Divided attention and the matching law: Sample duration affects sensitivity to reinforcement allocation

Previously, we have shown that changes in pigeons’ divided attention performance resulting from changes in relative reinforcement are well described by the generalized matching law. In the present experiment, we examined whether sensitivity of performance to variations in relative reinforcement would be dependent upon sample duration. Pigeons responded on a delayed matching-to-sample procedure with compound samples (color 1 line orientation) and element comparison stimuli (two colors or two line orientations). Relative reinforcement for accurate matches on the two types of comparison trials varied across conditions. Sample duration was short (i.e., 0.75 sec) for half of the trials in a session and longer (i.e., 2.25 sec) for the other half. Sensitivity of accuracy to changes in relative reinforcement was greater with the longer sample than with the shorter sample, suggesting that differential reinforcement alters the allocation of attending to the elements of compound stimuli. Continued examination of the applicability of well-established theories of goal-directed behavior to the allocation of attention may provide further insights into what is variously referred to as goal-directed, voluntary, endogenous, or top-down control of attention.     

维吾尔族7—18岁城乡青少年身体形态比较

了解维吾尔族青少年身体形态状况、形态发育的变化特点及其变化规律,为改善维吾尔族青少年体质健康水平提供依据。采用专家访谈法、测试和数理统计法,于2012年10—12月,对新疆和田地区中小学7—18岁4800名维吾尔族青少年的身高、体重和胸围指标进行统计分析,并针对问题提出相关建议。     

基于亚马逊畅销书发行的网络发行渠道走向研究

网络发行渠道凭借其速度快、成本低、信息积累性强等优势,在当下的出版发行工作中扮演着越来越重要的角色.然而,随着数字时代的到来,图书消费者的阅读与消费习惯的转变从趋势成为事实,网络发行渠道应在购书渠道设置、营销信息形式、互动机制运用等方面,进一步融合网络平台的优势、融合纸质书与电子书的发行、融合多元的营销信息形式、融合多方互动机制,使图书发行工作更高效.亚马逊在这一方面的表现可供借鉴,它也表征着网络发行渠道进一步发展的新走向.     

论新时期党群关系建设方式的改革

党群关系建设方式的改革,紧迫而重要。党在以往党群关系建设方式上积累了丰富经验,但是相对于当前新形势和新的时代要求,党群关系建设方式亟需改革。因此,应以改革创新精神,大胆探索出新时期党群关系的建设路径。     

地方层级议会与政府的政治博弈--以民初奉天临时省议会弹劾周肇祥案为例

民国初年,奉天临时省议会进行政府部门财政核查时,发现盐运使周肇祥冒支公款问题,引出周挪用公款、私设账目、僭越司法、强占民妇、贿买差缺等一系列违法逾规行径。围绕周肇祥案,奉天临时省议会展开了一场控诉与反控诉的博弈。在奉天临时省议会力争之下,周肇祥最终被迫引退并离开奉天。这场议员与官僚的政治冲突中,民主派获得政治胜利,上演了民初地方议员与官员政治博弈中罕见一幕。奉天临时省议会弹劾周肇祥案是研究民初议会与政府关系在地方层级运作一个重要案例,揭示了民初中国民主政治发展的真实一面。     

Temporal integration and instrumental conditioned reinforcement

Stimuli associated with primary reinforcement for instrumental behavior are widely believed to acquire the capacity to function as conditioned reinforcers via Pavlovian conditioning. Some Pavlovian conditioning studies suggest that animals learn the important temporal relations between stimuli and integrate such temporal information over separate experiences to form a temporal map. The present experiment examined whether Pavlovian conditioning can establish a positive instrumental conditioned reinforcer through such temporal integration. Two groups of rats received either delay or trace appetitive conditioning in which a neutral stimulus predicted response-independent food deliveries (CS1→US). Both groups then experienced one session of backward second-order conditioning of the training CS1 and a novel CS2 (CS1–CS2 pairing). Finally, the ability of CS2 to function as a conditioned reinforcer for a new instrumental response (leverpressing) was assessed. Consistent with the previous demonstrations of temporal integration in fear conditioning, a CS2 previously trained in a trace-conditioning protocol served as a better instrumental conditioned reinforcer after backward second-order conditioning than did a CS2 previously trained in a delay protocol. These results suggest that an instrumental conditioned reinforcer can be established via temporal integration and raise challenges for existing quantitative accounts of instrumental conditioned reinforcement.