Just came across this presentation by John Karlin, who worked at Bell Labs back in the mid 1900's, and found it fascinating.

This was the guy who created the "Karlin dot" on rotary phones and helped people dial the phone. The dot gave dialers a spot to aim their finger at, increasing dialing speed (which if you remember rotary phones, was very important, especially if the number had lots of 7's, 8's, and 9's).

Interestingly, now the behavioral economists with their etched flies in urinals think they invented this idea.

Check out John Karlin's speech from 2003. On paper he's an engaging fellow.