Making your way gloomily to the airport after an action-packed holiday, it is easy to feel the days have flown by all too quickly. But there is no need to worry because once you return to the daily grind your break will suddenly seem like it lasted for a lifetime.

So say psychologists who believe that the effect is down to the different methods the brain uses to judge the passage of time. Learning to manipulate our perception of time could make our lives feel fuller and reassure those who feel that the years slip by faster as they grow older.

The mystery behind the so-called "holiday paradox" was explained in a presentation by psychologist and BBC broadcaster Claudia Hammond at the British Psychological Society conference in London last week. Ms Hammond, whose book Time Warped will be published next month, said when we are doing something new and interesting – such as when we are on holiday – time appears to go more quickly than when we are bored or anxious.

In a normal fortnight the average person only accumulates between six and nine new memories because so much of what we do is routine.But on a holiday we can build up that number of memories in a single day because everything we experience is new, meaning that when we look back it will seem to have lasted much longer than it really did.

She said: "The same happens as we get older and time starts to speed up. There are fewer memories of new things, and we do the same things more and more often."

People who complain that years seem to whizz past with increasing speed could slow things down by making the most of their weekends and breaking up their daily routine, she added. "Taking a different route to work, getting off your bus a stop early or avoiding having the same sandwich for lunch every day could make life seem a little slower," she said.