1982 年 1 巻 1 号 p. 59-62
Pigeons were trained on PAN ambiguous-cue problems which involved three stimuli: a positive stimulus, a negative stimulus, and an ambiguous stimulus, to which responding was sometimes reinforced and sometimes nonreinforced depending on the paired stimulus. All subjects attained higher level of performance in terms of correct response on the trials where the ambiguous stimulus was paired with the negative stimulus than on the trials where the ambiguous stimulus was paired with the positive stimulus. This result could be interpreted by the interfering effect ascribed to the positive property of the ambiguous stimulus. It was, however, found that level of performance in terms of latencies of correct responses differed markedly between the types of problems: that is, responses to A stimulus on NA trials had longer latencies than those to P on PA trials. This finding suggests some interfering effect of alternative property of the ambiguous stimulus, the negative property, which can be detected by measuring response latencies.