Next time you mislay your keys, can’t recall basic O-level history or find yourself in trouble again on your wedding anniversary, don’t blame old age — blame your brain’s evolved mechanisms for neuronal transience.

Scientists have claimed that forgetting things may not always imply you are scatterbrained. Instead, it could be crucial to coping with new challenges.

“We think an important part of being intelligent is about forgetting the details of past experiences,” Blake Richards, of the University of Toronto, said. He and a colleague argue in the journal Neuron that things you forget are as important for brain efficiency as those you remember. As a consequence, the brain actively promotes forgetting.

Traditionally, brain scientists have focused on studying the mechanisms behind memory formation; forgetting