As we get older, time seems to pass more rapidly. Many people recall long hours and days during their childhood, when time seemed to pass at a painfully slow pace.

But as years pass and our lives become filled with activities and responsibilities, time seems to race.

When studied objectively, however, such age effects are not always observed. Dr. Marc Wittmann of the Institute for Frontier Areas of Psychology and Mental Health in Germany systematically studied 499 volunteers aged 14 to 94 and found few age-related effects on time perception — except for their insight on 10-year time intervals.

Older volunteers reported that their previous decade seemed to have passed more rapidly.

Another explanation for age differences in time perception is that while we’re forming new memories, time seems to slow down.

Dr. David Eagleman of Baylor College of Medicine found that new cognitive stimuli slow down our perception of time more than repeated, familiar stimuli.

French psychology professor Sylvie Droit-Volet found that depressed patients experience time slowing. Her studies also indicate that when we experience fear, our perception of time slows down.

This research suggests that minimizing stress and engaging in lifelong learning are strategies that can make our lives seem longer.