For the real world anekdote, all successful businesses that i worked with seem to be tit-for-tat-ers
An apparent counter-example (Goldman Sachs): http://www.nytimes.com/2012/03/17/opinion/nocera-the-good-bad-and-ugly-of-capitalism.html?_r=2
An apparent counter-example (Goldman Sachs): http://www.nytimes.com/2012/03/17/opinion/nocera-the-good-bad-and-ugly-of-capitalism.html?_r=2