For example, when the US urges German fiscal stimulus – as at it did in Bonn in 1978, in London in 2009, and at the G-20’s Brisbane summit in 2014 – it has in mind the “locomotive game,” in which fiscal stimulus has positive “spillover effects” on its trading partners. The global economy will do better if the major countries – each afraid to undertake fiscal expansion on its own, for fear of worsening its trade balance – agree to act together to pull it out of recession and up to speed.
用博弈论来解释各种协作呼声很有启发，尽管并非是以博弈论专家预想的方式。行动方常常并不认为他们在进行同样的博弈。比如，当美国敦促德国财政刺激时——如1978年在波恩、2009年在伦敦以及2014年在G-20布里斯班峰会上那样——美国想的是“机车博弈”（locomotive game），在这个博弈中，财政刺激对其贸易伙伴有积极的“溢出效应”。如果主要国家——它们都害怕自己采取财政扩张，担心这会恶化贸易平衡——同意采取共同行动让德国走出衰退、加速增长，那么全球经济的表现将有所好转。