Public policy pays surprisingly little attention to evolutionary psychology. Yet there are many human intuitions and behaviors that influence contemporary policy issues -- sometimes in ways that are no longer useful or perhaps even harmful to humans flourishing. These intuitions are sometimes referred to as "folk economics," and one area in which they often emerge is the international economy.
Our primitive ancestors lived in a world that was essentially static; there was little societal or technological change from one generation to the next. This meant that our ancestors lived in a world that was zero sum -- if a particular gain happened to one group of humans, it came at the expense of another.
This is the world our minds evolved to understand. To this day, we often see the gain of some people and assume it has come at the expense of others. Economists have argued for more than two centuries that voluntary trade, whether domestic or international, is positive sum: it benefits both parties, or else the exchange wouldn't occur. Economists have also long argued that the economics of immigration -- immigrants coming here to exchange their labor for money that they then exchange for the products of other people's labor -- is positive sum. Yet our evolutionary intuition is that, because foreign workers gain from trade and immigrant workers gain from joining the U.S. economy, native-born workers must lose. This zero-sum thinking leads us to see trade and immigration as conflict ("trade wars," "immigrant invaders") when trade and immigration actually produce cooperation and mutual benefit, the exact opposite of conflict.
Hat tip: Hit and Run