McKearney J W
Science. 1968 Jun 14;160(3833):1249-51. doi: 10.1126/science.160.3833.1249.
Squirrel monkeys trained to respond under a schedule in which each response postponed the delivery of electric shock developed a steady rate of responding. When a schedule in which an electric shock was presented following the first response occurring after 10 minutes (10-minute fixed-interval schedule) was programed concurrently, there was little effect on the pattern of responding. When the shock-postponement schedule was eliminated, the fixed-interval schedule of shock-presentation maintained a pattern of positively accelerated responding that is characteristic of fixed-interval schedules of reinforcement.
经过训练在一种反应可推迟电击交付的程序下做出反应的松鼠猴，形成了稳定的反应速率。当同时安排一个在10分钟后首次出现反应就施加电击的程序（10分钟固定间隔程序）时，对反应模式几乎没有影响。当取消电击推迟程序后，电击呈现的固定间隔程序维持了一种正加速反应模式，这是固定间隔强化程序的特征。
