Question: Do we ever completely forget things or are they just 'buried'?

Helen O'Connor answered on 24 Jun 2011:

Psychologists have found that sometimes when we think we have forgotten something it is still there in our memory but we just can’t remember it as we don’t have a good way of finding it (imagine having lots of files in a cupboard, but they aren’t labelled properly so you can’t find easily where anything is). But we also think that there is some information that we forget or “lose” permanently from our memories.

We can forget information in three ways:

1. Decay: when we don’t use that information much, so it just fades over time. Like when you memorise something for an exam (like the periodic table) and you know if off by heart because you practice so much. Then, try to remember it 5 years later, you might not because you haven’t practiced it every day like you did when you were revising.

2. Displacement: we forget old information when new information enters our memory. So if a friend changes their phone number, you remember the new one and that makes you forget the old one.

3. Interference: this is when it becomes difficult to remember information if you’ve been trying to memorise similar things. So you are revising three different periods in history, and they kind of blur together because they are quite similar.

With illnesses such as dementia people stop being able to remember things that happened recently although they often still remember things that happened a long time ago.