Originally published in the AppleDirect, August, 1989. Republished as Chapter 6, in Tog on Interface:

While the keyboard users in this case feels as though they have gained two seconds over the mouse users, the opposite is really the case. Because while the keyboard users have been engaged in a process so fascinating that they have experienced amnesia, the mouse users have been so disengaged that they have been able to continue thinking about the task they are trying to accomplish. They have not had to set their task aside to think about or remember abstract symbols. Hence, users achieve a significant productivity increase with the mouse in spite of their subjective experience.

What an interesting read about how computing commands were shaped.