Human thought is mostly unconscious; and it is mostly metaphorical with a small amount of literalism. Cultural patterns can also be thought of as complex metaphors. Thus, to say that the brain influences culture it is through the creation of and perpetuation of metaphors. One good example of broad complex metaphors is the contrast in American culture between the Strict Father metaphor and the Co-parenting metaphor that is also generally associated with republicans and democrats, here. The strict father is an authoritarian orderly metaphor (left hemisphere) and the Co parenting metaphor is a right hemisphere one steeped in empathy. Also, note the simple understanding of the bible; the Old Testament is left hemisphere and the New Testament is right hemisphere, authority versus empathy.
Every culture is a complex whole comprised of hundreds, maybe thousands, of complex metaphors that lean one way or the other, hemisphere wise. One thing to remember is that complex metaphors can change over time, they can be made up of many sub complex metaphors that also change and maybe confound the issue by leaning the opposite way—the Strict Father pattern may have sub metaphors that lean right hemisphere because a touch of empathy is needed.
Awakenings are when a culture’s basic set of complex metaphors switch from one orientation to another, such as, in American history, from Romanticism to Modernism (from emphasizing the right hemisphere to the left one) during the Progressive Era, circa 1890-1920. During the Awakening metaphors satisfying both hemispheres are stressed, thus the era is exceptionally energetic and cultural entropy increases, here.
This basically sums up one important idea that drives this blog. The others are the Cultural seasons model, turnings, and the Generations model, both espoused by Strauss and Howe, here.