In 1972 American industrial designer Henry Dreyfuss (March 2, 1904 – October 5, 1972) published The Symbol Sourcebook, A Comprehensive Guide to International Graphic Symbols.
“A ready reference aid and an inspiration to designers . All in all the best book now available on symbols.” –Library Journal.
This visual database of over 20,000 symbols provided a standard for industrial designers around the world. He included a section of 60 hobo signs, used by ‘transient working class men and women who traveled by train to communicate with one another in the Great Depression, late nineteenth and early twentieth century.
“This unparalleled reference represents a major achievement in the field of graphic design. Famed industrial designer Henry Dreyfuss recognized the importance of symbols in communicating more quickly and effectively; for many years he and his staff collected and codified graphic symbols as they are used in all walks of life throughout the world. The result is this “dictionary” of universally used graphic symbols. Henry Dreyfuss designed this sourcebook to be as practical and easy to use as possible by arranging the symbol information within ingeniously devised sections: Basic Symbols represents a concise and highly selective grouping of symbols common to all disciplines (on-off, up-down, etc.).
Disciplines provides symbols used in accommodations and travel, agriculture, architecture, business, communications, engineering, photography, sports, safety, traffic controls, and many other areas. Color lists the meanings of each of the colors in various worldwide applications and cultures. Graphic Form displays symbols from all disciplines grouped according to form (squares, circles, arrows, human figures, etc.) creating a unique way to identify a symbol out of context, as well as giving designers a frame of reference for developing new symbols.”
Jules J. Wanderer noted in his 2001 paper ‘Embodiments of bilateral asymmetry and danger in hobo signs’ one way these signs worked was by tapping into the American brain’s natural bias for right over left:
“For example, paths, roads, or trails were not marked with words indicating they were ‘preferred directions’ to travel or places to be ‘avoided.’ Instead objects were marked with hobo signs that discursively differentiate paths and roads by representing them in terms of bilateral asymmetry, with right-handed directions, as convention dictates, preferred over those to the left.”