By all accounts a modest man despite his variegated accomplishments (he had a doctorate in mathematical psychology, was trained in electrical engineering and had been a professional violinist), Mr. Karlin, who died on Jan. 28, at 94, was virtually unknown to the general public.
But his research, along with that of his subordinates, quietly yet emphatically defined the experience of using the telephone in the mid-20th century and afterward, from ushering in all-digit dialing to casting the shape of the keypad on touch-tone phones. And that keypad, in turn, would inform the design of a spate of other everyday objects.
An early experiment involved the telephone cord. In the postwar years, the copper used inside the cords remained scarce. Telephone company executives wondered whether the standard cord, then about three feet long, might be shortened. Mr. Karlin’s staff stole into colleagues’ offices every three days and covertly shortened their phone cords, an inch at time. No one noticed, they found, until the cords had lost an entire foot.
From then on, phones came with shorter cords.
Mr. Karlin also introduced the white dot inside each finger hole that was a fixture of rotary phones in later years. After the phone was redesigned at midcentury, with the letters and numbers moved outside the finger holes, users, to AT&T’s bewilderment, could no longer dial as quickly.
With blank space at the center of the holes, Mr. Karlin found, callers no longer had a target at which to aim their fingers. The dot restored the speed.
Interesting stuff - read the whole thing.