The difficulty of computer programming and other design tasks is a function of the multiple abstractions that combine to form a program's meaning. Thus, comprehension of the final form of a program design, the program text, involves retrieving multiple sets of relationships between parts. The research presented here addresses which, if any, abstraction is dominant psychologically in programmers' mental representations of programs, specifically whether procedural (control flow) or functional (goal hierarchy) abstractions dominate, and the relative ease or difficulty of inferring different kinds of information from the text. Eighty professional programmers were tested on comprehension and recognition of short program texts. The results, which suggest that procedural rather than functional units form the basis of expert programmers' mental representations, support work in other areas of text comprehension showing the importance of text structure knowledge in understanding. The results also raise questions concerning claims that "chunking" found in comprehension and memory tasks in skilled problem solving domains is due to pattern matching to schematic content knowledge rather than to knowledge of more abstract text or design sturcture units. A reference list, 4 tables, and 10 figures are appended. (Author/LMO)