FACTORS INFLUENCING INHIBITORY STIMULUS CONTROL - DISCRIMINATION TRAINING AND PRIOR NON-DIFFERENTIAL REINFORCEMENT

In Exp. I, shallow U‐shaped gradients of inhibition in the line‐orientation dimension were obtained from birds that had a vertical (0°) line on a green surround correlated with extinction and a blank green surround correlated with reinforcement. Birds that had massed extinction in the presence of the 0° line showed flat gradients. Thus, discrimination training, but not massed extinction, appears to generate inhibitory control. In Exp. II, as in studies of control by a stimulus correlated with punishment, non‐differential training across the line‐orientation dimension preceded further sessions. Steep inverted gradients about the 0° line were obtained after discrimination training with the 0° line correlated with extinction. Gradients obtained after massed extinction tended to be flat. Again, discrimination training was critical in obtaining negative gradients of stimulus control. 1969 Society for the Experimental Analysis of Behavior