Cahill, M.-C. (1975). Interpretability of graphic symbols as a function of context and experience factors. Journal of Applied Psychology, 60, 376-380.

Ten of the graphic symbols designed by Henry Dreyfuss Associates for Deere and Company farm and industrial machinery were tested for ease of interpretation in context and in isolation. Subjects were mechanical engineering students (N = 30) who differed in their extent of familiarity with such equipment. As hypothesized, the symbols were more often correctly identified in context and by subjects with relevant prior experience. Symbols maintained the same relative order of difficulty under both context and no-context conditions, a difficulty which ranged from 100% correct responses to only a few correct responses. It was concluded that empirical validation of effectiveness is a necessary, although often neglected, step in the symbol development process.