There are several criticisms I have to offer for this model.
First, you are statistically underpowered with the number of events/periods you mention, in fact you only mention 900AD, 1200AD, 1500AD, 1800AD… that is 4 data points.
Second, you provide no empirical evidence for you claims. What parameters did you use to assess that 1200AD was left, while 900AD was right? You are heavily biased by (already biased) historical datasets and cherry-picking whatever you assume fits the picture. Usually, any scientist would go the other way round; propose parameters to test and look how they change over time. These parameters could be: Social inequality and wealth distribution. Education and literacy levels. Religious affiliations. Food production and startvation, deaths from disease/war/starvation as based on % total population… you get my point. With no definied parameters, there is no modeling.
Third, you only focus on western civilizations without giving reason as to why not considering others. If this “pendulum” theory should hold any traction on the human condition, that you would need to observe it in al human civilizations.
Forth; why arbitrarily choose a 300 year timeframe? Because it fits you biased narrative of events? How do you estimate what events are right brain/left brain driven and how do you ensure inclusiveness of all events throughout the ages? More importantly, what would be the mechanistic cause of this right/left brain shift, given that it takes hundreds of years spanning several generation of lifetimes of ordinary humans that are not related to each other, neither socially nor genetically.
Fifths, you are lacking a definition of right brain/left brain that is coherent with today’s neuroscience; you took over an old model of the brain researchers made up at a time the had nothing better, but now the scientific view on the brain is way more nuanced and sophisticated.
There is way more to criticize, but I’ll leave you to address these five points first. At the moment, this is a convoluted conspiracy-theory you pulled out of your arse and way more likely to be produced by a brain that is all-too-prone to find patterns where none exist.
For this model to be considered seriously, it would need extraordinary evidence, yet you fail to even provide rudimentary parameters on which to test it.
I encourage creativity, but if you put idea’s out there as if they had any truth attached to them, they need to be criticized.
We already have enough people living in a fantasy reality because they can not discern fact from fiction any more
So please, for further discussions of your ideas, make a disclaimer that there is no scientific study conducted to confirm any of your assertions nor is their a scientific consensus on any claims you make about the past and it’s implications for the future.
That all being said, there is actually a field in science called Cliodynamics, and real scientists are working on trying to understand the past to be able to make predictions about the future. You can have a look here: