Effects of Training Level and Locus of N-R Transitions on Resistance to Discrimination

Abstract

Four groups of 10 rats were trained on a successive brightness differential conditioning problem. Two groups received transitions from nonrewarded (N) trials to rewarded (R) trials (N-R transitions) within S+ and two groups received transitions from N in S− to R in S+ (S−S+ transitions). Half of the rats in each condition experienced those transitions from the outset of training; the remaining rats first learned the discrimination under conditions that precluded N-R or S−S+ transitions and subsequently those transitions were introduced. N-R transitions in S+ and S−S+ transitions experienced from the outset of training, and N-R transitions in S+ introduced after the discrimination had been learned, all had a like effect on discrimination and retarded discrimination compared with the late introduction of S−S+ transitions into the situation.