learned color and line-tilt discrimination. After 95% accuracy was achieved for both dimensions, they were combined to form "conflict-compound" stimuli in which prior reinforcement history was reversed for one element of the compound and unchanged for the other. When responding to the compound was 95% accurate, control exerted by each element was measured. The unchanged element consistently exercised control in agreement with the reinforcement contingencies associated with the compound, regardless of whether it was color or line orientation. The reversed element, which had a conflicting prior history or reinforcement, most often exerted control associated wtih original training, or no control, suggesting that it had been "ignored" during the compound. Conflict compounds produced selective attention. When elements were combined to form "compatible-compound" stimuli, both exercised control in agreement with the compound in post-tests. Selective attention was not produced by compatible compounds.