BRETHOWER D M, REYNOLDS G S
J Exp Anal Behav. 1962 Apr;5(2):191-9. doi: 10.1901/jeab.1962.5-191.
The key pecking of two pigeons was reinforced on a variable-interval schedule of reinforcement during the presentation of each of two stimuli. In various phases of the experiment, punishment followed every response emitted in the presence of one of the stimuli. In general, when the rate of punished responding changed during the presentation of one stimulus, the rate of unpunished responding during the other stimulus changed in the opposite direction. This sort of change in rate is an example of behavioral contrast. When punishment was introduced, the rate of punished responding decreased and the rate of unpunished responding increased as functions of shock intensity. When the rate of previously punished responding increased after the termination of the shock, the rate of the always unpunished responding decreased. When the procedure correlated with a red key was changed from variable-interval reinforcement and punishment for each response to extinction and no punishment, the rate of reinforced responding during presentations of a green key decreased and then increased while the rate of the previously punished responding during red first increased and then decreased during extinction.
在呈现两种刺激中的每一种时，两只鸽子的关键啄击行为按照可变间隔强化程序进行强化。在实验的不同阶段，在其中一种刺激出现时发出的每一个反应之后都会施加惩罚。一般来说，当在一种刺激呈现期间受惩罚反应的速率发生变化时，在另一种刺激期间未受惩罚反应的速率会朝相反方向变化。这种速率变化是行为对比的一个例子。当引入惩罚时，受惩罚反应的速率随着电击强度的变化而降低，未受惩罚反应的速率则增加。当电击终止后，先前受惩罚反应的速率增加时，一直未受惩罚反应的速率则降低。当与红色按键相关的程序从对每个反应进行可变间隔强化和惩罚改为消退且不惩罚时，在绿色按键呈现期间强化反应的速率先降低然后增加，而在红色按键呈现期间先前受惩罚反应的速率在消退期间先增加然后降低。
