Human observing: maintained by negative informative stimuli only if correlated with improvement in response efficiency.

Two experiments investigated the effect of observing responses that enabled college students to emit more efficient distributions of reinforced responses. In Experiment 1, the gains of response efficiency enabled by observing were minimized through use of identical low-effort response requirements in two alternating variable-interval schedules. These comprised a mixed schedule of reinforcement; they differed in the number of money-backed points per reinforcer. In each of three choices between two stimuli that varied in their correlation with the variable-interval schedules, the results showed that subjects preferred stimuli that were correlated with the larger average amount of reinforcement. This is consistent with a conditioned-reinforcement hypothesis. Negative informative stimuli--that is, stimuli correlated with the smaller of two rewards--did not maintain as much observing as stimuli that were uncorrelated with amount of reward. In Experiment 2, savings in effort made possible by producing S- were varied within subjects by alternately removing and reinstating the response-reinforcement contingency in a mixed variable-interval/extinction schedule of reinforcement. Preference for an uncorrelated stimulus compared to a negative informative stimulus (S-) decreased for each of six subjects, and usually reversed when observing permitted a more efficient temporal distribution of the responses required for reinforcement; in this case, the responses were pulls on a relatively high-effort plunger. When observing the S- could not improve response efficiency, subjects again chose the control stimulus. All of these results were inconsistent with the uncertainty-reduction hypothesis.     

Choice: A local analysis

Analyses of free-operant choice usually employ one of two general procedures: the simple concurrent procedure (i.e., a concurrent variable-interval variable-interval schedule) or the concurrent-chains procedure (i.e., concurrently available initial links, each leading to an exclusively available terminal link). Theories about choice usually focus on only one of the two procedures. For example, maximization theories, which assert that behavior is distributed between two alternatives in such a way that overall rate of reinforcement is maximized, have been applied only to the simple concurrent procedure. In the present paper, a form of the pairing hypothesis (according to which pairings between one stimulus and another affect the value of the first, and pairings between responses and reinforcers affect the value of the former) is developed in a way that allows it to make qualitative predictions with regard to choice in a variety of simple concurrent and concurrent-chains procedures. The predictions include matching on concurrent variable-interval variable-interval schedules, preference reversal in the self-control paradigm, and preference for tandem over chained terminal links.     

Resistance to change and relapse of observing

Four experiments examined relapse of extinguished observing behavior of pigeons using a two-component multiple schedule of observing-response procedures. In both components, unsignaled periods of variable-interval (VI) food reinforcement alternated with extinction and observing responses produced stimuli associated with the availability of the VI schedule (i.e., S+). The components differed in the rate of food arranged (Rich = VI 30 s; Lean = VI 120 s). In Experiment 1, following baseline training, extinction of observing involved removal of both food and S+ deliveries, and reinstatement was examined by presenting either response-independent food or S+ deliveries. In Experiment 2, extinction involved removal of only food deliveries while observing responses continued to produce S+. Reinstatement was examined by delivering food contingent upon the first two food-key responses occurring in the presence of the S+. Experiment 3 assessed ABA renewal of observing by extinguishing food-key and observing responses in the presence of one contextual stimulus (i.e., B) and then returning to the original training context (i.e., A) during continued extinction. Experiment 4 examined resurgence by introducing food reinforcement for an alternative response during extinction, and subsequently removing that alternative source of food. Across experiments, relative resistance to extinction and relapse of observing tended to be greater in the component previously associated with the higher rate of primary reinforcement. Relapse of observing or attending to stimuli associated with primary reinforcement appears to be impacted by frequency of primary reinforcement in a manner similar to responding maintained directly by primary reinforcement.     

胸腺五肽在中毒患者治疗中疗效观察

观察胸腺五肽在中毒患者治疗中的效果.选取ICU中毒患者共40例.分为试验组和对照组,试验组23例,对照组17例.试验组在基础治疗同时加用胸腺五肽,对照组只对症治疗.观察比较两组患者D1、3、5、7天的体温、白细胞计数、中性粒细胞计数、呼吸机辅助呼吸时间、镇静镇痛药物应用时间、C反应蛋白水平、病原学结果.两组D1体温、白细胞计数、中性粒细胞计数和CRP指标比较,差异无统计学意义(P＞0.05);在治疗D3、D5和D7两组白细胞计数比较,在治疗D3和D5两组中性粒细胞计数比较,在治疗D5和D7两组体温比较,在治疗D5两组CRP比较,差异有统计学意义(均P＜0.05).试验组应用呼吸机辅助呼吸时间短于对照组,差异有统计学意义(P＜0.001).试验组发生相关性感染例数少于对照组,差异有统计学意义(P＜0.05).胸腺五肽在中毒患者治疗的应用中,可调节患者细胞免疫功能,减轻炎症活动,联合应用并未增加药物副反应,并能最终改善预后.     

孕激素在孕期治疗的利与弊

妊娠期间的内分泌变化是胎儿和胎盘发育的一个体现,尤其是孕激素在妊娠期和分娩期均发挥了重要的作用。但应注意孕期应用孕激素有利亦有弊,因此应从辩证的观点了解孕激素作为药物在临床治疗中的两重性,发挥其优点、克服其缺点,实现其治疗的最大效能。     

条件性的关联学习和消退过程的性别差异

采用事件相关电位技术和条件性关联学习模型相结合的方法, 考察在负性背景下男女性对一般事件的关联学习和消退是否存在差异。结果表明：在关联学习阶段, 男性较女性表现出P2潜伏期缩短和N2波幅增大, 而女性比男性表现出更大的P3波幅。在消退阶段, 女性较男性出现更小的P2波幅和更大的P3/LPP波幅。这说明女性可能慢于男性探索到条件刺激和非条件刺激之间的关联, 并且保持时间更久; 男性在相对早期对消退产生更大的反应, 女性则在相对晚期对消退投入更多的资源及努力。     

从基因疫苗的研究进展谈科学技术"双刃剑"

基因疫苗可以利用宿主细胞的蛋白合成系统合成目的抗原,诱导机体产生针对该抗原的体液和细胞免疫应答,具有安全性高和诱导全面免疫应答的能力,在肿瘤和病毒性疚病中具有良好的应用前景;但基因疫苗的潜在危险不容忽视,提高其疗效、减轻其副作用成为疫苗研制的重要方向.     

Stopping points: ‘I’, immunity and the real guarantee

Abstract

The aim of the paper is to bring out exactly what makes first-personal (and more generally indexical and demonstrative) contents special, by showing that they perform a distinctive cognitive function. Namely, they are stopping points of inquiry. First, I articulate this idea and then I use it to clear the ground from a troublesome conflation. That is, the conflation of this particular function all first-person thoughts have with the property of immunity to error through misidentification, which only some I-thoughts enjoy. Afterward, I show the implications of this idea for a theory of first-person content and of immunity to error though misidentification. I then make some comparisons with Pryor’s notion of wh-misidentification and immunity thereof and with Cappelen and Dever’s position on immunity to error through misidentification and show why they are defective.