Arguing that understanding what lies behind the apparent usability of direct manipulation style interfaces might not only help in building better interfaces, but can also draw attention to possible side effects, this paper uses examples from a prototype data manipulation system to pursue a characterization of direct manipulation interfaces as…

Library patrons evaluated two versions of a bibliographic record displayed on cathode ray tube terminal, one representing Library of Congress (LC) format, the other, one of 15 format variations. Patrons generally preferred side heading label and underlining to LC forms, and upper and lower case letters to lower case only. (EJS)