In 1969, astronaut Alan Bean went to the moon as the lunar module pilot on Apollo 12. Although the trip going to the moon covered the same distance as the trip back, "returning from the moon seemed much shorter," Bean says.
People will often feel a return trip took less time than the same outbound journey, even though it didn't. In the case of Apollo 12, the trip back from the moon really did take somewhat less time. But the point remains that this so-called "return trip effect" is a very real psychological phenomenon, and now a new scientific study provides an explanation.
Niels van de Ven, a psychologist at Tilburg University in the Netherlands, says the conventional wisdom is the trip back seems shorter because it's more familiar, so people recognize landmarks. "And that might help to increase the feeling of speed, of how fast you travel," he says.
But that didn't seem right to him. "When I take, for example, an airplane, I also have this feeling, and I don't recognize anything on my way, of course. When I look out of the window, I don't see something I recognize," van de Ven says.
So he decided to do some experiments exploring that feeling. One involved people who were planning to ride their bikes to a fair. He asked each person to ride the same route to the fair. Then he split the participants into two groups. He asked the riders in one group to come home by the exact same route. For the other group, he mapped out a different route, but one that was the exact same length. If the familiarity explanation was right, only the group travelling home by the same route should feel that the trip home was shorter.
When he did the experiment, he found the route didn't matter. Both groups had the same feeling that the return trip was shorter.
Here's what van de Ven thinks is going on: "Often we see that people are too optimistic when they start to travel," he says. So when they finish the outbound trip, they feel like it took longer than they expected. That feeling of pessimism carries over to when they're ready to return home. "So you start the return journey, and you think, 'Wow, this is going to take a long time.'"
But just as initial optimism made the trip out feel longer than expected, this pessimism starting back makes the trip home feel shorter.
"It's really all about your expectations — what you think coming in," says Michael Roy, a psychologist at Elizabethtown College and a co-author with van de Ven on the article describing this effect in the journal Psychonomic Bulletin and Review.
Roy doubts all psychologists will agree with their conclusion that expectation is an important cause of the trip home effect. "But ... we're not saying this is the only cause. There are definitely likely other causes as well," he says.
In fact, there are psychologists who agree with astronaut Bean that the trip home seems shorter because there's less pressure to reach the intended target on time.
"When you have a destination you want to be there on time," wrote Richard A. Block, a psychologist at Montana State University, in an email. "But when you go back home (return trip) it does not matter that much. Thus, when you are going there, your attention is more focused on the target and not distracted." In this case, being distracted makes the trip seem shorter.
It's true that the return home effect is just an illusion, and a better understanding of it might make it go away. But van de Ven says that might not be a good idea.
"In the end, this return trip effect gives you a positive feeling once you get home, so I'm not sure whether you want it to go away."