心理与教育测验中异常反应侦查新技术：变点分析法

变点分析法(change point analysis, CPA)近些年才引入心理与教育测量学, 相较于传统方法, CPA不仅可以侦查异常作答被试, 还能自动精确地定位变点位置, 高效清洗作答数据。其原理在于：判断作答序列中是否存在可将该序列划分为具有不同统计学属性两部分的点(即变点), 并且需使用被试拟合统计量(person-fit statistic, PFS)来量化两个子序列之间的差异。未来可将单变点分析拓展至多变点, 结合反应时等信息, 构建非参数化指标以及将现有指标拓展至多级计分或多维测验, 以提高CPA的适用广度及效力。     

医学科研或论文中常见的统计学问题

医学统计学在医学科研中占有重要地位,统计方法正确使用与否直接影响论文的结果和质量,但是具体使用过程中统计学方法或指标常常被混淆或使用不妥。本文就科研设计、数据描述、推演结论等方面容易混淆的统计学常见问题进行简要阐述,并举例分析可能出现误用的指标和方法,提高医务工作者对医学统计学的认识。     

A reanalysis of Lord’s statistical treatment of football numbers

Stevens’ theory of admissible statistics [Stevens, S. S. (1946). On the theory of scales of measurement. Science, 103, 677680] states that measurement levels should guide the choice of statistical test, such that the truth value of statements based on a statistical analysis remains invariant under admissible transformations of the data. Lord [Lord, F. M. (1953). On the statistical treatment of football numbers. American Psychologist, 8, 750-751] challenged this theory. In a thought experiment, a parametric test is performed on football numbers (identifying players: a nominal representation) to decide whether a sample from the machine issuing these numbers should be considered non-random. This is an apparently illegal test, since its outcomes are not invariant under admissible transformations for the nominal measurement level. Nevertheless, it results in a sensible conclusion: the number-issuing machine was tampered with. In the ensuing measurement-statistics debate Lord’s contribution has been influential, but has also led to much confusion. The present aim is to show that the thought experiment contains a serious flaw. First it is shown that the implicit assumption that the numbers are nominal is false. This disqualifies Lord’s argument as a valid counterexample to Stevens’ dictum. Second, it is argued that the football numbers do not represent just the nominal property of non-identity of the players; they also represent the amount of bias in the machine. It is a question about this property-not a property that relates to the identity of the football players-that the statistical test is concerned with. Therefore, only this property is relevant to Lord’s argument. We argue that the level of bias in the machine, indicated by the population mean, conforms to a bisymmetric structure, which means that it lies on an interval scale. In this light, Lord’s thought experiment-interpreted by many as a problematic counterexample to Stevens’ theory of admissible statistics-conforms perfectly to Stevens’ dictum.     

Nihilism,Nietzsche and the Doppelganger Problem

Nihilism, Nietzsche and the Doppelganger Problem Was Nietzsche a nihilist? Yes, because, like J. L. Mackie, he was an error-theorist about morality, including the elitist morality to which he himself subscribed. But he was variously a diagnostician, an opponent and a survivor of certain other kinds of nihilism. Schacht argues that Nietzsche cannot have been an error theorist, since meta-ethical nihilism is inconsistent with the moral commitment that Nietzsche displayed. Schacht’s exegetical argument parallels the substantive argument (advocated in recent years by Wright and Blackburn) that Mackie’s error theory can’t be true because if it were, we would have to give up morality or give up moralizing. I answer this argument with a little bit of help from Nietzsche. I then pose a problem, the Doppelganger Problem, for the meta-ethical nihilism that I attribute to Mackie and Nietzsche. (If A is a moral proposition then not-A is a moral proposition: hence not all moral propositions can be false.) I solve the problem by reformulating the error theory and also deal with a variant of the problem, the Reinforced Doppelganger, glancing at a famous paper of Ronald Dworkin’s. Thus, whatever its demerits, the error theory, is not self-refuting, nor does it require us to give up morality.     

认知诊断模型中项目水平模型比较统计量的健壮性

使用模拟研究方法比较了以往研究中提出的基于观察信息矩阵、三明治矩阵的Wald（分别表示为W_Obs、W_Sw）、似然比（Likelihood Ratio）统计量以及新提出的基于经验交叉相乘信息矩阵的Wald统计量（W_XPD）在模型——数据失拟条件下进行项目水平上模型比较时的表现。结果显示：（1）W_Sw的一类错误控制率有很强的健壮性。（2）W_XPD在Q矩阵错误设定的大多数条件下的表现优于W_Sw。结论：模型—数据拟合良好时可以使用W_Sw进行项目水平上的模型比较,当模型与数据失拟时W_XPD可能是更好的选择。     

Neural mechanism underlying self-controlled feedback on motor skill learning

The present study investigated the neural mechanisms of self-controlled (SC) feedback underlying its learning advantages. Forty-two participants, including 24 females (16.43 ± 2.61 years) and 18 males (17.56 ± 0.86 years), were randomly assigned to a SC or yoked (YK) group. The 6-key-pressing task with a goal movement time was adopted as the experimental task. The behavioral results showed that the SC group demonstrated superior performance in transfer; however, the differences in retention did not reach statistical significance. Event-related potential analyses revealed that the SC group exhibited larger post-stimulus and post-feedback P3 amplitudes than the YK group in the frontal regions; these amplitudes were larger in the YK group in the parietal regions. The post-response error positivity amplitude was found to be larger in the YK group than in the SC group. These results suggest that SC feedback may allow the learner to more actively process the task stimuli and feedback information, and contributes to enhancing the learner’s motivation and attachment to the task being practiced. The present study provides a neurophysiological explanation for why SC feedback is effective in learning a new motor skill.     

The effect of running speed on joint coupling coordination and its variability in recreational runners

The purpose of this study was to examine the effect of speed on coordination and its variability in running gait using vector coding analysis. Lower extremity kinematic data were collected for thirteen recreational runners while running at three different speeds in random order: preferred speed, 15% faster and 15% lower than preferred speed. A dynamical systems approach, using vector coding and circular statistics, were used to quantify coordination and its variability for selected hip-knee and knee-ankle joint couplings. The influence of running speed was calculated from the continuous data sets of the running cycle, allowing for the identification of time percentages where differences existed. Results indicate that increases in running speed produced moderate alterations in the frequency of movement patterns which were not enough to alter classification of coordination. No effects of speed on coordination variability were observed. This study has demonstrated that coordination and coordination variability is generally stable in the range of ±15% around of preferred speed in recreational runners.     

A visualization technique for Bayesian reasoning

We tested a method for solving Bayesian reasoning problems in terms of spatial relations as opposed to mathematical equations. Participants completed Bayesian problems in which they were given a prior probability and two conditional probabilities and were asked to report the posterior odds. After a pretraining phase in which participants completed problems with no instruction or external support, participants watched a video describing a visualization technique that used the length of bars to represent the probabilities provided in the problem. Participants then completed more problems with a chance to implement the technique by clicking interactive bars on the computer screen. Performance improved dramatically from the pretraining phase to the interactive‐bar phase. Participants maintained improved performance in transfer phases in which they were required to implement the visualization technique with either pencil‐and‐paper or no external medium. Accuracy levels for participants using the visualization technique were very similar to participants trained to solve the Bayes theorem equation. The results showed no evidence of learning across problems in the pretraining phase or for control participants who did not receive training, so the improved performance of participants using the visualization method could be uniquely attributed to the method itself. A classroom sample demonstrated that these benefits extend to instructional settings. The results show that people can quickly learn to perform Bayesian reasoning without using mathematical equations. We discuss ways that a spatial solution method can enhance classroom instruction on Bayesian inference and help students apply Bayesian reasoning in everyday settings.     

Error reframing: studying the promotion of an error management culture

In the organizational behaviour and organizational psychology literature, individual errors are considered either as sources of blame (error-prevention culture) or as sources of learning and something to be encouraged in order to promote innovation (error-management culture). While we can assume that a third perspective exists somewhere in between, error management is usually considered as the best solution. Yet scholars have tended to neglect the planned and directed transition from a pure error-prevention to an error-management culture. We thus examine to what extent and under what conditions an organization can culturally transform the representation of individual errors through its business leaders. To answer this question, we conducted a qualitative study on the case of a French insurance company. We portray a realistic image of the promotion of an error management culture, pointing out certain limitations and constraints, while nonetheless identifying some conditions for successful error reframing.     

Characterizing Human Expertise Using Computational Metrics of Feature Diagnosticity in a Pattern Matching Task

Forensic evidence often involves an evaluation of whether two impressions were made by the same source, such as whether a fingerprint from a crime scene has detail in agreement with an impression taken from a suspect. Human experts currently outperform computer‐based comparison systems, but the strength of the evidence exemplified by the observed detail in agreement must be evaluated against the possibility that some other individual may have created the crime scene impression. Therefore, the strongest evidence comes from features in agreement that are also not shared with other impressions from other individuals. We characterize the nature of human expertise by applying two extant metrics to the images used in a fingerprint recognition task and use eye gaze data from experts to both tune and validate the models. The Attention via Information Maximization (AIM) model (Bruce & Tsotsos, 2009) quantifies the rarity of regions in the fingerprints to determine diagnosticity for purposes of excluding alternative sources. The CoVar model (Karklin & Lewicki, 2009) captures relationships between low‐level features, mimicking properties of the early visual system. Both models produced classification and generalization performance in the 75%–80% range when classifying where experts tend to look. A validation study using regions identified by the AIM model as diagnostic demonstrates that human experts perform better when given regions of high diagnosticity. The computational nature of the metrics may help guard against wrongful convictions, as well as provide a quantitative measure of the strength of evidence in casework.