Scientists carried out an experiment to explore the reasons why we feel that time slows down in times of danger/fear.

They concluded that it’s because the brain stores more information about these intense and previously unexperienced events than banal, unremarkable events, and therefore they seem to have lasted longer in hindsight.

They say the same goes for our perception that time seems to fly by much faster for adults than for children: Everything is new for children and so they have much more densely built memories.

Read the article here