Question: Why do some of your thoughts not go to your long term?

Alex Reid answered on 13 Nov 2018:

Hi thank you for the question. Forgetting is a really important part of memory. Your brain is generally geared towards your future survival, and to do this it wants to build a collection of memories that are both relevant and useful! Not everything you learn is needed in the future (imagine storing every single detail about everything!). Storing all memories might gunk up your memory systems and make it harder to prioritize the memories that are genuinely important (such as how to cross the road safely to avoid getting squashed by a car!). Some information might also go out of date. Say you had to make a new password for your email, it would be best to ‘forget’ your old one as quickly as possible or else you might keep typing it in! As an analogy, imagine your memory is a shrub you are entering into a garden competition. Rampant growth would make the shrub look scruffy and would not serve the purpose of winning the competition. By trimming the shrub in the right way, it makes it a lot more likely to win.