This article looks at some mass social changes and their timeline of acceptance (based on state laws then federal laws/rulings), including women's suffrage, abortion, prohibition, interracial marriage, and now same-sex marriage and marijuana legalization.
This Is How Fast America Changes Its Mind
As the Supreme Court considers extending same-sex marriage rights to all Americans, we look at the patterns of social change that have tranformed the nation.
I imagine it correlates pretty closely to how fast old people die. It's not people changing their minds, it the country's minds literally changing.
+Al Hunt That's certainly one of the factors involved. Others include someone else going first to set a precedent, and becoming familiar with the change involved and thus not as fearful of it as change qua change.