Today's Edition: Backstory in Memoir
Think about your favorite contemporary novels or non-famous-person memoirs (classic literature should not be included in this thought experiment – writers and readers in days gone by could get away with all sorts of things that our modern readers will not stand for). Do you know everything there is to know about every character's history? Where they were born? What their parents were like? If it is a story with an adult protagonist, you may know a few details as they pop up in the general narrative, but you most likely don't have chapters devoted to the past.
It is very difficult to cut our own pasts out of our memoirs. You know that your past made you who you are today, and you probably have very strong opinions on how certain things affected you. And you want your reader to understand you as a person, so you feel that you have to include everything.
Don't. Like a fiction writer, you know everything there is to know about your protagonist (you). But you don't include it all. So much about a person is under the surface – we only ever see the tip of the iceberg – but if you show us the iceberg, if you really let us come up close and see the tip, we'll know that there is more below the surface. When it comes down to it, the way that your characters speak, the way they behave, the way they interact with each other and react to the events happening to them in the present of the story will mean so much more to the reader than anything you tell them about your characters' past.
And backstory isn't just limited to telling us about the past – too much background included in a scene or "explaining" can be just as detrimental to your story. One of the great joys of reading a book is finding the connections between events, discovering the motivations of the characters, and using our own experiences and understanding of the world to understand the characters and their actions. If you constantly spell out for us why someone did something, or that this means that this will happen, or that happened because of this other thing, you lose the joy of discovery and the power of whatever is happening in the moment. You are telling the reader far too much – if you're doing this, you'll find notes such as "essaying" and "pontificating" and "over-explaining" throughout the marked MS. When you are essaying, you're telling us too much instead of letting us just live it and discover it with you. Find your moment, stay with it, and trust the reader to find his or her own connections.