Inferring the structure of latent class

Present optimization techniques in latent class analysis apply the expectation maximization algorithm or the Newton-Raphson algorithm for optimizing the parameter values of a prespecified model. These techniques can be used to find maximum likelihood estimates of the parameters, given the specified structure of the model, which is defined by the number of classes and, possibly, fixation and equality constraints. The model structure is usually chosen on theoretical grounds. A large variety of structurally different latent class models can be compared using goodness-of-fit indices of the chi-square family, Akaike’s information criterion, the Bayesian information criterion, and various other statistics. However, finding the optimal structure for a given goodness-of-fit index often requires a lengthy search in which all kinds of model structures are tested. Moreover, solutions may depend on the choice of initial values for the parameters. This article presents a new method by which one can simultaneously infer the model structure from the data and optimize the parameter values. The method consists of a genetic algorithm in which any goodness-of-fit index can be used as a fitness criterion. In a number of test cases in which data sets from the literature were used, it is shown that this method provides models that fit equally well as or better than the models suggested in the original articles.     

Relating distinctive orthographic and phonological processes to episodic memory performance

Three experiments examined the role of three distinctive perceptual factors in recognition and recall memory. Using a subject-paced presentation rate, the first two experiments (recognition and recall) examined (1) the number of phonological-to-orthographic neighbors, (2) phonological-to-orthographic consistency, and (3) orthographic-to-phonological consistency. The third experiment (recall) reexamined the number of phonological-to-orthographic neighbors, using an experimenter-paced presentation rate of 2 sec per item. In both recognition and recall memory tasks, the number of phonological-to-orthographic neighbors influenced memory performance, whereas the two types of consistency did not. The results indicate that having fewer phonological-to-orthographic neighbors (i.e., having distinct mappings between orthography and phonology, and between phonology and orthography, e.g., pulp) relieve words from interference in episodic memory tests for such words. Furthermore, words that are indistinct in terms of these mappings (e.g., tuck) are subject to interference from words with similar representations (e.g., luck, buck, stuck), and this weakens the memory trace for a particular word.     

When the presence of creative coworkers is related to creativity: role of supervisor close monitoring,developmental feedback,and creative personality

Study 1 was conducted to examine the contribution of the joint condition of supervisor close monitoring and the presence of creative coworkers to employees' creativity. In addition to replicating Study 1's results, Study 2 examined (a) the joint condition of supervisor developmental feedback and presence of creative coworkers and (b) whether creative personality moderated the contributions of the 2 joint conditions. Converging results from the 2 field studies demonstrated that when creative coworkers were present, the less supervisors engaged in close monitoring, the more employees exhibited creativity. Study 2 also found that the contribution of this joint condition was stronger for employees with less creative personalities and that when creative coworkers were present, the more supervisors provided developmental feedback, the more employees exhibited creativity.     

What response times tell of children's behavior on the balance scale task

Analysis of accuracy of responses to balance scale problems gives a global idea of the cognitive processes that underlie problem-solving behavior on this task. We show that response times (RTs) provide additional detailed information about the kind and duration of these processes. We derive predictions about the RTs from Siegler's (1981) model for the balance scale task, including the counterintuitive prediction that young adults are slower than children in solving particular balance scale problems. The predictions were tested in a study in which 191 6- to 22-year-old participants were presented with a computerized balance scale task. RTs were analyzed with regression models. In addition to qualitative differences between items, we also modeled quantitative differences between items in the regression models. Analyses supported the predictions and provided additional knowledge on the rules. Rule II was reformulated as a rule that always involves the encoding, but not always the correct application of the distance cue. RTs provided evidence for the use of a buggy-rule and not an addition-rule. Finally, a relation between rule inconsistency and increased RT was found.     

对人眼色觉异常的定量测量研究

依据Ｒａｙｌｅｉｇｈ颜色匹配方法研制人眼颜色视觉定量测量实验装置,并对２０名色觉正常和３０名色觉异常大学生的颜色视觉进行测量。结果表明,色觉异常被试在Ｒａｙｌｅｉｇｈ匹配中点和匹配范围测量值上均与色觉正常被试者存在明显的差异。     

FOK判断等级及其准确性的实验研究

通过实验集中探讨了FOK判断等级及其准确性的影响因素。实验以中文字串为学习材料,使用组内设计的实验方法研究了被激活信息的量和强度对FOK等级及准确性的影响。实验结果表明：FOK判断的等级是由被激活信息的总量决定的,和被激活信息的正确与否无关;FOK判断的准确性是由被激活信息的强度决定的;且二者之间是有内在联系的。     

耳科学的发展与展望

耳科学在人类与耳部疾病的斗争中兴起了１９世纪,在本世纪随科学技术的发展而获得迅速发展,特别是抗菌素和手术显微镜的出现,使耳显同外科技术不断提高,不仅能彻底地祛除耳部感染,而且可以有效地提高听力,耳科学家在聋病的治疗过程中,已能够有效地治疗传导性耳聋,但仍面临着治疗神经性耳聋的挑战,在现代科学技术革命的推动下,随着分析子生物学,细胞生物学等新技术的发展,在２１世纪,人类必定能够彻底治疗聋病。     

论中西医结合的过程与层次

中西医结合是一个长期困扰人们的难题。中医理论研究人体外部现象的变化规律,以古代哲学思想为指导,具有整体联系、动态把握的合理内核。而目前现代医学对人体结构和功能的认识,并不能完全揭示生命现象本质,因而也不能完全解释中医现象。这种认识有一个不断发展和深化的过程,自然辩证法观点认为层次越低、结合越紧密。分子导次是具有生物意义的最低层次。人类“基因组”计划的实现可能在一个新的高度阐明人体本质,也使中医现象     

汉字词识别过程的形,音,义编码作用的研究

本文通过两个实验,采用汉字词形、音、义特征匹配任务,探讨了影响汉字词的形、音、义编码与提取方式的有关因素。实验一发现在速示条件下,对汉字词再认的成绩并不受字词的使用度的影响,反应时无明显变化,而主要受编码加工的深度影响。在形、音、义特征加工中,对音码的加工时间最长,再认的正确率最低;义码的加工时间较短,再认正确率最高;形码的反应时及再认成绩介于音码与义码之间。实验二在非速示条件下也获得了相同的结果。研究结果表明,在汉字词的形、音、义特征中,存在着编码加工深度的差异。