The Sentiment Cycle applied to the SPX chart

I picked up this book a while ago at half priced books called 'The Nature of Risk, Stock Market Survival, and The Meaning of Life' by Justin Mamis. He came up with something called the "Sentiment Loop". Here's a picture of it from his book.



So I pulled up the SPX 6 month chart and made a little comparison, the similarities will blow your mind:

Strikingly similar, yes? Of course, this is out of a trading book from 1999, before traders bowed down to the algorithm overlords. But it will be interesting to see if this plays out.