Effects of signals preceding and following shock on baseline responding during a conditioned-suppression procedure

Long-Evans rats were exposed to a succession of conditioned-suppression procedures involving pairings of (1) signal-shock, (2) shock-signal, and (3) a signal-shock-signal sequence in which first and second signals were at first physically identical. Traditional suppression of food-reinforced responding was obtained under the signal-shock arrangement, and exposure to the shock-signal sequence resulted in conditioned enhancement of responding during the signal. The signal-shock-signal condition reliably suppressed responding during the first signal, but produced no differential effect on response rate during the second signal. Baseline responding was least changed from preshock rates under the signal-shock-signal procedure, but baseline rate was considerably reduced under the signal-shock and shock-signal arrangements, the latter yielding most substantial reductions. A second experiment indicated that the magnitude and direction of changes in baseline responding reported in Experiment I were not confined to cases in which the first and second signals in the signal-shock-signal arrangement were physically identical. It is suggested that the major effects of the conditioned-suppression procedure on response rate might not be confined to presentations of the signal.     

Alternative response training, differential reinforcement of other behavior, and extinction in squirrel monkeys (Saimiri sciureus)

In Experiment I, (a) extinction, (b) extinction plus reinforcement of a discrete alternative response, and (c) differential reinforcement of other behavior were each correlated with a different stimulus in a three-component multiple schedule. The alternative-response procedure more rapidly and completely suppressed behavior than did differential reinforcement of other behavior. Differential reinforcement of other behavior was slightly more effective than extinction alone. In Experiment II, reinforcement of specific alternative behavior during extinction and differential reinforcement of other behavior were used in two components, while one component continued to provide reinforcement for the original response. Once again, the alternative-response procedure was most effective in reducing responding as long as it remained in effect. However, the responding partially recovered when reinforcement for competing behavior was discontinued. In general, responding was less readily reduced by differential reinforcement of other behavior than by the specific alternative-response procedure.     

雅斯贝尔斯的海德格尔批判:思维的傲慢

一、比较方法的意义与界限假定一个人严肃地对待哲学,那么任何试图比较卡尔.雅斯贝尔斯与马丁.海德格尔的作法都难免显得十分可疑。也许,甚至将比较方法列入哲学工具之标准目录也显得可疑,但是,那些使用这种方法的人们却常为这种方法所提供的巨大的解释收益而辩护。当然,对于我     

欧麦尔传略

先知穆罕默德归真后,在伊斯兰教旗帜下联合起来的阿拉伯人进入了一个新的发展时期。第一任哈里发艾布·伯克的功绩在于重新统一了阿拉伯半岛,并开拓了疆土。但艾布·伯克执政两年就归真了,继承这一伟大事业并使伊斯兰教发展成为一个国际性宗教的,是第二任哈里发欧麦尔。他为哈里发国家的巩固和发展做出了巨大的贡献。