抄録
The effectiveness of a treadle and a key as operanda in shaping and maintaining avoidance responding under a free operant situation was examined in pigeons. Pigeons were trained to press a treadle, to press a key, or to do both according to the prescribed order. The within-subjects comparison showed that the treadle pressing response was more easily shaped and maintained than the key pressing response. Also the key pressing response observed in the present study was different from the pigeon's key pecking behavior typically observed in the experiments with positive reinforcement.