Time to completion of web-based physics problems with tutoring

We studied students performing a complex learning task, that of solving multipart physics problems with interactive tutoring on the web. We extracted the rate of completion and fraction completed as a function of time on task by retrospectively analyzing the log of student-tutor interactions. There was a spontaneous division of students into three groups, the central (and largest) group (about 65% of the students) being those who solved the problem in real time after multiple interactions with the tutorial program (primarily receiving feedback to submitted wrong answers and requesting hints). This group displayed a sigmoidal fraction-completed curve as a function of logarithmic time. The sigmoidal shape is qualitatively flatter for problems that do not include hints and wrong-answer responses. We argue that the group of students who respond quickly (about 10% of the students) is obtaining the answer from some outside source. The third group (about 25% of the students) represents those who interrupt their solution, presumably to work offline or to obtain outside help.     

The physics of evolution: From chaos to evolution and deep ecology

This paper summarizes the various physical science elements of the evolutionary story. The “nonlinear” revolution includes chaos, self‐organization theory, the thermodynamics of evolution, and biological evolution. The key result of the revolution is a physical understanding of how order emerges and change is driven. This paper brings the lessons of each branch of the revolution together into a single easily understood thread. The unexpected result of this revolution is an understanding of evolution as a single inexorable physical process that has given rise to everything from molecules to humankind. Here evolution is driven by energy flow and involves increasing efficiency, the growth of complexity, and the acceleration of change. This paper ties the resulting physical insights to an evolving ecological world view, looks at its ties to spirituality and applies the rules that govern the growth of complexity to business and its current crisis. The net result of the nonlinear revolution is a radical change in our everyday understanding of how the world works, a shift away from classical science's machine world to the vision of an evolving deeply ecologically intertwined world.     

Some teasers concerning conditional probabilities

A family of notorious teasers in probability is discussed. All ask for the probability that the objects of a certain pair both have some property when information exists that at least one of them does. These problems should be solved using conditional probabilities, but cause difficulties in characterizing the conditioning event appropriately. In particular, they highlight the importance of determining the way information is being obtained. A probability space for modeling verbal problems should allow for the representation of the given outcome and the statistical experiment which yielded it. The paper gives some psychological reasons for the tricky nature of these problems, and some practical tips for handling them.     

Mother and father language input to young children: Contributions to later language development

There has been little research comparing the nature and contributions of language input of mothers and fathers to their young children. This study examined differences in mother and father talk to their 24 month-old children. This study also considered contributions of parent education, child care quality and mother and father language (output, vocabulary, complexity, questions, and pragmatics) to children's expressive language development at 36 months. It was found that fathers' language input was less than mothers' language input on the following: verbal output, turn length, different word roots, and wh-questions. Mothers and fathers did not differ on type-token ratio, mean length of utterance, or the proportion of questions. At age 36 months, parent level of education, the total quality of child care and paternal different words were significant predictors of child language. Mothers' language was not a significant predictor of child language.     

Semantic differential studies of children's language development: Some methodological problems

A semantic differential study of development of antonym meanings revealed methodological problems (e.g., concept-scale interaction and developmental changes in scale-checking style) not fully considered in previous semantic differential investigations of child language development. Twenty adjectives were rated on 10 scales by subjects from grades K to 5 (approximately 6 through 11 years old) and adults. Analyses by means, polarity ratings, and average sums of squared differences failed to yield consistent developmental trends. Subjects' choices of scale ratings did show clear age-related differences: Grades K and 1 chose extreme ratings almost exclusively; grades 2 through 4 showed an increase in neutral choices and decreases in extreme ratings; grades 4 and 5 and adults chose extreme ratings least often, neutral choices most often, and more intermediate ratings than any younger subjects. Results show that scale choice is a crucial factor in designing semantic differential studies with children, there is a low correlation between mean scores and ratings given by individual children, and shifts in scale-checking style should be considered when interpreting apparent developmental changes in children's semantic differential ratings.     

Some observations on a Popperian experiment concerning observation

In several places Popper describes a little experiment in which an audience is given the non-specific command Observe! He draws a number of conclusions from this experiment, in particular that observation takes place in the presence of theoretical problems, questions, hypotheses or points of view. The paper argues that while Popper's experiment is instructive, it hardly supports the strong conclusions he draws about the theory-dominance of observation in science. In particular, it is argued that talk of principles of selection which guide us to relevant observations, rather than the host of irrelevant observations of the naive inductivist, is misleading. Rather, it is the goals, aims, motives or interests of an observer that guide observation and these need not always involve a theoretical component.     

Tacit and accessible understanding of language

The empirical nature of our understanding of language is explored. I first show that there are several important and different distinctions between tacit and accessible awareness. I then present empirical evidence concerning our understanding of language. The data suggests that our awareness of sentence-meanings is sometimes merely tacit according to one of these distinctions, but is accessible according to another. I present and defend an interpretation of this mixed view. The present project is shown to impact on several diverse areas, including inferential role semantics and holism, the nature of learning, and the role of linguistics in the law. I am indebted to a number of people for their useful feedback, especially Peter Ludlow, Paul Pietroski, and two anonymous reviewers. Earlier versions of this paper were presented at an Eastern meeting of the APA, a meeting of the Society for Exact Philosophy at Simon Fraser University, and at a semantics workshop in Ottawa, Canada. I greatly appreciate the comments from those audiences.     

Categorization and representation of physics problems by experts and novices

The representation of physics problems in relation to the organization of physics knowledge is investigated in experts and novices. Four experiments examine (a) the existence of problem categories as a basis for representation; (b) differences in the categories used by experts and novices; (c) differences in the knowledge associated with the categories; and (d) features in the problems that contribute to problem categorization and representation. Results from sorting tasks and protocols reveal that experts and novices begin their problem representations with specifiably different problem categories, and completion of the representations depends on the knowledge associated with the categories. For, the experts initially abstract physics principles to approach and solve a problem representation, whereas novices base their representation and approaches on the problem's literal features.     

Interactions of language and memory in deaf children and adults

This article reviews theoretical and empirical issues concerning the relations of language and memory in deaf children and adults. An integration of previous studies, together with the presentation of new findings, suggests that there is an intimate relation between spoken language and memory. Either spoken language or sign language can serve as a natural mode of communication for young children (deaf or hearing), leading to normal language, social, and cognitive development. Nevertheless, variation in spoken language abilities can be shown to have a direct impact on memory span. Although the ways in which memory span can effect other cognitive processes and academic achievement are not considered in depth here, several variables that can have direct impact on the language-memory interaction are considered. These findings have clear implications for the education of deaf children.     

Language transfer and blocking in second language vocabulary learning

The influence of different vocabulary instructional techniques upon the acquisition of different language words was examined in two experiments. In Experiment 1, comparisons were made between the learning of Chinese and French words employing both paired-associate presentations and spacing procedures. The results supported the view that language transfer affects the acquisition of second language words, with more French words being learned than Chinese words. The superiority of the spacing procedure over the paired-associate presentation found in these results suggested that the spacing method diminished the adverse effects of blocking and thus enhanced learning. However, no significant interaction between the teaching procedures and different language words was detected. That is, under the spacing procedure, greater improvement in learning of Chinese words was not found. The experiment was thus modified by substituting the spacing procedure with aural feedback in Experiment 2. In this experiment, a significant interaction between these two factors was detected. That is, the recall for French was more than Chinese in the paired-associate condition, however, under the aural feedback, performance in Chinese was statistically equivalent to that in French. Hence, these findings may contradict the prediction of language transfer. It appears that the phenomenon of language transfer may be far less important in vocabulary learning than the use of a method of instruction which neutralises the negative effects of blocking.     

Words and possible words in early language acquisition

In order to acquire language, infants must extract its building blocks—words—and master the rules governing their legal combinations from speech. These two problems are not independent, however: words also have internal structure. Thus, infants must extract two kinds of information from the same speech input. They must find the actual words of their language. Furthermore, they must identify its possible words, that is, the sequences of sounds that, being morphologically well formed, could be words. Here, we show that infants’ sensitivity to possible words appears to be more primitive and fundamental than their ability to find actual words. We expose 12- and 18-month-old infants to an artificial language containing a conflict between statistically coherent and structurally coherent items. We show that 18-month-olds can extract possible words when the familiarization stream contains marks of segmentation, but cannot do so when the stream is continuous. Yet, they can find actual words from a continuous stream by computing statistical relationships among syllables. By contrast, 12-month-olds can find possible words when familiarized with a segmented stream, but seem unable to extract statistically coherent items from a continuous stream that contains minimal conflicts between statistical and structural information. These results suggest that sensitivity to word structure is in place earlier than the ability to analyze distributional information. The ability to compute nontrivial statistical relationships becomes fully effective relatively late in development, when infants have already acquired a considerable amount of linguistic knowledge. Thus, mechanisms for structure extraction that do not rely on extensive sampling of the input are likely to have a much larger role in language acquisition than general-purpose statistical abilities.     

Frames of reference in spatial language acquisition

Languages differ in how they encode spatial frames of reference. It is unknown how children acquire the particular frame-of-reference terms in their language (e.g., left/right, north/south). The present paper uses a word-learning paradigm to investigate 4-year-old English-speaking children’s acquisition of such terms. In Part I, with five experiments, we contrasted children’s acquisition of novel word pairs meaning left-right and north-south to examine their initial hypotheses and the relative ease of learning the meanings of these terms. Children interpreted ambiguous spatial terms as having environment-based meanings akin to north and south, and they readily learned and generalized north-south meanings. These studies provide the first direct evidence that children invoke geocentric representations in spatial language acquisition. However, the studies leave unanswered how children ultimately acquire “left” and “right.” In Part II, with three more experiments, we investigated why children struggle to master body-based frame-of-reference words. Children successfully learned “left” and “right” when the novel words were systematically introduced on their own bodies and extended these words to novel (intrinsic and relative) uses; however, they had difficulty learning to talk about the left and right sides of a doll. This difficulty was paralleled in identifying the left and right sides of the doll in a non-linguistic memory task. In contrast, children had no difficulties learning to label the front and back sides of a doll. These studies begin to paint a detailed account of the acquisition of spatial terms in English, and provide insights into the origins of diverse spatial reference frames in the world’s languages.     

外语焦虑、紧张情绪与认知负荷对外语说谎的影响：来自中-英双语者的证据

采用错误陈述范式探究中-英双语者用母语和外语说真话和说谎时的认知神经差异,涉及外语焦虑、认知负荷和说谎诱发的紧张情绪。对P200和CNV观察发现:(1)中-英双语者用英语说真话的P200波幅比用母语大,说明被试用英语说话时受外语焦虑情绪影响;(2)中-英双语者用英语说谎与说真话的P200波幅无显著差异,但用母语说谎和讲真话的P200波幅差异显著,说明被试用外语说谎没有用母语说谎诱发的紧张情绪大;(3)中-英双语者说谎时的CNV波幅比说真话时大,说明被试说谎比说真话的认知负荷更大;(4)中-英双语者用英语说谎时的CNV波幅比用汉语说谎时大,说明被试用外语说谎比用母语说谎产生了更大的认知负荷。相关分析表明,英语熟练程度是影响中-英双语者用母语和外语说谎时的认知神经差异的重要变量。     

语言转换对非熟练双语者不同认知控制成分的即时影响

语言转换情境是否影响非熟练双语者的认知控制存在争议。实验1和实验2分别采用不同的实验范式探讨语言转换对非熟练双语者的认知控制是否会有即时的影响, 以及对不同认知控制成分的影响是否会有不同。结果表明, 语言转换情境能够即时地促进反应抑制, 阻碍干扰抑制, 但对认知灵活性没有影响, 同时说明了反应抑制、干扰抑制和认知灵活性属于3种不同的认知成分, 其内在作用机制不同。此外, 研究结果还进一步说明了双语者的认知控制优势是双语者长期双语使用的结果, 为双语优势的内在机制提供了实验支持。     

Some neglected problems in IRT

The paper addresses three neglected questions from IRT. In section 1, the properties of the “measurement” of ability or trait parameters and item difficulty parameters in the Rasch model are discussed. It is shown that the solution to this problem is rather complex and depends both on general assumptions about properties of the item response functions and on assumptions about the available item universe. Section 2 deals with the measurement of individual change or “modifiability” based on a Rasch test. A conditional likelihood approach is presented that yields (a) an ML estimator of modifiability for given item parameters, (b) allows one to test hypotheses about change by means of a Clopper-Pearson confidence interval for the modifiability parameter, or (c) to estimate modifiability jointly with the item parameters. Uniqueness results for all three methods are also presented. In section 3, the Mantel-Haenszel method for detecting DIF is discussed under a novel perspective: What is the most general framework within which the Mantel-Haenszel method correctly detects DIF of a studied item? The answer is that this is a 2PL model where, however, all discrimination parameters are known and the studied item has the same discrimination in both populations. Since these requirements would hardly be satisfied in practical applications, the case of constant discrimination parameters, that is, the Rasch model, is the only realistic framework. A simple Pearsonx ² test for DIF of one studied item is proposed as an alternative to the Mantel-Haenszel test; moreover, this test is generalized to the case of two items simultaneously studied for DIF.     

Parents’ early book reading to children: Relation to children's later language and literacy outcomes controlling for other parent language input

It is widely believed that reading to preschool children promotes their language and literacy skills. Yet, whether early parent–child book reading is an index of generally rich linguistic input or a unique predictor of later outcomes remains unclear. To address this question, we asked whether naturally occurring parent–child book reading interactions between 1 and 2.5 years‐of‐age predict elementary school language and literacy outcomes, controlling for the quantity of other talk parents provide their children, family socioeconomic status, and children's own early language skill. We find that the quantity of parent–child book reading interactions predicts children's later receptive vocabulary, reading comprehension, and internal motivation to read (but not decoding, external motivation to read, or math skill), controlling for these other factors. Importantly, we also find that parent language that occurs during book reading interactions is more sophisticated than parent language outside book reading interactions in terms of vocabulary diversity and syntactic complexity.