The Effect of Overtraining on Discrimination Learning in the White Rats

A Factor Affecting Stimulus Classes Formation in Concurrent Discriminations in Rats

“…These findings suggest that animals form stimulus classes between the discriminative stimuli on a basis of the same response during overtraining . These findings agree with the cue-associations theory advocated by Nakagawa (1978Nakagawa ( , 1986Nakagawa ( , 1992. According to the cue-associations theory, animals learn a connection between a positive stimulus and an approach response as well as a connection between a negative stimulus and an avoidance response for each discrimination task in the original training.…”

“…These findings demonstrate that the animals establish stimulus classes between stimuli on a basis of the same response during overtraining in the conditional discrimination learning but not in criterion training. These findings are in line with the cue-associations theory (Nakagawa, 1978(Nakagawa, , 1986(Nakagawa, , 1992. That is, these findings make it clear that the animals need two stages to establish stimulus classes between the discriminative stimuli on a basis of the same response in the conditional concurrent discrimination learning: The first stage is that the animals learn a connection between a positive stimulus and an approach response followed by food as well as a connection between a negative stimulus and an avoidance response followed by no food for each discrimination task on reaching the criterion in Phase 1 discrimination training, and the second one is that they form associations between the discriminative stimuli on a basis of the same response following the same consequence during overtraining.…”

“…Positive ORE (Overtraining Reversal Effect) occurred in Group W, whereas negative ORE occurred in Group P. These findings are in line with the cue-associations theory (Nakagawa, 1978(Nakagawa, , 1986(Nakagawa, , 1992. That is, according to the cueassociations theory, as a result of cue associations, the reversal of the one discrimination after overtraining -in the whole condition should exert a synergistic influence upon the reversal of the other discrimination.…”

“…In each group, suppression generalized more readily from N to the stimulus that had received the same initial training as had been given to N. Nakagawa (1986Nakagawa ( , 1992, Zentall, Steirn, et al (1991), Zentall, Sherburne, et aI., (1992), Delius et al (1995), Dube et al (1993), and Hall et al (1993) suggest that rats and pigeons can form stimulus classes on a basis of reinforcement concordance. Nakagawa (1978Nakagawa ( , 1986Nakagawa ( , 1992 has asserted that, during the original discrimination training, rats learn a connection between a positive stimulus and an approach response as well as a connection between a negative stimulus and an avoidance response for each discrimination task. But during overtraining they also form associations between the discriminative stimuli on a basis of the same response following the same consequence in concurrent discriminations.…”

“…Using a whole-partial reversal procedure which compared rats' performances on whole reversal sessions (both stimulus pairs reversed, from A+C-, B+O-to A-C+, B-O+ for example) with those on partial reversal sessions (only one pair reversed, from A-C+, B-O+ to A+C-, B-0+ for example), Nakagawa (1978Nakagawa ( , 1986Nakagawa ( , 1992Nakagawa ( , 1998 has shown that rats form stimulus classes between the discriminative stimuli on the basis of the same response during overtraining in concurrent discriminations. In Nakagawa's experiments, rats were trained to criterion or overtrained on two concurrent discriminations (A+C-, B+O-for example) in Phase 1 training in both a simultaneous (Nakagawa, 1986(Nakagawa, , 1998) and a go-no go successive concurrent discriminations (Nakagawa, 1992(Nakagawa, , 1998.…”