The cognitive niche: Coevolution of intelligence,
sociality, and language.
by Steven Pinker. pdf 
Pinker suggests how two simple mechanisms could account for the coevolution of intelligence, sociality, and language. From the abstract, he says: "The second hypothesis is that humans possess an ability of metaphorical abstraction, which allows them to coopt faculties that originally evolved for physical problem-solving and social coordination, apply them to abstract subject matter, and combine them productively." I found it a great read and am happy to see he cites papers I have found provocative, especially [62]. Of course I think programming computers to be one of the most profound extensions of the human intellect. Careful incorporation of metaphor then becomes our responsibility.
To softwaremetaphor@googlegroups.com. June 5, 2011.