John Karlin knew how long a telephone cord should be and in what order the buttons should go on push button phones.
[when]the dial gave way to push buttons, new questions arose: round buttons, or square? How big should they be? Most crucially, how should they be arrayed? In a circle? A rectangle? An arc?
For decades after World War II, these questions were studied by a group of social scientists and engineers in New Jersey led by one man, a Bell Labs industrial psychologist named John E. Karlin…
In 2013, the 50th anniversary of the introduction of the touch-tone phone, the answers to those questions remain palpable at the press of a button. The rectangular design of the keypad, the shape of its buttons and the position of the numbers — with “1-2-3” on the top row instead of the bottom, as on a calculator — all sprang from empirical research conducted or overseen by Mr. Karlin.
The legacy of that research now extends far beyond the telephone: the keypad design Mr. Karlin shepherded into being has become the international standard on objects as diverse as A.T.M.’s, gas pumps, door locks, vending machines and medical equipment.