A new study by a team at the Tilburg University in The Netherlands found that the return trip effect is caused by the different expectations we have, rather than being more familiar with the route on a return journey.
Lead researcher Niels van de Ven said: “People often underestimate how long the outward journey takes and this is therefore experienced as long.”"Based on that feeling, the traveller expects the return journey to be long as well, and this then turns out to be shorter than expected," he was quoted as saying by the Daily Mail. An over-optimistic prior estimation of the journey time leads to the illusion of the return journey being shorter, the researchers said. Their conclusion was based on three short studies where 350 people either took a trip by bus, by bicycle or watched a video of a person taking a bicycle ride.
When the duration estimates were compared, respondents thought that the return journey on an average went by 22% faster than the outward journey. The return trip effect was largest for participants who reported that the initial trip felt disappointingly long. Furthermore, when one group of participants was told that the upcoming trip would seem long, the return trip effect disappeared.
Telling participants that the upcoming trip was going to be very long led them to experience the trip as taking less time. Thus, the study concludes that the return trip effect is based on the expected duration to complete the journey back, which seems a lot less when one expects a longer duration of the journey.