Scimex: Return leg of a round trip seems to take less time than the outward journey when recalled in hindsight, even if the actual time taken to travel each way is identical. This assertion has been experimentally confirmed by Japanese scientists using videotaped journeys. They found that people only estimated the return journey as being shorter when they recalled the length after the journey and not at the time of the event - suggesting that it is the feeling of time in retrospect that changes, rather than our immediate perception of time. People reflecting on a roundtrip walk estimated that the return trip took less time than the outward trip, according to a study published June 10, 2015 in the open-access journal PLOS ONE by Ryosuke Ozawa from Kyoto University, and colleagues.
Many have experienced the "return trip effect," where the return trip seems shorter than the outward trip, even when the trips actually took the same amount of time. Scientists have studied the effect, but haven't confirmed its existence in the context of the environment and duration of the real-life trip. To better understand the return trip effect, the authors of this study compared a group of 20 men watching two of three prerecorded walking movies, of either an outbound trip and a return trip or two outbound trips. The participants estimated the length of the two movies both while watching and then again after the two trips.
Only the participants from the group watching an outbound trip and a return trip–a roundtrip–estimated that the second trip took less time than the first trip. Furthermore, the participants felt the return trip effect only when reflecting on length after the trips. By comparing the round-trip condition and the non-round-trip condition, the authors suggest that the return trip on a roundtrip may actually make us feel that time is shorter even without walking, and that the return trip effect may not affect the timing mechanism itself, but rather our feeling of time retrospectively. Further research is needed to better understand the contribution of the awareness of "return," since the labeling such as "roundtrip" or "return" may be another factor in inducing the cognitive bias of the return trip effect.