Escape from serial stimuli leading to food

If the functional relations governing the strength of a conditioned reinforcer correspond to those obtained with other Pavlovian procedures (e.g., Kaplan, 1984), the termination of stimuli appearing early in the interval between successive food deliveries should be reinforcing. During initial training we presented four key colors, followed by food, in a recurrent sequence to each of 6 pigeons. This established a baseline level of autoshaped pecking. In later sessions, we terminated each of these colors or only the first color for a brief period following each peck, replacing the original color with a standard substitute to avoid darkening the key. Pecking decreased in the presence of the last color in the sequence but increased in the presence of the first. In accord with contemporary models of Pavlovian conditioning, these and other data suggest that the behavioral effects of stimuli in a chain may be better understood in terms of what each stimulus predicts, as measured by relative time to the terminal reinforcer, than in the exclusively positive terms of the traditional formulation (Skinner, 1938). The same model may also account for the initial pause under fixed-interval and fixed-ratio schedules of reinforcement.     

Number-word sequence skill and arithmetic performance

In two studies, the role of the number‐word sequence skill for arithmetic performance was investigated. In the first, children between 4 and 8 years of age were asked to count forward and backward on the number‐word sequence and to solve arithmetic problems followed by post‐solution interviews about solution procedures. The results demonstrated that the number‐word sequence skill predicted both number of problems solved and strategy to solve the problems. In Study 2 it was found that solving doubles (e.g., 2 + 2 = ?) problems served as a link between the number‐word sequence skill and the number of arithmetic problems solved. The findings suggest that counting on the number‐word sequence may be an early solution procedure and that, with increasing counting skill, the child may detect regularities in the number‐word sequence that can be used to form new and more accurate strategies for solving arithmetic problems.     

An estimating equations approach for the LISCOMP model

Maximum likelihood estimation is computationally infeasible for latent variable models involving multivariate categorical responses, in particular for the LISCOMP model. A three-stage generalized least squares approach introduced by Muthén (1983, 1984) can experience problems of instability, bias, non-convergence, and non-positive definiteness of weight matrices in situations of low prevalence, small sample size and large numbers of observed indicator variables. We propose a quadratic estimating equations approach that only requires specification of the first two moments. By performing simultaneous estimation of parameters, this method does not encounter the problems mentioned above and experiences gains in efficiency. Methods are compared through a numerical study and an application to a study of life-events and neurotic illness.The authors would like to thank Bengt Muthén for many helpful discussions and Scott Henderson for generously providing the Canberra data set. This work was supported in part by grant number GM49909 of the National Institutes of Health.     

Decomposition of a Rasch partial credit item into independent binary and indecomposable trinary items

For each Rasch (Masters) partial credit item, there exists a set of independent Rasch binary and indecomposable trinary items for which the sum of the scores and the partial credit score have identical probability density functions. If each indecomposable trinary item is further expressed as the sum of two binary items, then the binary items are positively dependent and cannot be both of the Rasch type. This paper was written while the author was working with Steve Ferrara and Hillary Michaels on some technical aspects of the Maryland School Performance Assessment Program. The author had been puzzled by the fact that most MSPAP assessment items have three or less score categories. With a psychometric justification now being apparent, this paper is dedicated to both of them.     

Learning argumentative capacities

In the fields of linguistics and psychology the didactic implementation of new knowledge relative to argumentative discourse and its acquisition has led us to develop a didactic sequence focused on the teaching of argumentation in 11–12 year old pupils. This sequence was experimented in six schools in order to assess the effect of these new educational methods on the capacities of pupils to treat the dialogic dimensions of argumentation in the writing of monologues. An analysis of the productions of the puils who had been submitted to the didactic sequence, compared with those of a control group, showed a significant improvement in the capacities of the first group. These improvements concerned aspects such as backing up arguments, acknowledging the addressee, negotiating with an eventual contradictor and using of a certain number of units and linguistic expressions t specific to argumentative texts (expressions of responsability taking, textual organisers of cause and conclusion, modalisations of probability and of certitude, concessions and polite expressions).     

内隐序列学习表征方式的实验研究

采用Lewicki等人创造的“矩阵扫描”任务,对内隐序列学习的表征方式进行了研究。结果发现：规则试验的反应时显著低于随机试验,说明被试能够内隐地掌握复杂规则,没有证据表明这与“运动”频率的大小和序列样例的记忆有关;此外,序列结构也是影响内隐序列学习的因素之一。     

序列学习是否是内隐学习？

序列学习是继人工语法之后内隐学习的另一研究范式。以往观点认为,在练习后,被试对规则刺激和随机刺激在反应时上出现差异,就表明被试是内隐学习,这种差异量就是内隐学习量。但现在很多学者对序列学习是否内隐这一问题提出了疑问;运用新方法（过程分离法,简称PDP）的研究发现,序列学习是否内隐同反应-刺激间隔（RSI）有关,当RSI = 0时,序列学习才是内隐的;根据RSI提出了神经网络模型。     

中西方思维方式的文化差异研究——二元对立与连续统合的视角

目的:验证中西方在思维方式上存在二元对立与连续统合的差异。方法:通过自编的中西方思维特征问卷,对中国学生47名,以及西方留学生及访问学者43名施测,收回有效问卷中国被试34名,西方被试32名。结果:中西方在思维方式上存在着显著差异,思维方式不存在性别差异。结论:中国人的思维方式是倾向于连续统合的,而西方人的思维方式是倾向于二元对立的。     

Nucleation and growth of crystals at the intermediate stage of phase transformations in binary melts

An exact analytical solution of integro-differential equations, which describe the phase transitions in supercooled binary melts, is constructed with allowance for fluctuating rates of crystal growth. A complete solution of the corresponding Fokker–Planck and balance equations is found for arbitrary nucleation kinetics and growth rates of crystals. In limiting cases, the obtained solutions transform to earlier known solutions for a special form of diffusivity in the space of crystal sizes and purely kinetic and “diffusion-kinetic” growth rates of nuclei.