Imagine there is a disaster occurring in a city 5 miles away, and in your state, and there is a risk of the disaster spreading. Now imagine the disaster is occurring in a city 5 miles away, but in a different state. Which disaster is more dangerous?
A study finds that people think of borders as physical barriers that can keep disasters at bay. We are more concerned about a disaster approaching us from within a state and less concerned about a disaster spreading from a different state - even if the disasters are the same distance away. Somehow, a disaster occurring in a different state is seen as less severe. People feel even more protected when the border lines on a map are made darker. Nice thick borders make all the difference.
One easy answer to the whole current caravan hysteria is a law that requires all maps to have a really thick and dark border drawn between the US and Mexico. The troops can go home. Problem solved.