The shape influences the effectiveness of the story because it all ties together and makes sense.
The life shape represents the ups and downs of life and as you tell your story you could adjust the shape at high points, low points, or neutral points which will end up giving you your final shape. This shape is also effective because as someone reads your story and sees the shape they would be able to tell how you felt during those times based on looking at the point your life shape is at or heading to. In my opinion the life shape gives the story more life.
As I drew my life shape it was pretty much up and down because thats what my life mainly consisted of, and I know everybodys life shape would be different because we all have different stories and backgrounds which would make it fun to compare your life shape to theirs. The last point I wanted to make is that some people are closed people who wouldn't really want to open up about their life but if they were to draw a life shape In my opinion would tell a lot about the person just by observing it knowing they would not open up to you.
All in all I think a life shape speaks for itself in a more closed kind of way opposed to actually telling your life story in depth.
Tajierre Rudolph