Comprehension and recall of miniature programs

Abstract

Differences in the comprehensibility of programming notations can arise because their syntax can make them cognitively unwieldy in a generalized way ( Mayer, 1976), because all notations are translated into the same “mental language“ but some are easier to translate than others (Shneiderman & Mayer, 1979), or because the mental operations demanded by certain tasks are harder in some notations than in others ( Green, 1977). The first two hypotheses predict that the relative comprehensibility of two notations will be consistent across all tasks, whereas the mental operations hypothesis suggests that particular notations may be best suited to particular tasks. The present experiment used four notations and 40 non-programmers to test these hypotheses. Two of the notations were procedural and two were declarative, and one of each pair contained cues to declarative or procedural information, respectively. Different types of comprehension question were used (“sequential“ and “circumstantial“); a mental operations analysis predicted that procedural languages would be “matched” with sequential questions, and declarative languages with circumstantial questions. Questions were answered first from the printed text, and then from recall. Subjects performed best on “matched pairs” of tasks and languages. Perceptually-based cues improved the performance on “unmatched pairs” better than non-perceptual cues when answering from the text, and both types of cues improved performance on “unmatched pairs” in the recall stage. These results support the mental operations explanation. They also show that the mental representation of a program preserves some features of the original notation; a comprehended program is not stored in a uniform “mental language”.