We created clocks and calendars to give people a common way to communicate about the future and the past and about when to have dinner.  But time is, as they say, relative.  A clock on top of a mountain moves differently than one at sea level - that's gravitational time dilation. NIST researchers have even been able to show that tall people age differently than short ones. And if you lived your life in a car traveling 20 miles per hour, you would age slower than people who just walk around. Time is not only relative in physics, it is relative in culture.  We feel like time moves faster the older we get.

Because time is a colloquial concept, the perception of time is the least understood aspect of all.

BBC broadcaster Claudia Hammond has 'investigated' the mysterious world of time perception and will give a talk Wednesday, April 18th, at the British Psychological Society Annual Conference held in London. Hammond, presenter of BBC Radio 4's All in the Mind, will discuss those conundrums like why our lives appear to speed up as we get older, how our minds keep time and why at least a fifth of the population visualize time spread out before them.

Author of Time Warped, releasing May 3rd, Hammond says, "The brain creates its own time, making it remarkably easy to trick the brain's clock. Mind time is different from clock time. It is the inner time we experience and it can pass fast or slowly depending on whether we are waiting for a train, working hard or free falling from a plane. Our relationship with time is not straightforward."

A new hypothesis/speculation/conjecture/wildass guess called the 'Holiday Paradox' will be introduced at the lecture and it seeks to explain why holidays appear to go fast at the time, but when you look back you feel like you were away for ages. Says Hammond: "We judge time prospectively and retrospectively and these two perspectives on time can explain many of its mysteries."

It will also discuss peculiarities like claims about mental time travel and why we remember more events from our late teens and early twenties than from any other time of life - and whether our ability to imagine the future explains the imperfection of our memories.

Attendance is free. Register at www.bps.org.uk/sharingourscience