I can’t remember! Its to do with being able to store and recall information and to do that we often associate it with a clue or trigger. Find the right trigger and you will recall the information. Sometimes this storage process goes wrong to finding it again is more difficult in the brain. With practice you can improve your memory too which is quite neat.
First your memories are stored in the short term memory stored in your cerebral cortex. Then over time, they are converted to long term memories by the hippocampus. The hippocampus sorts them into 2 categories: procedural memory and declarative memory. Procedural memory is things that you learn sub-consciously like learning to ride a bike. Declarative memory is when you can recall facts and events. I guess when you are busy or stressed, it is easy to forget the short term stuff, and I suppose when the hippocampus is sorting out the memories, maybe it decides which ones are important or not. Sleeping is supposed to help with the consolidation of memeories so maybe if you haven’t been sleeping well, you may also find it hard to remember things.
Memory loss is also caused by damage to the brain as a result of an injury and this condition is called amnesia.