Document 5Lwj91k8o3zK086DdZX9QYxkz

Human Factors Engineering Fig 5-14 --Top Shape Coding Two sets of knobs for levers that are distinguishable by touch alone Bottom Texture coding Ten texture codings that can be distinguished Courtesy Department of the Air Force, Wnght-Patterson AFB Top W O Jenkins, Psychological Research on Equip ment Design Research Report 19, 1947 Bottom J V Bradley, Tactual Coding of Cylindrical Knobs, Tech Report 59-182 1959 to nearly everyone in the population Some examples are given in Fig 5-13 Any display-response that calls for a move ment contrary to the established stereotype is bound to produce errors The designer is calling for'errors by asking the operator to change, in this or that unique situation, a be havior pattern that can be described as habit If an operator misreads a poorly designed display and operates the wrong control or the right control in the wrong direction, safety may be jeopardized, and the system effective ness degraded, if not lost entirely Despite the fact that many accident reports would classify this as an "unsafe act" or hu man error, it is, in fact, a design error Re- 116