Textbook of Usability

1912 to 1965, USA · Experimental psychologist; founder of engineering psychology

Also known as: Paul M. Fitts, P. M. Fitts

Paul Morris Fitts spent the Second World War studying aviation accidents for the United States Army Air Forces, and his 1947 report on pilot errors with confusing cockpit controls is the foundational document of human factors engineering. He showed that crashes blamed on "pilot error" were predictable consequences of incompatible knob shapes, inconsistent control layouts and ambiguous displays, and that the design of the aircraft, not the training of the pilot, was where the problem could be solved.

His 1954 paper The information capacity of the human motor system in controlling the amplitude of movement introduced what we now call Fitts's Law: the time to move to a target is a logarithmic function of the distance to the target divided by the target's width. The law has been replicated across mice, touchscreens, eye-tracking, the foot, the head and the wheelchair joystick, and has held with remarkable precision for seventy years. It is the closest thing in human-computer interaction to a physical law and underwrites the design of every modern pointing device and interface.

Fitts also developed the Fitts list of functions humans do better than machines and vice versa, a framework that still informs decisions about automation. He died at fifty-three, but his work has continued to define the quantitative side of usability.