“It is agreed by both game theorists and evolutionary biologists that the prospects for cooperation are far greater when there is a high expectation of repetition than in single-shot transactions. Clay Shirky has even described social capital as ‘the shadow of the future at a societal scale’. We acquire it as a means of signalling our commitment to long-term, mutually beneficial behaviours, yet some businesses barely consider this at all – procurement, by setting shorter and shorter contract periods, may be unwittingly working to reduce cooperation.”