four distinct turning points between those brain phases in an average brain: at ages 9, 32, 66 and 83. .

  This is one of the reasons why I see my own life as being different people in the same body as I have aged  because we perceive ourselves differently at different phases of life and how we perceive everyone around us too.

However, I remember being 10 years old and when I think of the kindly sort of scientific outdoorsy kind of person I was then I am basically the same person now except with much more knowledge, wisdom and psychological armor so I can better survive everything in life than at age 9.

So, these phases of 9, 32, 66 and 83 make a lot of sense to me because of my being 77 years old at present. 

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Human brains have 5 distinct 'epochs' in a lifetime, study finds

For the first time, scientists say they’ve identified four distinct turning points between those phases in an average brain: at ages 9, 32, 66 and 83. During each epoch between those years, our brains show markedly different characteristics in brain architecture, they say.