Powell R W
J Exp Anal Behav. 1971 Jan;15(1):109-16. doi: 10.1901/jeab.1971.15-109.
Three pigeons received visual discrimination training under both multiple variable-ratio extinction and variable-interval extinction schedules. All birds developed nearly perfect discrimination. When punishment for every tenth response during food reinforcement was presented, responding decreased as shock intensity increased. At the same time, responding during extinction, which was not punished, increased at intermediate punishment intensities, but returned to low levels under severe punishment. A second procedure, in which punishment and no-punishment sessions alternated unsystematically, was employed with two of the birds. The results under this procedure essentially replicated the data obtained as punishment shock intensity increased gradually.
三只鸽子在多重可变比率消退和可变间隔消退程序下接受视觉辨别训练。所有鸽子都形成了近乎完美的辨别能力。当在食物强化期间对每第十次反应进行惩罚时，随着电击强度的增加，反应减少。同时，在不进行惩罚的消退期间，反应在中等惩罚强度下增加，但在严厉惩罚下恢复到低水平。对其中两只鸽子采用了第二种程序，即惩罚和不惩罚的阶段无规律地交替进行。该程序下的结果基本上重复了随着惩罚电击强度逐渐增加而获得的数据。
