The conspecific organisms can be a special discriminative stimulus for the social learning in many species. For example, it would be advantageous for survival to recognize the physical state of the others in case of food selection or searching, especially in the omnivorous and social animals. In the present study, we examined whether the Japanese quails (Coturnix coturnix japonica) and the rats (Rattus norvegicus) could discriminate between the physical states of the other conspecifics.
The "observer" quails were trained to discriminate between the video clips of the conspecific animals ("demonstrator") that showed normal or abnormal behavior. One group (Depressant Group) was trained with the abnormal conspecifics injected with ketamine as the positive stimuli (S+), whereas the other group trained with those injected with methamphetamine (stimulant drug) as S+. The negative stimuli (S-) were the normal demonstrators (without drug) for both groups. In the generalization tests, both groups showed the categorical generalization, normal or abnormal, to the novel stimuli, regardless of the two types of the physical state (depressive or hyperactive). Such generalization was also found in the human subjects, but they responded differentially to the two types of abnormal state.
The "observer" rats were trained to discriminate between the states of "demonstrator" rats placed in the back of the experimental cage. The "demonstrator" rats were either satiated or deprived of the foods. The satiated rats could freely access to the food for 23 hours prior to the experimental sessions, whereas the deprived rats were not given any food for 23 hours before the sessions. The rats were able to discriminate between them, and showed generalization to the novel stimuli. Further analysis revealed that they used the movement of the demonstrators as the major discriminative cue.
Our results indicated that the quails and the rats can discriminate between the physical states of the conspecifics. Thus, it would be quite possible that they might use such ability to avoid the toxic foods and to access to the abundant food patch, for their successful survival.

Yamazaki, Y. 1999 Stimulus equivalence in nonhuman animals. The Japanese Journal of Animal Psychology, 49, 107-137. (in Japanese with English Abstract)
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Yamazaki, Y. & Watanabe, S. 2000 From concept to logic. Watanabe, S (Ed.), Comparative cognitive science of mind (Chapter 4). Kyoto: Minerva, Pp. 155-224.
Yamazaki, Y. & Sato, M. 2001 Effects of sequential responses on spatial delayed matching-to-sample in pigeons (Columba livia). The Psychological Record, 51, 271-285.

YAMAZAKI, Yumiko
Department of Psychology,
Keio University
2-15-45, Mita, Minato-ku, Tokyo
108-8345, Japan
yumyam@rondo.plala.or.jp