Alphonse Chapanis is best known as a founding father of human factors engineering and ergonomics. He pioneered the application of psychological research on vision and perception to engineering design. His most famous contribution was his World War II work on shape coding in aircraft cockpits, where he solved a critical safety issue by differentiating identical controls for landing gear and flaps, which had been causing fatal crashes. He also co-authored the first textbook on the subject in 1949, 'Applied Experimental Psychology: Human Factors in Engineering Design,' which established the discipline's foundation.

During World War II, Chapanis was the first psychologist assigned to the Army Air Force Aero Medical Lab. He investigated a series of B-17 crashes during landing and discovered that pilots were confusing the identical switches for the landing flaps and landing gear, which were placed side by side. He proposed attaching a wheel-shaped knob to the landing gear control and a triangular knob to the flaps control. This simple shape-coding innovation allowed pilots to distinguish the controls by touch alone, and after its implementation, there were no further instances of this particular error.

Chapanis's most important book is 'Applied Experimental Psychology: Human Factors in Engineering Design,' co-authored with Wendell R. Garner and Clifford T. Morgan and published in 1949. It is widely recognized as the first textbook on human factors and ergonomics. The book emerged from a series of lectures on 'Men and Machines' given at the U.S. Naval Academy. It established the new discipline's name and framework, marrying applied psychological research with equipment and system design, and it remains a landmark publication in the field.

Beyond aviation, Chapanis made significant contributions to the design of everyday technology. In the 1950s, he worked with Bell Labs on the design of the push-button telephone, conducting experiments that led to the present layout of the keys. He also pioneered research on multimodal communication, demonstrating that including an interactive speech mode always improved performance in human-computer interaction. He authored over 170 articles and 6 books, served as president of the International Ergonomics Association, and trained a generation of human factors professionals at Johns Hopkins University.

Alphonse Chapanis was born in Meriden, Connecticut, on March 17, 1917. He completed his graduate training at Yale University, where he received his PhD in Psychology in 1943. He spent World War II as a research psychologist at the Army Air Force Aero Medical Lab in Dayton, Ohio. In 1946, he joined Johns Hopkins University's Systems Research Laboratory, moving to its Baltimore campus in 1948. He remained at Johns Hopkins for over 35 years until his retirement as professor emeritus in 1982.

Chapanis received significant recognition for his contributions to the field. He was a Fellow of the American Psychological Association and served as president of its Division 21 (Society for Engineering Psychologists). He was also president of the Human Factors Society and the International Ergonomics Association (IEA), serving the latter from 1976 to 1979. He was awarded the title of CHFP (Certified Human Factors Professional). His professional autobiography, 'The Chapanis Chronicles,' documents his 50 years of human factors research, education, and design. His legacy is commemorated through his lasting impact on the discipline and its institutions.

Chapanis's work laid the intellectual and practical foundation for modern human factors psychology. By demonstrating that psychological principles could be systematically applied to engineering design, he established the discipline as a distinct field. His shape-coding solution for aircraft controls set a precedent for user-centered design and safety standards in aviation. His research on multimodal communication foreshadowed the importance of user experience in digital interfaces. His textbook became the template for human factors education. Through his teaching, consulting, and leadership in professional organizations, he institutionalized the practice of designing technology around human capabilities and limitations.

Shape coding is a design principle where controls or components are given distinct physical shapes to allow them to be identified by touch alone, without requiring visual confirmation. Chapanis pioneered this concept during World War II when he attached a wheel-shaped knob to the landing gear control and a triangular knob to the flaps control in B-17 aircraft. This simple innovation prevented pilots from confusing the two controls in high-stress situations, eliminating a specific cause of crashes. Shape coding remains a fundamental principle in human factors engineering and is still regulated for use in civil aircraft cockpits, demonstrating the enduring value of Chapanis's insight.