The theoretical framework presented in this article explains expert performance as the end result of individuals ' prolonged efforts to improve performance while negotiating motivational and external constraints. In most domains of expertise, individuals begin in their childhood a regimen of effortful activities (deliberate practice) designed to optimize improvement. Individual differences, even among elite performers, are closely related to assessed amounts of deliberate practice. Many characteristics once believed to reflect innate talent are actually the result of intense practice extended for a minimum of 10 years. Analysis of expert performance provides unique evidence on the potential and limits of extreme environmental adaptation and learning. Our civilization has always recognized exceptional individuals, whose performance in sports, the arts, and science is vastly superior to that of the rest of the population. Speculations on the causes of these individuals ' extraordinary abilities and performance are as old as the first records of their achievements. Early accounts commonly attribute these individuals' outstanding performance to divine intervention, such as the

This article investigates how and why people remember the existence of hidden information. To obtain data on this kind of memory phenomenon, we observed an experienced programmer doing her own work at her own computer. The programmer's interaction with the computer generates much more information than fits on the screen at once. Most of this information is hidden, scrolled out of the way by the programming environment to make Direct all correspondence to: Erik M. Altmann, George Mason University, Human Factors & Applied Cognition, Mailstop 2E5, Fairfax, VA 22030 USA; E-Mail: altmann@gmu.edu

It is known that novices show poor problem-solving performances and that they engage in a relatively inefficient inferential reasoning mode. Experts show high performances in routine situations in which they only activate knowledge. The main purpose of this work was to test the hypothesis that, under some conditions, novices may develop a more efficient diagnostic reasoning than experts, i.e. they may discover the cause of a faulty system conducting fewer tests while avoiding fixation errors. This hypothesis mainly relies on the possibility that experts may be victims of their own knowledge format (French and Sternberg, manuscript). It is tested in a faulty electronic circuit troubleshooting task. Data suggest that novices perform better than experts. Results are discussed with reference to the concepts of schema and expert error.

interaction, artificial intelligence. People make use of hidden external information, first recalling that it exists and then finding it. This dissertation investigates the memory phenomena involved in recalling that external information exists. We present data in which a programmer navigates to hidden features in a real-world task environment. We then present a model that accounts for this navigation by encoding and using simple episodic memories for having seen a feature. The model inherits constraints from its underlying cognitive architecture, which specify that learning is passive and pervasive, and that it creates simple memories that depend on the feature itself being present as a cue. The nature of these memories requires the model to recall features to its mind’s eye as cues in order to retrieve them. This retrieval process requires domain knowledge: familiarity with features in order to imagine them, and an idea of when it would be useful to recall having seen them. Recalling that a hidden feature exists prompts the model to scroll to that feature. Thus the model’s access to external information is a function of passively-encoded episodic memories, and retrieval of these memories using knowledge. As a claim applied to people, this appears to overlap with a recently-

This paper describes findings from a study conducted to analyze the behavior, knowledge, and thinking that support the highest levels of human land mine detection skill. A recent assessment of land mine detection capability concluded that “human operators perform better with any detector system than the corresponding fully automated system. ” 1 This assessment, plus evidence linking individual differences in detection ability to experience, suggests that methods, data, and theory developed in studying human expertise can be applied to the problems of land mine detection and discrimination. Studies of experts across a variety of skill domains have demonstrated that analyses of experts ’ skills can yield findings useful for designing efficient and effective training programs and supporting technology development. This initial field study was performed to (a) identify the upper levels of human mine detection capability using currently-fielded hand-held equipment and (b) model the knowledge, thinking, and techniques employed by proficient human operators. Two experienced operators showed sufficiently impressive detection performance to qualify as experts. Data also show that a skilled PSS-12 operator can detect low-metal mines with considerable accuracy. A first-approximation information-processing model of expert operator skill is presented that is based on observation of the operators ’ activities as they searched for mine targets.

We compare the effects of interrupting text dealing with familiar or unfamiliar domains with either arithmetic or sentence reading tasks. Readers were interrupted after each of the eight sentences, at the end of each sentence, or in the middle of each sentence. Previous findings of minimal effects of interruptive tasks on comprehension measures (e.g., Glanzer & Nolan, 1986) were replicated in this study. Also, as found by G!anzer and his colleagues, interruptions after each sentence of a familiar text by an unrelated sentence increased reading times by approximately 400 ms per sentence. In contrast, for difficult, unfamiliar texts, mid-sentence interruptions significantly lengthened reading times by 1262 ms for sentence and 1784 ms for arithmetic interruptions. These findings are explained in terms of Ericsson and Kintsch's (1993) memory model which proposes that skilled memory performance relies on the use of long-term memory as an extension of working memory, or long-term working memory. 3 Reading is by its very nature sequential. The glue of memory is needed, therefore, to hold the various elements of the sequence together. The eye moves from word to word, and in general each word is integrated with the previous ones as rapidly as possible (e.g., Just & Carpenter, 1987). According to Kintsch and van Dijk's (1978) model of text comprehension, sentences or phrases also form processing units, which are linked together via a short-term memory buffer. Evidence for the operation of such a buffer has been obtained in various experiments (e.g., Fletcher, 1981; Glanzer & Razel, 1974). However, reading comprehension is still possible when the use of this buffer is prevented. For instance, Glanzer and his colleagues (e.g., Fischer & Glanzer, 1986; Glanzer, Dorfman, & Kaplan, ...

Workplace learning has developed as a field both of practice and of research over the past decade. The increase in interest is due in part to heightened awareness that workplace knowledge and skills contribute to enterprise and national competitiveness, but it is also due to an increased focus on the connections to be made between theory and practice as part of an education or training experience. At the same time, new learning technologies have enhanced delivery of instruction and learning materials in workplaces. This article reviews some of the conceptualizations of workplace learning and its cognitive bases. It also examines workplaces as learning environments and considers the special challenges involved in the flexible delivery of training to workplaces.

We examined the effect of interruption on reading to determine if discourse processing is susceptible to similarity-based interference. Participants read pairs of passages, either one before the other (in the continuous condition) or with the sentences of the two passages interleaved (in the interruption condition). In addition, the similarity of the types of passages (narrative or expository) in a pair was manipulated. Performance was measured with self-paced reading time of the sentences and with accuracy in answering comprehension questions. In two experiments, interruption slowed the reading of text sentences; this effect of interruption was greatest when the interrupting text was of the same style as the primary text (an interruption-similarity effect). We discuss these results with respect to current models of the role of working memory in discourse processing. Current memory models offer differing characterisations of the information that is maintained and manipulated in working memory during cognitive tasks, and of the structure of working memory itself. Our interest in this paper is in the nature of working memory underlying language comprehension, particularly as it handles interruption during reading. Different views of working memory in language processing lead to different predictions about how interruption should affect the process of reading comprehension. A great deal of research on text memory has demonstrated that some elements of a text (such as the semantic relationships among entities, or situational aspects) are remembered better (with more accuracy and over greater periods of time) than other elements (such as the exact wording of a particular sentence; Bransford & Franks, 1971; Sachs, 1967). This suggests that different types of information from a text are represented and organised differently in memory. Several researchers have described the processes by which text representations are created and maintained

In this paper a number of principles for content-oriented cognitive psychology will be presented in the context of research into chess players' information processing. It will be argued that modern theoretical concepts of attention, imagery and memory are based on underlying concepts of capacity and format and that these concepts are not sufficiently powerful to express all phenomena associated with mental contents. Instead, one must develop a genuinely content-oriented theoretical language to discuss, for example, contents and their integration into thinking. The main problem is how to explain the contents of representations. Why do representations have precisely the contents that they have. Here the main attention will be focussed on the question how can one explain the selection of content elements in representations. To formulate the basic concepts of contentoriented thought research several issues must be discussed. Firstly, it will be shown that traditional attention and memory research is capacity-oriented and therefore unable to express mental contents. Secondly, it will be argued that there are content phenomena which must be explained by properties of other content phenomena. Thirdly, it will be shown that in chess, people integrate information into representations by using functional rules or reasons, i.e. concepts and rules, which tell why some information contents must be included in a representation. It will then be shown that people integrate information around learned `thought models' whose contents, together with functional rules or reasons, explain and clarify the contentstructure of a mental representation. It will also be argued that the analysis of contents is metascientifically closer to linguistics with its basic method of explication and content ana...

The process of knowledge elaboration is considered from the perspective of cognitive load theory. This theory assumes that the available knowledge structures in long-term memory (LTM) are used to organize and guide cognitive processing in complex learning. Accordingly, the role of external instructional guidance in the process of knowledge elaboration could be described as providing a substitute for knowledge structures missing from LTM. Thus, the executive guidance in complex learning environments is shared between the person (based on his/her LTM knowledge structures) and another expert or instructional means. This article analyzes instructional implications of this assumption. Adaptive learning environments are suggested for tailoring knowledge elaboration processes to changing characteristics of individual learners. Means for identifying and predicting the learner’s LTM-based executive guidance are proposed so that they can be utilized in the building of adaptive learning environments.