After you had your baby, did you feel like your brain went to mush? The exhaustion, stress, and hormonal changes leave so many women feeling like their brain doesn’t work and struggling to remember what happened a minute ago. Well, it turns out that this forgetfulness associated with “Mommy Brain” may actually have a necessary survival function.
A new study published in the journal “Neuron” found that forgetfulness (for anyone, not just moms) could be caused by a safety mechanism in the brain designed to make sure we are not overloaded by too much information. Our brain is set up to flush out unnecessary memories in order to help us survive and thrive.
The two researchers who conducted the study at the University of Toronto in Canada explain that our memory is not for us to convey the most accurate information. Instead, it is meant to help us make smart decisions using the information provided to us. We need our brain to forget irrelevant details so that we can focus on the most useful information that aids in our everyday decision-making.
The researchers came to this assessment after reviewing several previously-published papers analyzing different approaches to memory. Some of these studies looked at the neurobiology of remembering, or persistence, while others looked at the neurobiology of forgetting, or transience. They found significant evidence that there are parts of our brain developed to promote memory loss, which are different from those that store information. A 2016 study, for example, involved scientists who trained mice to find a water maze. The maze location was moved, and then some of the mice were given a drug to help them forget the location of the original maze. The mice that forgot the first round of training located the new maze more quickly.
This new research suggests how a certain level of forgetfulness is designed to make us smarter. The point of memory is to guide us in making decisions – not to remember every detail of every event we experience. The brain actually spends energy causing us to forget information by generating new neurons that overwrite the old ones. As it turns out, memory is not supposed to act like a video recorder, but instead like a list of rules that help us make better decisions. It is productive for us if we forget outdated, irrelevant information that might confuse us or lead us in the wrong direction.
In the report, the researchers outlined two key reasons why we need to forget information. First, it helps us adjust to new situations by letting go of past memories that are no longer needed. Forgetting old information allows us to be more efficient in our lives. Second, it keeps us from generalizing past events to make decisions about new ones. Our brains tend to forget memories of things that happened (episodic memories) more quickly than general knowledge (semantic memories). If we are trying to make decisions and our brain is constantly bringing up details of multiple conflicting memories, it makes it very difficult for us to make choices. Overall, the brain’s goal is to forget everything except those instances that really stand out. This is an amazing process shaped by evolution that has helped us survive as a species.
The researchers also think the amount of forgetting we do could depend on our environment. The faster pace of change results in a faster rate of information-dumping. This is a fascinating finding given our current world of ephemeral tweets, Facebook feeds, and 27/7 news cycles. Think about all the parenting articles you read as a new mom. The more you read, the less you will actually retain. Based on this research, you will only remember the really critical information that you need to help your child.
What does this all mean? Although you may be frustrated that your memory is not as sharp as it once was, and overwhelmed by the abundance of information being thrown at you on a daily basis, your brain is naturally filtering out the information that you truly need to care for your child. Our instincts are taking over so that you can be prepared to quickly react and make decisions as challenges come up.