Cross-modal transfer and intermediate-size transposition

Kindergarten and third grade boys learned an intermediate-size problem either visually or tactually. They were then tested either visually or tactually. The test sets were separated from the training set by either 1, 2, or 4 steps. The data supported predictions derived from the D. M. Lane and F. M. Rabinowitz (Child Development 1977,48, 412–426) transposition theory on choice and consistency measures. Of greatest interest were the markedly different transposition gradients exhibited by the boys in the visual-visual and visual-tactual groups.     

选择一致性影响结果评价的ERP研究

本研究通过两个实验探讨了当被试主动做出与他人一致/不一致的选择行为(实验1)或看到他人做出与自己一致/不一致的选择行为(实验2)时,其选择行为的一致性是如何影响结果评价过程的。脑电数据表明在结果评价的早期阶段,无论被试是主动或被动地与他人做出相同选择,这种选择一致性都会放大输赢结果之间的差异:体现在选择一致情况下比不一致情况下诱发更大的d FRN。而在结果评价的晚期阶段,当被试先做出选择之后,看到他人做出与自己不一致的选择时(实验2),相比他人与自己选择一致时,诱发了更大的P3和LPP波幅。说明被试很可能把他人的不一致选择加工为一种冲突。因此投入了更多认知资源来加工这一结果。本研究是一个探索性的创新研究,首次从时间维度上分离了选择行为和结果反馈两个阶段,并提供了选择一致性对结果评价有影响作用的脑电证据。     

The influence of perceptual and semantic categorization on inhibitory processing as measured by the N2–P3 response

In daily activities, humans must attend and respond to a range of important items and inhibit and not respond to unimportant distractions. Our current understanding of these processes is largely based on perceptually simple stimuli. This study investigates the interaction of conceptual-semantic categorization and inhibitory processing using Event Related Potentials (ERPs). Participants completed three Go–NoGo tasks that increased systematically in the degree of conceptual-semantic information necessary to respond correctly (from single items to categories of objects and animals). Findings indicate that the N2 response reflects inhibitory processing but does not change significantly with task difficulty. The P3 NoGo amplitude, on the other hand, is attenuated by task difficulty. Further, the latency of the peak of the P3 NoGo response elicited by the most difficult task is significantly later than are the peaks detected during performance of the other two tasks. Thus, the level of complexity of conceptual-semantic representations influences inhibitory processing in a systematic way. This inhibition paradigm may be a key for investigating inhibitory dysfunction in patient populations.     

The Local Minima Problem in Hierarchical Classes Analysis: An Evaluation of a Simulated Annealing Algorithm and Various Multistart Procedures

Hierarchical classes models are quasi-order retaining Boolean decomposition models for N-way N-mode binary data. To fit these models to data, rationally started alternating least squares (or, equivalently, alternating least absolute deviations) algorithms have been proposed. Extensive simulation studies showed that these algorithms succeed quite well in recovering the underlying truth but frequently end in a local minimum. In this paper we evaluate whether or not this local minimum problem can be mitigated by means of two common strategies for avoiding local minima in combinatorial data analysis: simulated annealing (SA) and use of a multistart procedure. In particular, we propose a generic SA algorithm for hierarchical classes analysis and three different types of random starts. The effectiveness of the SA algorithm and the random starts is evaluated by reanalyzing data sets of previous simulation studies. The reported results support the use of the proposed SA algorithm in combination with a random multistart procedure, regardless of the properties of the data set under study. Eva Ceulemans is a post-doctoral fellow of the Fund for Scientific Research Flanders (Belgium). Iwin Leenen is a post-doctoral researcher of the Spanish Ministerio de Educación y Ciencia (programa Ramón y Cajal). The research reported in this paper was partially supported by the Research Council of K.U. Leuven (GOA/05/04).