If you don’t have enough of something – money, say, or time – fixating on it could make the problem worse
When you next find yourself waiting in a horrendously long queue, you could kill time by contemplating this surprising finding from “queueing theory”, a sub-branch of mathematics which is exactly as it sounds. This particular example comes from the mathematician John Cook; I found it via kottke.org. Suppose there’s a bank with only one staff member on duty, spending 10 minutes with each customer. Customers join the queue randomly, on average once every 10.3 minutes. What’s the average wait time? If you let the situation run and run, eventually it’ll reach a “steady state” of five hours of waiting. Add one more staff member, and that falls to three minutes. To be fair, in the real world, no bank would be open long enough for things to reach that point. But the lesson is clear: having even a little slack in the system isn’t merely helpful. It makes all the difference in the world.
What goes for bank queues goes for human lives, too: having no slack, whether of time or money, is an even bigger drawback than you might have thought. In their book Scarcity, behavioural scientists Eldar Shafir and Sendhil Mullainathan show that “scarcity captures the mind”. When you don’t have enough of something, you fixate on it, so it occupies much more mental bandwidth. If you’re not sure you’ll have enough money to feed your family all this month, you have an obvious problem, but also a non-obvious one: the toll on your mental resources, research suggests, will undermine your ability to make wise spending decisions, damaging your chances of escaping your predicament.