Why cant we retain all our memories and experiences as we get older?

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Why cant we retain all our memories and experiences as we get older?

In: Biology

I like to look at our brain like a peace of paper. When your born its empty,clean, pretty. Everyday your writing on that peace of paper and it get full. When your old, all the paper has been written on and some sentences cant be read. Its okay be those sentences are there. They existed but just cant be read. You might have spilled coffee over the pages. You can’t read them but you know their there. It must be weird having memory lost.

It’s not so much that we can’t as it is that we don’t have a need to. It has to do mainly with the way our brain stores memories in the first place.

Over millions of years or biology developed a punishment/reward system to drive us to seek things that help us survive and avoid things that inhibit our survival. The positive or negative labeling of memories is a result of this system, and all memories are stored with some type of emotional association.

When we are young many things we experience are new and exciting, and the emotional tags, either positive or negative, are also more intense and varied due to this novelty. As we grow older, however, individual events become less novel because they more often relate to previous experiences and are less likely to be stored in memory as they are less useful in terms of survival.

This doesn’t mean you are unable to remember things as you get older, as there are ways to train your brain to maintain neural plasticity as you age, but due to the fact that you’re not experiencing as many new or intense things, especially not things necessary for survival, your brain has no need to expend the energy required to create long-term memories. Neurons are too costly to make and keep them for no reason.

My psychology teacher said children don’t have the words or vocabulary to “form” memories in their head.

To give as simple an answer as possible, there are two main facts to keep in mind – 1) there’s no survival advantage to storing every single moment of our existence as a memory [e.g. no need to remember the fine details of long, uneventful car rides] and 2) the brain requires tremendous amounts of energy relative to its size to operate (estimated that ~20% of the body’s calorie consumption is used on the brain)

Given these two facts, the brain has developed complex systems that determine what does and does not deserve to get stored. This is in an effort to conserve energy.

This is an incredible over-simplification and there are other theories (related to the brain’s processing power amongst other things), and it’s likely that all of the theories are true to some extent. But I think the simplest and most consequential reason that we don’t store everything as a memory is in an effort to not waste energy.

edit: spelling