Why the Other Line Always Moves Faster

Few everyday experiences are as reliably irritating as joining a line at the supermarket, only to watch the one beside it glide forward while yours stands perfectly still. Most of us conclude that we are simply unlucky. There is, however, a less personal explanation, and it begins with a piece of arithmetic: if you are standing in one of three lines, the chances are two in three that at least one of the others will move faster than yours. Merely by choosing, you have made it likely that you will lose.

Arithmetic, though, accounts for only part of our frustration. In 1985, David Maister, an expert on the management of service businesses, published an essay called "The Psychology of Waiting Lines", in which he argued that the way a wait feels has surprisingly little to do with how long it actually lasts. He proposed several principles. Time spent doing something feels shorter than time spent doing nothing, and anxiety makes a wait seem longer. A wait of unknown length feels longer than a known, finite one, and a wait that nobody explains feels longer than one that is explained. Crucially, an unfair wait feels longer than a fair one.

It is the last of these that matters most at the supermarket. Standing in a line, we do not merely wait; we compare. Every time someone who arrived after us is served first, we register it as a small injustice, and that sense of unfairness stretches the minutes. This helps to explain why so many banks and airports prefer a single line feeding several counters: the total wait may be no shorter, but since nobody can be overtaken, nobody feels cheated.

The value of keeping people busy is illustrated by a story that The New York Times reported in 2012. According to the Times, passengers at an airport in Houston had been complaining about the long wait for their luggage, so the airport hired more baggage handlers, and the average wait fell to eight minutes. The complaints continued. When the problem was analyzed, it turned out that passengers spent about a minute walking from their gate to baggage claim and roughly seven more standing by the carousel with nothing to do. The solution was not to deliver the bags any faster, but to make the walk longer: arriving flights were moved to gates further from the main terminal, and the bags were sent to the most distant carousel. Passengers now spent most of those minutes walking rather than standing, and complaints fell almost to zero.

Had the airport simply tried to shorten the wait even further, it might have spent a fortune for very little gain. What Maister's principles suggest is that the cheapest way to improve a wait is often to change how it feels rather than how long it lasts, and his essay includes an elegant example. At a hotel whose guests kept complaining about slow elevators, mirrors were installed near the place where guests waited. With something to look at, mostly themselves, the guests complained far less, even though the elevators were exactly as slow as before.