J Exp Anal Behav. 1970 Sep;14(2):201-11. doi: 10.1901/jeab.1970.14-201.
In the first of two experiments, responses of two pigeons were maintained by multiple variable-interval, variable-ratio schedules of food reinforcement. Concurrent punishment was introduced, which consisted of a brief electric shock after each tenth response. The initial punishment intensities had no lasting effect upon responding. Then, as shock intensity increased, variable-ratio response rates were suppressed more quickly than variable-interval response rates. When shock intensity decreased, variable-interval responding recovered more quickly, but the rates under both schedules eventually returned to their pre-punishment levels. In the second experiment, the following conditions were studied in three additional pigeons: (1) With each shock intensity in effect for a number of sessions, punishment shock intensity was gradually increased and decreased and responding was maintained by multiple variable-ratio, fixed-ratio schedules of food reinforcement; (2) Changes in punishment shock intensity as described above with responding maintained by either a variable-ratio or a fixed-ratio schedule, which were presented on alternate days; (3) Session-to-session changes in shock intensity with responding maintained by multiple variable-ratio, fixed-ratio schedules. Responding under the two schedules was suppressed to approximately the same extent by a particular shock intensity. Also, post-reinforcement pauses under the fixed-ratio schedule increased as response suppression increased.
在两项实验中的第一项实验中，两只鸽子的反应通过多种可变间隔、可变比率的食物强化计划得以维持。同时引入了惩罚，即每第十次反应后会有短暂的电击。最初的惩罚强度对反应没有持久的影响。然后，随着电击强度的增加，可变比率的反应率比可变间隔的反应率更快地受到抑制。当电击强度降低时，可变间隔的反应恢复得更快，但两种情况下的反应率最终都回到了惩罚前的水平。在第二项实验中，在另外三只鸽子中研究了以下条件：（1）在每种电击强度的多个疗程中，逐渐增加和减少惩罚电击强度，同时通过多种可变比率、固定比率的食物强化计划维持反应；（2）如上所述，在可变比率或固定比率计划维持反应的情况下，改变惩罚电击强度，并在交替的日子呈现；（3）通过多个可变比率、固定比率的强化计划，在每个疗程中改变电击强度。在特定的电击强度下，两种方案下的反应都受到了大致相同程度的抑制。此外，在固定比率方案下，由于反应抑制的增加，强化后的停顿时间增加。
