Dennis E. Egan

Chunking in recall of symbolic drawings.

Three experiments explored memory for symbolic circuit drawings using skilled electronics technicians and novice subjects. In the first experiment a skilled technician reconstructed circuit diagrams from memory. Recall showed marked “chunking”, or grouping, by functional units similar to Chess Masters’ recall of chess positions. In the second experiment skilled technicians were able to recall more than were novice subjects following a brief exposure of the drawings. This advantage did not hold for randomly arranged symbols. In the third experiment the size of chunks retrieved systematically increased with additional study time. Supplementary analyses suggested that the chunking by skilled subjects was not an artifact of spatial proximity and chunk statistics, and that severe constraints are placed on any explanation of the data based on guessing. It is proposed that skilled subjects identify the conceptual category for an entire drawing, and retrieve elements using a generate-and-test process.

Formative design evaluation of superbook

SuperBook is a hypertext browsing system designed to improve the usability of conventional documents. Successive versions of SuperBook were evaluated in a series of behavioral studies. Students searched for information in a statistics text. presented either in conventional printed form or in SuperBook form. The best version of SuperBook enabled students to answer search questions more quickly and accurately than they could with the conventional text. Students wrote higher quality “open-book” essays using SuperBook than they did with the conventional text, and their subjective ratings of the documentation strongly favored SuperBook. This work is a case study of formative design-evaluation. Behavioral evaluation of the first version of SuperBook showed how design factors and user strategies affected search and established baseline performance measures with printed text. The second version of SuperBook was implemented with the goal of improving search accuracy and speed. User strategies that had proved effective in the first study were made very easy and attractive to use. System response time for common operations was greatly improved. Behavioral evaluation of the new SuperBook demonstrated its superiority to printed text and suggested additional improvements that were incorporated into “MiteyBook,” a SuperBook implementation for PC-size screens. Search with MiteyBook proved to be approximately 25 percent faster and 25 percent more accurate than that obtained with a conventional printed book.

Learning to use a text editor: some learner characteristics that predict success

Why do some people have much more difficulty than others in learning a computer-based skill? To answer this question, we observed first-time users of computers as they learned to use a computer text editor. In two experiments, older people had more trouble than younger people and those who scored low on a stanbdard test of Spatial Memory had greater difficulty than high scorers. These correlations were stable over several hours of practice and did not vary as a function of the type of terminal used or specific editing problems attempted. Correlations involving Age and Spatial Memory could not be explained by other characteristics such as amount of education, reasoning ability, or associative memory ability. Results like these that relate learning difficulty to specific characteristics of people ultimately may suggest ways to change computer interface design or training to accommodate a wider range of users.

Behavioral evaluation and analysis of a hypertext browser

Students performed a variety of tasks using a statistics text presented either in conventional printed form or via the text browser “SuperBook” (Remde, Gomez and Landauer [18]). Students using SuperBook answered more search questions correctly, wrote higher quality “open-book” essays, and recalled certain incidental information better than students using the conventional text. Subjective ratings overwhelmingly favored SuperBook. The advantage of SuperBook appears to be particularly strong for questions that are not anticipated by the authors organization of a text.

Hypertext for the electronic library?: CORE sample results

The Chemistry Online Retrieval Experiment, or CORE project, is studying the possibility of creating a useful, usable electronic library for chemistry researchers. In a preliminary study, chemists were observed performing five different tasks representative of typical uses of the scientific journal literature. The tasks simulated browsing journals, answering specific questions given a citation to an article, answering specific questions given no citation, writing essays to summarize and integrate information, and finding “analogous transformations” for chemical reactions. Chemists carried out these tasks using one of three systems: (a) t.lheprinted journals supplemented with a widely used printed index system, (b) a hypertext system (the SuperBook@ document browser), or (c) a new electronic system (Pixlook) that incorporates traditional document retrieval methods plus full text indexing and delivers bitmap images of journal pages. Both electronic systems had a large advantage over the printed system for search and essay tasks. SuperBook users were faster and more accurate than Pixlook users at finding information relevant to browsing and search topics. Certain SuperBook hypertext features, however, did not work as well as Pixlook for displaying target articles. The patterns of data and log files of subjects suggest how SuperBook, Pixlook and related systems might be improved.

Testing Based on Understanding: Implications from Studies of Spatial Ability.

In this essay, the information-processing approach to studying abilities is described, and results of information-processing research on spatial ability are analyzed in some detail. Performance on spatial tasks is shown to consist of a sequence of distinct mental operations which appear to be general across subjects, and which can be individually measured. It is argued that our present understanding of spatial tasks implies new interpretations for some classical concepts in psychological testing, and suggests how research in the assessment of abilities might proceed.

Differences in mental representations spontaneously adopted for reasoning.

Retrospective reporting was used to show that people spontaneously adopt different mental representations for reasoning. In two experiments, subjects solved a large number of threeterm series reasoning problems and then gave retrospective reports (verbal protocols, drawings, and forced-choice strategy selections) about their solutions. A majority of subjects’ reports could be classified reliably into two groups. One group (abstract directional thinkers) claimed to construct a mental ordering of the three geometric figures used as the terms in the problems. A second group (concrete properties thinkers) claimed to attribute physical properties to mental geometric objects. In both experiments, abstract directional thinkers made few errors and were sensitive to the number of pivot-first premises in a problem. Concrete properties thinkers made more errors and were sensitive to the use of inverse relations and the number of alternations between a relation and its inverse as a problem was read. Quantitative models of the two kinds of reasoning are presented. Implications are discussed concerning theories of reasoning, tests of reasoning, and the usefulness of retrospective reporting as a general method.

An Analysis of Spatial Orientation Test Performance.

Abstract Spatial Orientation ability correlates with important criteria such as achievement in calculus and physics, but this ability has not been investigated systematically. Performance on individual items adapted from a standard test of Spatial Orientation was studied. Subjects judged whether aerial views would be seen by an observer oriented in various ways. For practiced subjects, the time to answer items was an approximately linear function of the number of abstract spatial dimensions on which the aerial view and the observers orientation were consistent. Practice led to lower error rates and lower intercepts for the response-time functions. Subjects ability correlated with the linearity of their response-time functions suggesting that lower ability subjects fail to code one or more spatial dimensions. A model specifying serial, self-terminating comparison of abstract spatial dimensions is proposed as an ideal which subjects approach after practice.

Learning to Use a Text Editor: Some Learner Characteristics that Predict Success

Why do some people have much more difficulty than others in learning a computer-based skill? To answer this question, we observed first-time users of computers as they learned to use a computer text editor. In two experiments, older people had more trouble than younger people and those who scored low on a stanbdard test of Spatial Memory had greater difficulty than high scorers. These correlations were stable over several hours of practice and did not vary as a function of the type of terminal used or specific editing problems attempted. Correlations involving Age and Spatial Memory could not be explained by other characteristics such as amount of education, reasoning ability, or associative memory ability. Results like these that relate learning difficulty to specific characteristics of people ultimately may suggest ways to change computer interface design or training to accommodate a wider range of users.

Learner characteristics that predict success in using a text-editor tutorial

Today, it is not unusual for secretaries to use computer-based word-processing systems to deal with manuscripts, correspondence, and memos. In the future, such functions as updating personal calendars, filing, and leaving messages undoubtedly will be handled by computers. For all these functions, people without a technical background are required to interact effectively with a computer system. A persons introduction to computers often begins with an attempt to learn how to use a text editor. Thus, knowing how to use a text editor is a requirement for a growing number of jobs. The importance of text editing is underscored by the recent psychological research devoted to understanding this skill [1,2,3,5].