The right hemisphere serves up to the left hemisphere a pre-cognitive purchase on the world. In effect, the left hemisphere is always receiving gifts from the right hemisphere while it is rarely able to acknowledge those gifts.
By ratcheting up the threat level that people experience it is possible, on a mass scale, to shift people's consciousness from the right hemisphere to the left. Within the left hemisphere people have trouble recognizing false premises. People tend to be compelled by the force of the logic being presented to them even when they are uncomfortable with the logic's conclusions. The left hemisphere is slave to the logic of
"the system, regardless of experience: it stays within the system of signs. Truth, for it, is coherence, because for it there is no world beyond, no Other, nothing outside the mind, to correspond with." (The Master and His Emissary, Iain McGilchrist, 2009; page 193).
Truth, to the left hemisphere, is what is consistent with itself, internally. The criterion of truth is what is coherent within the confines of the system. Totalitarianism, which values consistency far above truth, is the ultimate triumph of the left hemisphere over the right, triumph all the way to the obliteration of the right.
Alternatively, when one's environment is peaceful and secure and the people are coming from their right hemispheres and are residing in their right hemispheres it is likely that what will sway their thinking is offering them the common sense facts of the matter. The criterion of truth will be how true the statement is to some reality out there, outside one's internal system of thought.
When the environment is threatening, however, the narrative will dominate the facts and counterintuitive convictions will often be made to become conventional wisdom.