Bayesian IRT Guessing Models for Partial Guessing Behaviors

According to the recent Nation’s Report Card, 12th-graders failed to produce gains on the 2005 National Assessment of Educational Progress (NAEP) despite earning better grades on average. One possible explanation is that 12th-graders were not motivated taking the NAEP, which is a low-stakes test. We develop three Bayesian IRT mixture models to describe the results from a group of examinees including both nonguessers and partial guessers. The first assumes that the guesser answers questions based on his or her knowledge up to a certain test item, and guesses thereafter. The second model assumes that the guesser answers relatively easy questions based on his or her knowledge and guesses randomly on the remaining items. The third is constructed to describe more general low-motivation behavior. It assumes that the guesser gives less and less effort as he or she proceeds through the test. The models can provide not only consistent estimates of IRT parameters but also estimates of each examinee’s nonguesser/guesser status and degree of guessing behavior. We show results of a simulation study comparing the performance of the three guessing models to the 2PL-IRT model. Finally, an analysis of real data from a low-stakes test administered to university students is presented.     

猜谜作业中顿悟的ERP效应

采用事件相关电位(ERP)探索问题解决过程中顿悟的神经机制。以猜谜作业为实验程序,对“有顿悟”和“无顿悟”答案引发的脑电分别进行叠加和平均,并将二者相减（有顿悟-无顿悟）得到差异波。在250~500 ms “有顿悟”比“无顿悟”的ERP波形有一个更加负性的偏移,在差异波中,这个负成分的潜伏期约为380 ms（N380）。地形图和电流密度图显示,N380在额中央区活动最强。偶极子源定位分析结果显示,N380可能起源于扣带前回。因此,N380可能反映顿悟问题解决过程中思维定势的突破。     

Uninstructed human responding: Sensitivity of low-rate performance to schedule contingencies

College students' presses on a telegraph key occasionally turned on a light in the presence of which button presses produced points later exchangeable for money. Initially, responding was maintained by low-rate contingencies superimposed on either random-interval or random-ratio schedules. Later, the low-rate contingencies were relaxed. Low-rate key pressing had been established for some students by shaping and for others by demonstration and written instructions. After the low-rate contingencies were relaxed, higher response rates generally did not increase point earnings with random-interval scheduling, but did so with random-ratio scheduling. In both cases, shaped responding usually increased, and instructed responding usually continued at an unchanged low rate. The insensitivity of instructed responding typically occurred despite contact with the contingencies. The differential sensitivity to schedule contingencies of shaped responding relative to instructed responding is consistent with the different properties of contingency-governed and rule-governed behavior and is not rate-dependent.     

A note on keats' generalization of the rasch model

An alternative derivation is given for a simple test model which incorporates anability parameter for the subject anddifficulty level andguessing parameters for the problem. The probability of a correct response to the problem is a projective transformation of the problem difficulty. The ability and difficulty parameters separate into additive components.     

Items bundles

An item bundle is a small group of multiple choice items that share a common reading passage or graph, or a small group of matching items that share distractors. Item bundles are easily identified by paging through a copy of a test. Bundled items may violate the latent conditional independence assumption of unidimensional item response theory (IRT), but such a violation would not typically suggest the existence of a new fundamental human ability to read one specific reading passage or to interpret one specific graph. It is important, therefore, to have theoretical concepts and empirical checks that distinguish between, on the one hand, anticipated violations of latent conditional independence within item bundles, and, on the other hand, violations that cannot be attributed to idiosyncratic features of test format and instead suggest departures from unidimensionalty. To this end, two theorems on unidimensional IRT are extended to describe observable item response distributions when there is conditional independencebetween but not necessarilywithin item bundles.The author is grateful to Ivo Molenaar and the referees for many helpful suggestions, and to D. Thayer for assistance with computing.     

A model for repeat paired comparison preference tests

A model is proposed that describes subject behavior on repeat paired comparison preference tests. The model extends prior work in this area in that it explicitly allows for abstentions and permits the derivation of individual true scores for discrimination ability as well as conditional estimates of proportionate preference. With these results, the properties of a paired comparison test can be thoroughly explored. An empirical example is presented, and test design issues are considered. In particular, repeat paired comparison preference tests are shown to be inherently less efficient discrimination tests than are pick 1 of 2 tests.     

Learning phonology with substantive bias: an experimental and computational study of velar palatalization

There is an active debate within the field of phonology concerning the cognitive status of substantive phonetic factors such as ease of articulation and perceptual distinctiveness. A new framework is proposed in which substance acts as a bias, or prior, on phonological learning. Two experiments tested this framework with a method in which participants are first provided highly impoverished evidence of a new phonological pattern, and then tested on how they extend this pattern to novel contexts and novel sounds. Participants were found to generalize velar palatalization (e.g., the change from [k] as in keep to [t⌢∫S] as in cheap) in a way that accords with linguistic typology, and that is predicted by a cognitive bias in favor of changes that relate perceptually similar sounds. Velar palatalization was extended from the mid front vowel context (i.e., before [e] as in cape) to the high front vowel context (i.e., before [i] as in keep), but not vice versa. The key explanatory notion of perceptual similarity is quantified with a psychological model of categorization, and the substantively biased framework is formalized as a conditional random field. Implications of these results for the debate on substance, theories of phonological generalization, and the formalization of similarity are discussed.     

Enhancing Creativity With Combined Transcranial Direct Current and Random Noise Stimulation of the Left Dorsolateral Prefrontal Cortex and Inferior Frontal Gyrus

Creativity is a fundamental human accomplishment from scientific advances to composing music. The left dorsolateral prefrontal cortex (DLPFC) and inferior frontal gyrus (IFG) are important metacontrol hubs in flexibility and persistence brain states, respectively. Those hubs are related to divergent thinking, insight problem-solving, and convergent thinking. In this double-blind, between-subjects study, 81 healthy participants were randomly assigned to one of three groups (n = 27) that received a combined transcranial direct current stimulation–transcranial random noise stimulation (tDCS-tRNS) protocol with the anode over the left DLPFC and cathode over the left IFG (+DLPFC−IFG), the opposite montage (−DLPFC+IFG), and a sham group (+DLPFC−IFG). Both active tDCS-tRNS groups received 20 min of 1 mA tDCS with 1 mA (100–500 Hz) tRNS. Creativity was assessed before (baseline) and during stimulation with the Unusual Uses, Picture Completion (PC), Remote Association test (RAT), Matchstick Arithmetic (MA), and Nine-dot (ND) problems. Only the +DLPFC−IFG group had significantly higher scores compared with sham in the RAT (p = .009), PC fluency (p = .018), PC originality (p = .007), ND (p = .007), and MA (p = .032). Overall, −DLPFC+IFG had greater scores in all creativity tests compared with sham. Implications from the metacontrol theory are discussed.     

Modelling partially cross‐classified multilevel data

This article proposes an approach to modelling partially cross‐classified multilevel data where some of the level‐1 observations are nested in one random factor and some are cross‐classified by two random factors. Comparisons between a proposed approach to two other commonly used approaches which treat the partially cross‐classified data as either fully nested or fully cross‐classified are completed with a simulation study. Results show that the proposed approach demonstrates desirable performance in terms of parameter estimates and statistical inferences. Both the fully nested model and the fully cross‐classified model suffer from biased estimates of some variance components and statistical inferences of some fixed effects. Results also indicate that the proposed model is robust against cluster size imbalance.     

考试评分缺失数据的概化理论分析

考试评分缺失数据较为常见,如何有效利用现有数据进行统计分析是个关键性问题。在考试评分中,题目与评分者对试卷得分的影响不容忽视。根据概化理论原理,按考试评分规则推导出含有缺失数据双侧面交叉设计（p×i×r）方差分量估计公式,用Matlab7.0软件模拟多组缺失数据,验证此公式的有效性。结果发现：（1）推导出的公式较为可靠,估计缺失数据的方差分量偏差相对较小,即便数据缺失率达到50％以上,公式仍能对方差分量进行较为准确地估计;（2）题目数量对概化理论缺失数据方差分量的估计影响最大,评分者次之,当题目和评价者数量分别为6和5时,公式能够趋于稳定地估计;（3）学生数量对各方差分量的估计影响较小,无论是小规模考试还是大规模考试,概化理论估计缺失数据的多个方差分量结果相差不大。