Character charts helped me understand character and characterization when I began writing seriously. Later, Robin Perini's and Laura Baker's Discovering Story Magic method helped me get a handle on character strengths and flaws, and I still reference her work. After years of study and practice, my characters grow more organically in conjunction with plot.
Although my stories include characters with identity issues, those issues don't always relate to one traumatic childhood experience—although there’s nothing wrong with creating straightforward characters (see Terri Molina's post .) For example, my heroine Meg is a very good girl who served time in prison for trying to kill a man with a manure shovel (Very Traumatic Experience, and a choice that, in her mind, defined her.) But her relationships with men before and after that trauma are shadowed by her father’s death when she was a little girl (Different Trauma.)
One could argue that Meg’s traumas are somehow connected, but my take is that character is a gestalt of innate gifts/tendencies, traumas, nurturing experiences (or a lack thereof) and free will. Free will allows a character to choose what they become, because there are always choices.
The character Dexter in the television drama of the same name is a good example of what I mean. He’s a seriously messed-up guy—a serial killer. But he was raised in a nurturing family and has a father he respects, who is a cop. He chooses to try to redeem himself from what he knows are his evil ways by killing only other bad guys. He could choose to give in to his violent urges without thought, or he could choose to check himself into a hospital for the criminally insane, or he could choose to do what he does, or…whatever. The point is there are always choices. Even not choosing is a choice.
Dexter’s choices are based on an amalgam of his innate characteristics and his life experiences and relationships, to the point that issues of cause and effect, motivation and goal, are blurred. That’s what makes him a fascinating and complex (if repugnant) character. As the popularity of the show demonstrates, people empathize with him (although I couldn't get past the fact that he was a serial killer.)
Good-girl-cum-attempted-murderer Meg can choose to live her life in her current ex-con mindset; or she can pretend she never tried to kill a man and hasn't changed at all; or she can accept responsibility for the past, forgive herself, and choose the future self she wants to be. This movement in character propelled by the choices a character makes throughout a story is known as the character's arc.
At the beginning of my story when Meg, in her ex-con mindset, finds the body of the man she once tried to kill dumped on her property, do you think she calls the police right away or moves the body to avoid suspicion? Do you think after going through her character arc she’d do the same thing at the end of the story?