Competitive Processes in Cross‐Situational Word Learning

Cross‐situational word learning, like any statistical learning problem, involves tracking the regularities in the environment. However, the information that learners pick up from these regularities is dependent on their learning mechanism. This article investigates the role of one type of mechanism in statistical word learning: competition. Competitive mechanisms would allow learners to find the signal in noisy input and would help to explain the speed with which learners succeed in statistical learning tasks. Because cross‐situational word learning provides information at multiple scales—both within and across trials/situations—learners could implement competition at either or both of these scales. A series of four experiments demonstrate that cross‐situational learning involves competition at both levels of scale, and that these mechanisms interact to support rapid learning. The impact of both of these mechanisms is considered from the perspective of a process‐level understanding of cross‐situational learning.     

Contextual analysis of home environment factors influencing the acquisition of early reading skills in Zambian families

This study examined the effect of home environment factors in the acquisition of early reading skills (orthographic awareness and decoding competence). To assess these factors, a sample of seventy-two (72) first grade learners (females?=?55%; age range?=?7–8 years) and their maternal parents (age range 26–61 years old) from low SES in Zambia's capital city, Lusaka were recruited. Parents, in response to a home literacy questionnaire, reported on their attitudes towards reading, literacy teaching in the home, the home literacy environment, presence of reading materials for adults and children, parental education, occupation, family size and family possessions. Two measures of reading skill were administered at school. Correlations revealed that parental education, occupation and the size of the family were not significantly associated with the reading measures. Family possessions, parental reading attitudes, literacy activities, and reading materials significantly predicted orthographic awareness. In predicting decoding competence, only family possessions, parental reading attitudes and literacy activities were predictive. Regardless of the context, children experience literacy in varied forms and quantities.     

Probabilities on Sentences in an Expressive Logic

Automated reasoning about uncertain knowledge has many applications. One difficulty when developing such systems is the lack of a completely satisfactory integration of logic and probability. We address this problem directly. Expressive languages like higher-order logic are ideally suited for representing and reasoning about structured knowledge. Uncertain knowledge can be modeled by using graded probabilities rather than binary truth values. The main technical problem studied in this paper is the following: Given a set of sentences, each having some probability of being true, what probability should be ascribed to other (query) sentences? A natural wish-list, among others, is that the probability distribution (i) is consistent with the knowledge base, (ii) allows for a consistent inference procedure and in particular (iii) reduces to deductive logic in the limit of probabilities being 0 and 1, (iv) allows (Bayesian) inductive reasoning and (v) learning in the limit and in particular (vi) allows confirmation of universally quantified hypotheses/sentences. We translate this wish-list into technical requirements for a prior probability and show that probabilities satisfying all our criteria exist. We also give explicit constructions and several general characterizations of probabilities that satisfy some or all of the criteria and various (counter)examples. We also derive necessary and sufficient conditions for extending beliefs about finitely many sentences to suitable probabilities over all sentences, and in particular least dogmatic or least biased ones. We conclude with a brief outlook on how the developed theory might be used and approximated in autonomous reasoning agents. Our theory is a step towards a globally consistent and empirically satisfactory unification of probability and logic.     

A prelearning manipulation falsifies a pure associational deficit account of retrieval shift during skill acquisition

ABSTRACT

Older adults adopt memory-based response strategies during consistent practice more slowly and less completely than younger adults. In two experiments, participants either prelearned all, half, or none of the noun-pair stimuli prior to the completion of a standard noun-pair lookup task. Higher proportions of prelearning generally led to a faster and more complete strategic shift from visual scanning to memory retrieval during the lookup task, and a strong prelearning criterion for all items eliminated the age-related slowing of retrieval shift. However, the 50% prelearned condition resulted in strategy shift that was inconsistent with simple mechanistic associative learning, revealing a strategic set that was retrieval-avoidant in older adults.     

Imageability,age of acquisition,and frequency factors in acronym comprehension

In spite of their unusual orthographic and phonological form, acronyms (e.g., BBC, HIV, NATO) can become familiar to the reader, and their meaning can be accessed well enough that they are understood. The factors in semantic access for acronym stimuli were assessed using a word association task. Two analyses examined the time taken to generate a word association response to acronym cues. Responses were recorded more quickly to cues that elicited a large proportion of semantic responses, and those that were high in associative strength. Participants were shown to be faster to respond to cues which were imageable or early acquired. Frequency was not a significant predictor of word association responses. Implications for theories of lexical organisation are discussed.     

Perceived product instrumentality: the process of scale purification and validation

Perceived product instrumentality (PPI) is a new construct that is proposed as a key process component of a general model of family purchasing behaviour. PPI reflects the degree to which consumers, apprehended as actors of social roles, deem a product to be helpful, facilitative of role performance, compatible with role identity and congruent with the self‐concept. The objective of this paper is threefold: (1) assess the PPI unidimensionality and reliability; (2) purify the PPI scale, and (3) assess its validity. First, a pilot survey was administered to a convenience sample of men and women, who filled in four identical lists of 33 items tapping their attitudes towards durables, and exploratory factor analysis was conducted on each set to explore the overall pattern of the items relationships. Five try‐out pools of different sizes (33, 28, 15, 13 and 9 items) were involved in the analysis. The 15‐item scale was retained. Secondly, a large‐scale survey was administered to 500 couples as part of an extensive research involving comprehensive model testing. Exploratory factor analysis was conducted on the whole sample for reliability and unidimensionality assessment. At times, the analysis is done on men's and women's sub‐samples separately in order to account for eventual differences among both populations. Thirdly, confirmatory factor was conducted, splitting the sample into two random halves: the generation sample and the validation sample. The first half served for the PPI scales purification. In this case, PPI was posited as the latent variable and the scale items were posited as the manifest ones. The second served to validate the PPI theory in a system's framework: PPI was posited as a latent dependent variable while other role orientations variables were posited as latent independent variables. Copyright © 2002 Henry Stewart Publications.     

Probability, logic and the cognitive foundations of rational belief

Since Pascal introduced the idea of mathematical probability in the 17th century discussions of uncertainty and “rational” belief have been dogged by philosophical and technical disputes. Furthermore, the last quarter century has seen an explosion of new questions and ideas, stimulated by developments in the computer and cognitive sciences. Competing ideas about probability are often driven by different intuitions about the nature of belief that arise from the needs of different domains (e.g., economics, management theory, engineering, medicine, the life sciences etc). Taking medicine as our focus we develop three lines of argument (historical, practical and cognitive) that suggest that traditional views of probability cannot accommodate all the competing demands and diverse constraints that arise in complex real-world domains. A model of uncertain reasoning based on a form of logical argumentation appears to unify many diverse ideas. The model has precursors in informal discussions of argumentation due to Toulmin, and the notion of logical probability advocated by Keynes, but recent developments in artificial intelligence and cognitive science suggest ways of resolving epistemological and technical issues that they could not address.     

中学生知识获得过程是从情景记忆向语义记忆转化的过程

本研究探讨中学生的知识掌握过程。针对2001—2002年度上学期教学内容,对初中二年级学生的四门课程分别进行两次测验。对于每道选择题,学生首先选择正确答案,然后指出记忆的意识状态：记住的、知道的、猜测的。结果发现,学生记忆意识类型的转变(由记住向知道)取决于课程类型、保持时间和学生等级。对于不同课程,学生占优势的意识类型不同,自然学科知道的反应占优势,社会学科记住的反应占优势;优等生知道的反应多于其他学生;随着学习时间的延长,中学生的意识类型发生了由记住向知道的转变,这表明知识掌握过程中,中学生的知识表征发生了由情景记忆向语义记忆的转变。     

The link between knowledge and remembering in Alzheimer’s disease

Current research on the influence of cognitive support (e.g., activation of task-relevant prior knowledge, item organizability, retrieval cues) on episodic remembering in normal aging and Alzheimer’s disease (AD) is reviewed. Examining the effects of cognitive support on memory may shed light on the relationship between knowledge and remembering, and also provides relevant information pertaining to the development of cognitive intervention procedures. A series of studies from our own and other laboratories reveal a number of interesting empirical regularities. First, AD results in problems in utilizing cognitive support for improving memory. Conceivably, this reduction in cognitive reserve capacity is due to both the overall severity of the episodic memory impairment in AD, as well as to dementia-related deficits in the semantic network that guides encoding and retrieval of information. Nevertheless, AD patients are able to utilize cognitive support in episodic memory tasks, although they typically need more support than their healthy aged counterparts to show memory facilitation. Specifically, it is critical to provide support at both encoding and retrieval in order to demonstrate performance gains in AD. Moreover, successful utilization of retrieval support in this disease is most likely to occur when the encoding requirements force the individual to engage in elaborative cognitive activity (e.g., generation of task-relevant knowledge, categorical organization). Finally, a reduction in cognitive reserve capacity occurs later in the pathogenesis of AD than a generalized episodic memory impairment. This observation reflects the insidious nature of AD, and suggests that the transition from normal aging to AD may be continuous rather than discrete.     

Instructor and student knowledge of study strategies

Students' self-reported study skills and beliefs are often inconsistent with empirically supported (ES) study strategies. However, little is known regarding instructors' beliefs about study skills and if such beliefs differ from those of students. In the current study, we surveyed college students' and instructors' knowledge of study strategies and had both groups evaluate the efficacy of learning strategies described in six learning scenarios. Results from the survey indicated that students frequently reported engaging in methods of studying that were not optimal for learning. Instructors' responses to the survey indicated that they endorsed a number of effective study skills but also held several beliefs inconsistent with research in learning and memory (e.g., learning styles). Further, results from the learning scenarios measure indicated that instructors were moderately more likely than students to endorse ES learning strategies. Collectively, these data suggest that instructors exhibited better knowledge of effective study skills than students, although the difference was small. We discuss several notable findings and argue for the improvement of both students' and instructors' study skill knowledge.