We act certain ways because of, wait for it...back story. Yeah. Things like:
- How we were raised
- Our parents philosophy on discipline
- Whether or not we had two parents
- What kind of education we had
- How many friends and what sort of friends we had
- Did we see/experience death at an early age
- Did we have to kill someone to protect ourselves or a loved one
- Were we abused
- Did we abuse
- Did we have a pet
- Or not
You can keep listing all kinds of random things, but I think you get the idea. What happened in your character's past helped form their world view and their personality. They have a standard way of reacting to certain stimuli.
The trick as writers is that we must understand all that backstory and the nuances it created in our character without laying it all out for the reader. A well placed line here and there can fulfill the need to understand motivation without writing a complete flashback.
The second trick is keeping it consistent. This isn't to say your character can NEVER do anything abnormal. But if they do, there needs to be a good motivation behind it.
When your characters lie awake at night, what's missing?*
My answer for Talia from The Magic Wakes: peace and hope
What's My Motivation--from one of my favorite author bloggers Janice Hardy. Enough said.
*Determining Character Motivation--by Elana Johnson who quotes Glee: "When you lie awake at night, what's missing?"
The Principles of Character Motivation from Writer's Digest. Sort of a teaser to get you to buy a book. I'm considering it. :)
On Character Motivation--what hooked me to this post is the first sentence: "It has occurred to me that while writing, one of the best things a writer can do is question every action from every character."
Understanding Why Characters Act-- A nice step by step break down of some character motivation from a movie.
The Psychology of Character--"A good writer needs to know both cause and effect, needs to understand that there is impetus behind the actions of his characters. When the writer knows a character’s motivations, she can write actions that make sense for that character in a specific situation."