Information relationships in PROLOG programs: how do programmers comprehend functionality?

doi:10.1016/S0020-7373(05)80131-2

International Journal of Man-Machine Studies

Volume 35, Issue 3, September 1991, Pages 313-328

https://doi.org/10.1016/S0020-7373(05)80131-2 Get rights and content

Within the context of software development, psychological complexity is a measure of the difficulty a programmer experiences when interacting with a program. To date there has been little research to investigate models of program comprehension as a basis for developing psychological complexity metrics. The purpose of this study is to identify information relationships that reflect the organization of programmers' cognitive models during the comprehension of unfamiliar PROLOG programs. An analysis of frequency and temporal ordering of subject protocols provides support for a two-model theory of PROLOG comprehension. During comprehension, programmers construct both a program model based on the detection of data structure relationships and a domain or real-world model based on the detection of function relationships.

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Cited by (29)

Systematic literature review of empirical studies on mental representations of programs
2020, Journal of Systems and Software
Citation Excerpt :
Another group of studies included in our review found that programmers formed mental representations at varying levels of abstraction. Studies performed by Pennington (1987b), Bergantz and Hassell (1991), Burkhardt et al. (1997), Burkhardt et al. (2002), Ramalingam and Wiedenbeck (1997), Corritore and Wiedenbeck (1999), Wiedenbeck and Ramalingam (1999), Wiedenbeck et al. (1999), Mosemann and Wiedenbeck (2001), and Parkin (2004) support the two model theory that programmers form low level program models and high level situation or domain models during the comprehension process. Studies conducted by von Mayrhauser and Vans (1994, 1995, 1996, 1998), Vans (1996), von Mayrhauser et al. (1997), and Vans et al. (1999) found that programmers formed mental models at three levels of abstraction and switched between them during the comprehension process, with the program model as the lowest level, the situation model as the intermediate level, and the domain model as the highest level of abstraction.
Programmers are frequently tasked with modifying, enhancing, and extending applications. To perform these tasks, programmers must understand existing code by forming mental representations. Empirical research is required to determine the mental representations constructed during program comprehension to inform the development of programming languages, instructional practices, and tools. To make recommendations for future work a systematic literature review was conducted that summarizes the empirical research on mental representations formed during program comprehension, how the methods and tasks have changed over time, and the research contributions.
The data items included in the systematic review are empirical studies of programmers that investigated the comprehension and internal representation of code written in a formal programming language. The eligibility criteria used in the review were meant to extract studies with a focus on knowledge representation as opposed to knowledge utilization.
The results revealed a lack of incremental research and a dramatic decline in the research meaning that newly developed or popularized languages and paradigms have not been a part of the research reviewed. Accordingly, we argue that there needs to be a resurgence of empirical research on the psychology of programming to inform the design of tools and languages, especially in new and emerging paradigms.
Pair programming and the mysterious role of the navigator
2008, International Journal of Human Computer Studies
Citation Excerpt :
For example, Brooks (1983) suggests the existence of a set of five ‘domains’ (problem, identifier, algorithmic, programming language and execution) and Pennington (1987) mixes abstraction and domain in her discussion of a detailed domain (of specific programming operations and variables), a programme domain (of routines and files) and a real-world domain. Bergantz and Hassell (1991) also discuss programming as requiring hierarchical models of abstract levels of functionality. Here we refer to the term ‘levels of abstraction’ to consider both level of granularity and domain.
Computer programming is generally understood to be highly challenging and since its inception a wide range of approaches, tools and methodologies have been developed to assist in managing its complexity. Relatively recently the potential benefits of collaborative software development have been formalised in the practice of pair programming. Here we attempt to ‘unpick’ the pair programming process through the analysis of verbalisations from a number of commercial studies. We focus particularly on the roles of the two programmers and what their key characteristics and behaviours might be. In particular, we dispute two existing claims: (i) that the programmer who is not currently typing in code (“the navigator”) is constantly reviewing what is typed and highlighting any errors (i.e. acting as a reviewer) and (ii) that the navigator focuses on a different level of abstraction as a way of ensuring coverage at all necessary levels (i.e. acting as a foreman). We provide an alternative model for these roles (“the tag team”) in which the driver and navigator play much more equal roles. We also suggest that a key factor in the success of pair programming may be the associated increase in talk at an intermediate level of abstraction.
A survey of external representations employed in object-oriented programming environments
2003, Journal of Visual Languages and Computing
This document presents an overview of the program visualisations additional to the program code provided by some of the most popular object-oriented programming environments to support tasks involving program comprehension. These representations were compared in terms of the programming aspects they highlight and of their information modality. Those with common characteristics according to these criteria were identified. Finally, a brief analysis of these common representations in terms of Green's Cognitive Dimensions is presented.
Two questions arising from this survey are (a) whether representations additional to the code should be redundant and highlight similar information to the main notation or be complementary and highlight different programming aspects and (b) which factors might increase the cognitive difficulty of co-ordinating these additional representations and the program code. More theoretical knowledge about the way these additional representations influence the comprehension of computer programs seems to be needed.
Focal structures and information types in Prolog
2001, International Journal of Human Computer Studies
Several studies have suggested that the mental structures of programmers of procedural languages have a close relationship with a model of structural knowledge related to functional information known as programming Plans. It also has been claimed that experienced programmers organize this representation in a hierarchical structure where some elements of Plans are focal or central to them. However, it is not clear that this is the case for other types of programming languages, especially for those which are significantly different from the procedural paradigm.
The study reported in this paper investigates whether these claims are true for Prolog, a language which has important differences to procedural languages. Prolog does not have obvious syntactic cues to mark blocks of code (begin/end, repeat/until, etc). Also, its powerful primitives (unification and backtracking) and the extensive use of recursion might influence how programmers comprehend Prolog code in a significant way.
The findings of the study suggest that Plans and functional information are important for Prolog programmers, but that there is also at least another model of structural knowledge valid for this language. This model of structural knowledge, Prolog schemas, is related to data structure information and it seems that a hierarchical organisation that highlights the relevance of some of its elements as focal is valid for Prolog. These results support the view that comprehension involves the detection of varying aspects of the code and that each of the structures related to these aspects might have their own organization and hierarchical relations.
Exploratory study of program comprehension strategies of procedural and object-oriented programmers
2001, International Journal of Human Computer Studies
This exploratory study examines the nature of program understanding strategies employed during a series of comprehension and maintenance activities carried out over time. Two dimensions of comprehension were examined: the direction of comprehension and the breadth of comprehension. Thirty expert procedural and object-oriented (OO) programmers studied a program and then performed modifications during two sessions held 1 week apart. The results showed that the direction of comprehension was mixed. The OO programmers tended to use a strongly top-down approach to program understanding during the early phase of familiarization with the program but used an increasingly bottom-up approach during the subsequent maintenance tasks. The procedural programmers used a more bottom-up orientation even during the early phase, and this bottom-up approach became even stronger during the maintenance tasks. The breadth of the programmers' comprehension was found to be greater for the procedural programmers than for the object-oriented programmers. However, after carrying out a series of tasks, all programmers had examined the majority of the program code. The results suggest that, regardless of paradigm, expert programmers eventually build a broad systematic, rather than a localized, view of a program over time.
Novice comprehension of small programs written in the procedural and object-oriented styles
1999, International Journal of Human Computer Studies
This research studied the comprehension of small procedural and object-oriented programs by novice programmers. The objective was to find out what kinds of information novice programmers extract from small programs and to infer from this the mental representation formed during program comprehension. In particular, the question was whether novices' mental representations focus more on domain-level or program-level knowledge and whether the mental representation of object-oriented program differ from procedural programs. The experiment indicated that novices tend to develop a mental representation of small object-oriented programs strong in function-related knowledge, but weaker in data flow and program-related knowledge. By contrast, novices' mental representations of small procedural programs were stronger in program-related knowledge. The results are discussed in terms of theories of program comprehension and programming pedagogy.

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Information relationships in PROLOG programs: how do programmers comprehend functionality?

International Journal of Man-Machine Studies

International Journal of Man-Machine Studies

Information Processing & Management

Cognitive Psychology

Problem solving and the development of abstract categories in program languages

Memory & Cognition

Skilled memory

In search of software complexity

A simple measure of software complexity

ACM Sigmetrics

Advancing the study of programming with computer-aided protocol analysis