Instructional strategies and tactics for the design of introductory computer programming courses in high school

This article offers an examination of instructional strategies and tactics for the design of introductory computer programming courses in high school. We distinguish the Expert, Spiral and Reading approach as groups of instructional strategies that mainly differ in their general design plan to control students' processing load. In order, they emphasize topdown program design, incremental learning, and program modification and amplification. In contrast, tactics are specific design plans that prescribe methods to reach desired learning outcomes under given circumstances. Based on ACT* (Anderson, 1983) and relevant research, we distinguish between declarative and procedural instruction and present six tactics which can be used both to design courses and to evaluate strategies. Three tactics for declarative instruction involve concrete computer models, programming plans and design diagrams; three tactics for procedural instruction involve worked-out examples, practice of basic cognitive skills and task variation. In our evaluation of groups of instructional strategies, the Reading approach has been found to be superior to the Expert and Spiral approaches

A preliminary investigation of the use of the cloze procedure as a measure of program understanding

Program understanding is an integral part of the testing and maintenance phases of the software life cycle. There have been numerous investigations of the influence of various aspects of a program and the program- ming process on program comprehension. However, the many different measures of understanding used in these studies make any comparison or analysis difficult. Some of the different measures include time to find a bug, a comprehension quiz, ability to reproduce a functionally equivalent program without notes, time to perform a modification, Halstead's E and McCabe's complexity measure. All of these have limitations such as inability to measure both low- and high-level understanding, difficulty of administering and objectively grading, or impractical for large or non-trivial programs. Of the measures, the comprehension quiz is probably the most commonly used and accepted measure of program understanding. This paper reports on a controlled experiment that compared the "cloze" procedure and comprehension quiz as measuring program understanding. In a cloze procedure, the subjects are presented a program listing with some of the program tokens (operands, operators, reserved words, single parenthesis or brackets, etc.) replaced with blanks and are required to fill in the blanks. Our experiment tested students in sophomore, junior and senior level computer science courses. Ihese were assumed to correspond to three levels of programming experience. Each subject was given one of two versions of a sorting program and either a cloze version of the program or a comprehension quiz over it. Results for the cloze procedure closely approximated those of the comprehension quizzes for both programs and each level of experience. These results and the ease of administration and grading make the cloze procedure a potentially attractive means for measuring program understanding

Analogical Retrieval via Intermediate Features: The Goldilocks Hypothesis

Analogical reasoning has been implicated in many important cognitive processes, such as learning, categorization, planning, and understanding natural language. Therefore, to obtain a full understanding of these processes, we must come to a better understanding of how people reason by analogy. Analogical reasoning is thought to occur in at least three stages: retrieval of a source description from memory upon presentation of a target description, mapping of the source description to the target description, and transfer of relationships from source description to target description. Here we examine the first stage, the retrieval of relevant sources from long-term memory for their use in analogical reasoning. Specifically we ask: what can people retrieve from long-term memory, and how do they do it?Psychological experiments show that subjects display two sorts of retrieval patterns when reasoning by analogy: a novice pattern and an expert pattern. Novice-like subjects are more likely to recall superficiallysimilar descriptions that are not helpful for reasoning by analogy. Conversely, expert-like subjects are more likely to recall structurally-related descriptions that are useful for further analogical reasoning. Previous computational models of the retrieval stage have only attempted to model novice-like retrieval. We introduce a computational model that can demonstrate both novice-like and expert-like retrieval with the same mechanism. The parameter of the model that is varied to produce these two types of retrieval is the average size of the features used to identify matches in memory. We find that, in agreement with an intuition from the work of Ullman and co-workers regarding the use of features in visual classification (Ullman, Vidal-Naquet,& Sali, 2002), that features of an intermediate size are most useful for analogical retrieval.We conducted two computational experiments on our own dataset of fourteen formally described stories, which showed that our model gives the strongest analogical retrieval, and is most expert-like, when it uses features that are on average of intermediate size. We conducted a third computational experiment on the Karla the Hawk dataset which showed a modest effect consistent with our predictions. Because our model and Ullmans work both rely on intermediate-sized features to perform recognition-like tasks, we take both as supporting what we call the Goldilocks hypothesis: that on the average those features that are maximally useful for recognition are neither too small nor too large, neither too simple nor too complex, but rather are in the middle, of intermediate size and complexity

Effectiveness of training on algorithms versus notation for indirect addressing comprehension

This study compared two units of instruction for overcoming difficulties of beginning programmers in understanding and implementing strategies of indirect addressing. One of the units emphasized the algorithms in which indirection was used, whereas the other unit emphasized indirect notation. Both instructional units were delivered by computer to two introduction to Pascal programming classes. Students in each class were randomly divided so that each student used one or the other of the two units;These units were used prior to and were supplementary to three lectures covering indirect notation. The effectiveness of the units were determined by two posttests. One posttest, requiring students to select subscripts at several levels of indirection, was administered by computer. This test was very similar to the activities in the notation unit. The second posttest was a paper pencil activity requiring the students to complete or modify sorting algorithms in which indirection was used;Because of the explorative nature of this study and the small sample size, the findings must be viewed as tentative. However, it would appear the notation of indirection by itself is not an important source of student problems in this area. In fact, there was little evidence to suggest that either unit made a sizeable difference in the student\u27s ability to deal with indirection within the context of programming. There was an indication extra study of algorithms encouraged students to attempt to solve more problems, but this finding may be a result of the experimental conditions and may not be generalizable

The evaluation of dynamic human-computer interaction

This thesis describes the development and evaluation of a theoretical framework to account for the dynamic aspects of behaviour at the Human-Computer Interface (HCIF). The purpose behind this work is to allow for the consideration of dynamic Human-Computer Interaction (HCI) in the design of interactive computer systems, and to facilitate the generation of design tools for this purpose. The work describes an example of a design tool which demonstrates how designers of interactive computer systems may account for some aspects of the dynamics of behaviour, involved with the use of computers, in the design of new interactive systems. The thesis offers empirical and literary evidence to support the validity of the dynamic factors governing the interaction of humans with computers

Knowledge restructing and the development of expertise in computer programming

This thesis reports a number of empirical studies exploring the development of expertise in computer programming. Experiments 1 and 2 are concerned with the way in which the possession of design experience can influence the perception and use of cues to various program structures. Experiment 3 examines how violations to standard conventions for constructing programs can affect the comprehension of expert, intermediate and novice subjects. Experiment 4 looks at the differences in strategy that are exhibited by subjects of varying skill level when constructing programs in different languages. Experiment 5 takes these ideas further to examine the temporal distribution of different forms of strategy during a program generation task. Experiment 6 provides evidence for salient cognitive structures derived from reaction time and error data in the context of a recognition task. Experiments 7 and 8 are concerned with the role of working memory in program generation and suggest that one aspect of expertise in the programming domain involves the acquisition of strategies for utilising display-based information. The final chapter attempts to bring these experimental findings together in terms of a model of knowledge organisation that stresses the importance of knowledge restructuring processes in the development of expertise. This is contrasted with existing models which have tended to place emphasis upon schemata acquisition and generalisation as the fundamental modes of learning associated with skill development. The work reported here suggests that a fine-grained restructuring of individual schemata takes places during the later stages of skill development. It is argued that those mechanisms currently thought to be associated with the development of expertise may not fully account for the strategic changes and the types of error typically found in the transition between novice, intermediate and expert problem solvers. This work has a number of implications for existing theories of skill acquisition. In particular, it questions the ability of such theories to account for subtle changes in the various manifestations of skilled performance that are associated with increasing expertise. Secondly, the work reported in this thesis attempts to show how specific forms of training might give rise to the knowledge restructuring process that is proposed. Finally, the thesis stresses the important role of display-based problem solving in complex tasks such as programming and highlights the role of programming language notation as a mediating factor in the development and acquisition of problem solving strategies