Ever felt like a journey was shorter on the way back compared with when you were heading out to your destination? That's called the "return trip effect" and researchers have found what could possibly be causing it.

In a study published in the journal PLOS One, Ryosuke Ozawa, Keisuke Fujii and Motoki Kouzaki detailed how they were able to get to the bottom of the return trip effect, pointing out that the effect is manufactured by the memories a traveler has of their journey. Though the effect leads to a feeling that time passed more quickly, time itself was not affected.

For the study, Ozawa and colleagues had 20 healthy men, 20 to 30 years of age, watch films made using footage captured via a camera strapped to the chest of someone walking two different routes. Half of the subjects were assigned the outbound and return trips using a single route while the other half were given videos of two different routes shot in separate locations.

All the videos were about 26 minutes long and were viewed with the subjects seated on chairs. The study's participants were then asked to notify the researchers each time they believed three minutes had elapsed, without being given access to clocks. A questionnaire was also to be filled out at the end of watching the movies to determine if one trip was perceived as taking longer compared with the other.

After analyzing the results, the researchers suggested that return trips may feel shorter because the return trip effect is affected by the traveler's retrospective feeling of time.

Niels van de Ven from the Netherlands' Tilburg University has been studying the return trip effect as well and though not involved with the current study being discussed, he believes it supports his own findings that the effect is guided by expectations.

"When heading back we think, 'It's going to take a long time again,' after which it feels not as bad," he explained.

Van de Ven also speculated that it's possible the return trip effect exists simply because people think it does, which makes them respond accordingly.

Ozawa and colleagues are looking to do further research to gain a better understanding of what it means to be aware of "returning," as labeling trips as "return" or "round-trip" may have a hand in inducing cognitive bias that creates the return trip effect.

Photo: Mike Lewinski | Flickr