People often imagine their memories to be like vast libraries, where information is written down, filed away, and then brought back when it’s needed (or lost in some dusty shelf). But the act of remembering is more complicated than that.

Every time we bring back an old memory, we run the risk of changing it. It’s more like opening a document on a computer – the old information enters a surprisingly vulnerable state when it can be edited, overwritten, or even deleted. It takes a while for the memory to become strengthened anew, through a process called reconsolidation. Memories aren’t just written once, but every time we remember them. This might be useful in terms of conquering traumas and phobias, but it’s much less helpful in a courtroom.