Some writers do deep dives in building character backgrounds. They imagine favorite foods, motivation for their tastes in music, preferences on colors and fashion styles, and how they view life. This enables the writer to know exactly how the character will respond in any scene they are put into. Psychological and personal profiles - or backstories are the way for a writer to get to know their characters and then use them appropriately in the story.
I don't work like that. I prefer to write and get to know the characters, seeing where they take me. In my first novel, No Time For Regrets, I had a good idea of who Ruth and Alex were, but had not given a great deal of thought about the other characters. I like to write and see where the characters take the story. I lost several characters from the first draft of that book because they were superfluous. As I tightened the storyline, my remaining characters were forced to carry the weight. Sometimes the story took turns that didn't work. This was particularly evident when I was still learning the characters. As I got to know each of them, their voices emerged. It made sense for Maurine to do this, but not that. Of course, Hannah would say this at this time or take this opinion. She wouldn't do anything else. The characters started working as a team to tell the story. When I sat down to write each day I often did not know where the story was going. I had a big picture plan, but I hadn't plotted out the scenes. I let the characters evolve and do that for me. As I imagined their dialogue and actions, I often felt that I was going where they took me - a roller coaster ride that I thoroughly enjoyed.
In the third book - working title: Carry On Our Dreams, I introduce new characters. I was set to write but the story stalled. It seemed two-dimensional. I kept pushing myself and then realized, I didn't know these new characters. I slowed down my writing and let new scenes marinate. I knew generally where I wanted the story to go. I wasn't sure how to get there, because I didn't know how these characters would behave. As I wrote more, I began to sense their desires, their fears, and their doubts. It puts each character on a chessboard of reactions and actions sparking dialogue and responses of action and words. Sometimes I've had to go back and rewrite because I hadn't listened carefully. I got the characters moving down the storyline but it was empty. Back up, listen again, and let them emerge and tell the story.
It takes time to invent characters and let them emerge. No backstory would help me know what Ruth would say to her granddaughter in a situation that had yet to be developed. No character assessment done in a vacuum could help me know how Reggie would respond to Kate's fears. I have to let my own imagination marinate and select what attributes these characters have and why - as they interact. At least that's my method. To be honest, I start with an understanding of the main characters - spunky, driven, loyal, dreamers, risk-takers, and kick-ass. That becomes the center of gravity around which the other characters exist and the events unfold. I also create the villain or anti-hero who thwarts our heroine. But this character has to be more than the cartoon villain. There has to be some depth and that is revealed as situations arise. The interplay makes all the difference in character development.
In life, we have assumptions about people and use our past experiences to drive our expectations. If someone exhibits these traits, we assume something specific about them. The same is true in developing characters. But the events can create unexpected twists in who these people are and who they become. That's the fun of creating characters.