Tail-measurability in monotone latent variable models

We consider latent variable models for an infinite sequence (or universe) of manifest (observable) variables that may be discrete, continuous or some combination of these. The main theorem is a general characterization by empirical conditions of when it is possible to construct latent variable models that satisfy unidimensionality, monotonicity, conditional independence, andtail-measurability. Tail-measurability means that the latent variable can be estimated consistently from the sequence of manifest variables even though an arbitrary finite subsequence has been removed. The characterizing,necessary and sufficient, conditions that the manifest variables must satisfy for these models are conditional association and vanishing conditional dependence (as one conditions upon successively more other manifest variables). Our main theorem considerably generalizes and sharpens earlier results of Ellis and van den Wollenberg (1993), Holland and Rosenbaum (1986), and Junker (1993). It is also related to the work of Stout (1990).The main theorem is preceded by many results for latent variable modelsin general—not necessarily unidimensional and monotone. They pertain to the uniqueness of latent variables and are connected with the conditional independence theorem of Suppes and Zanotti (1981). We discuss new definitions of the concepts of true-score and subpopulation, which generalize these notions from the stochastic subject, random sampling, and domain sampling formulations of latent variable models (e.g., Holland, 1990; Lord & Novick, 1968). These definitions do not require the a priori specification of a latent variable model.The authors made equivalent contributions to the results of this article. Ellis' research was supported by the Dutch Interuniversitary Graduate School of Psychometrics and Sociometrics. Junker's research was supported by ONR Grant N00014-87-K-0277, NIMH Grant MH15758, and a Carnegie Mellon University Faculty Development Grant. In addition Junker would like to acknowledge the hospitality of the Nijmegen Institute for Cognition and Information during his visit to the University of Nijmegen in August 5–10, 1993.     

Trace autoshaping: Acquisition, maintenance, and path dependence at long trace intervals

The pigeon's tendency to acquire and maintain signal-directed key pecking under a trace conditioning procedure was parametrically examined. In Experiment 1, the percentage of CS trials with a key peck response was a decreasing function of the trace interval for separate groups of pigeons. The majority of subjects acquired signal-directed key pecking with trace intervals as long as 36 sec. In Experiment 2, differential maintenance of key pecking occurred across trace intervals in a within-subject procedure. Maintenance of key pecking at 36- and 60-sec trace intervals was path dependent in that responding depended on the subject's performance under the preceding trace interval.     

Pharmacotherapy of schizophrenia and affective disorders: Behavioral assessment of psychiatric medications

Objectively defined, publicly observable ward behaviors (body activity, extremity activity, scanning, social interaction, proximity, participation, laughing/smiling, and idiosyncratic behavior) emitted by psychiatric inpatients with either schizophrenic or affective disorders were time sampled both before and during the administration of psychiatric medications (neuroleptics, tricyclics, and lithium). The data indicate that the primary effects of the pharmacological interventions are confined to activity measures and symptoms rather than social behaviors. The implications of these results for treatment protocols are discussed in terms of interactions between pharmacological and psychosocial interventions. In addition, rates of behavior during treatment were related to baseline rates via a log-log function of negative slope, a result that is consistent with data derived from the infrahuman laboratories. Taken together the results provide support for attempts to relate preclinical and clinical psychopharmacology and suggest that behavioral assessment can be applied profitably to drug effects in clinical situations.These investigations were supported in part by State of Illinois Department of Mental Health and Developmental Disabilities Grants RD836-13 and RD622-02 to the first author. The cooperation of the Illinois State Psychiatric Institute staff is gratefully acknowledged. Assistance in data collection was provided by S. Sussman and K. Mueser.     

Pharmacological and Behavioral Strategies for Smoking Cessation

After over two decades of intensive research, a variety of smoking cessation strategies, both behavioral and pharmacotherapeutic, have been developed and clinically validated. In this review, pharmacological products available for smoking cessation are profiled and examined for efficacy. Results of a recent comprehensive review and meta-analysis by the Agency for Health Care Policy and Research on the effects of behavior therapy on smoking cessation are also discussed. Further, meta-analyses and studies exploring the important interaction between pharmacological and behavioral therapies are considered. Applications of the growing wealth of smoking cessation strategies are discussed with respect to the needs of some special subpopulations of smokers including highly nicotine-dependent smokers and smokers with comorbid psychiatric diagnoses.     

Source dependence in the valuation of objects

We ran two experiments to test whether people value objects more highly when they obtain those objects due to exemplary performance at a task. In the first, subjects who believed they had obtained a prize due to their performance on a classroom exercise valued it more highly than those who believed they had obtained it by chance. In the second, subjects who obtained a prize due to exemplary performance on a task valued it more highly than those who obtained it due to their poor performance. In both experiments, this ‘source dependence’ effect is approximately equal in strength to the endowment effect, which compares the valuation of subjects with and without the prize. We suggest a possible explanation for this source-dependence effect based on associationism, and rule out two alternative explanations.     

冲动性对不同成瘾行为发展的调控及其神经机制

近年来越来越多的研究证据提示, 个体冲动性在成瘾疾患发生发展机制中具有关键作用, 可能成为成瘾行为的潜在易感标记以及早期识别和干预的重要靶点, 但冲动性对不同成瘾行为变化发展的调控机制尚不明确。项目拟综合跨成瘾谱系比较、纵向追踪设计、冲动行为干预等研究途径, 采用人格测量、神经认知、神经影像等技术, 首先比较尼古丁依赖者与网络游戏成瘾者的冲动性结构及其在前额叶–纹状体环路的结构功能改变; 然后采用混合分组设计筛选出具有高低冲动性的非成瘾青少年进行连续追踪研究, 考察冲动性对尼古丁依赖与网络游戏成瘾的预测效力; 并采用认知行为训练, 对吸烟成瘾者与网络游戏成瘾者进行冲动干预, 考察行为干预对冲动性水平及前额叶–纹状体环路功能的改变, 以及对不同成瘾行为发展的抑制后效。旨在探索冲动性作为成瘾的潜在易感标记及干预靶点的效力。     

大学生手机互联网依赖对疏离感的影响：社会支持系统的作用

为探讨大学生手机依赖、现实社会支持、网络社会支持及疏离感的关系。采用大学生手机成瘾倾向量表、青少年疏离感量表、大学生网络社会支持量表和青少年社会支持量表对442 名大学生进行测量。结果发现：（1）不同手机依赖水平与疏离感差异显著,高手机依赖者的疏离感均显著高于低手机依赖者;（2）手机依赖对疏离感有显著正向预测作用,网络社会支持和现实社会支持对疏离感有显著负向预测作用;（3）现实社会支持在手机依赖与疏离感间具有中介效应和调节效应,手机依赖既直接对疏离感产生影响,又通过现实社会支持对疏离感产生影响,中介效应占总效应的比例为17.8%;（4）现实社会支持和网络社会支持在手机依赖与疏离感间均具有调节效应,可以缓冲手机依赖对疏离感的影响。     

海洛因依赖者抑制控制功能的损伤机制及其可逆性

抑制控制障碍是海洛因依赖者认知功能受损的核心问题, 是影响复吸的关键因素。大量研究证实了海洛因依赖者抑制控制功能的受损, 并且发现长期药物滥用者额叶、前扣带回皮层、中脑腹侧被盖区、伏隔核、脑岛等相关脑区活动存在异常。以往研究表明海洛因依赖者抑制控制功能受损是一种持久性的、不可逆的脑损伤, 但最近一些研究却提供了毒品戒断者抑制控制功能生物性恢复的证据。未来的研究应该更加关注多重冲突条件下海洛因依赖者抑制控制功能的研究, 并且在戒毒实践中根据海洛因戒断者自身特点进行区分性治疗。     

海洛因成瘾者复吸倾向的研究

目的：探讨海洛因成瘾者复吸倾向的影响因素。方法：采用“复吸倾向问卷”对289名戒毒劳教人员进行测评。结果：发现戒毒意愿、将来环境、身心状态、物质替代和社会支持是影响复吸倾向的五个因素。这个结果提示在海洛因成瘾者的康复治疗中应该采用“药物——心理——社会”模式。