thinking
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The inability to remember has long been considered a failure of the brain, but a new study has found that our brains are actively working to forget memories in order to retain the truly important information.

In fact, the study's researchers believe the brain is not designed to keep memories intact, but its actual purpose is to only hold onto valuable information to optimize intelligent decision making over time.

"It's important that the brain forgets irrelevant details and instead focuses on the stuff that's going to help make decisions in the real world," says Blake Richards, author of the study and associate fellow in the Learning in Machines and Brains program.

The new University of Toronto paper was published Wednesday in the Neuron journal. Paul Frankland, a senior fellow at CIFAR's Child & Brain Development program, who was also involved in the study, says,"We find plenty of evidence from recent research that there are mechanisms that promote memory loss, and that these are distinct from those involved in storing information."

One of those mechanisms is the weakening of synaptic connections between neurons, in which memories are encoded, reports Medical Xpress. Another is the creation of new neurons, which overwrite stored memories and could explain why children (who produce a significant amount of new neurons) forget more than adults.

The pair's research into the brain's persistence (remembering) and transience (forgetting) found forgetting is just as important as remembering for two reasons:

One, forgetting allows the brain to let go of outdated or incorrect information making it easier to adapt to and decipher new problems.

"If you're trying to navigate the world and your brain is constantly bringing up multiple conflicting memories, that makes it harder for you to make an informed decision," says Richards.

And two, it simplifies your memories, basically creating a streamlined computer of information in your brain so you can take the crucial information from a certain event, rather than specific details, and frees up more room for important information.

"One of the things that distinguishes an environment where you're going to want to remember stuff versus an environment where you want to forget stuff is this question of how consistent the environment is and how likely things are to come back into your life," says Richards.

For example, someone who meets new people every day is likely to forget the details of each exchange, whilst someone who talks to the same people on a day-to-day basis is likely to hold on to information longer.