Are we slaves to our lizard brain?

I recently finished the book Charity & Sylvia. Amazon recommended it to me after I finished Gentleman Jack: The Real Ann Lister (Movie Tie-In). While I think Gentleman Jack is more entertaining to read, I can definitely recommend Charity & Sylvia, especially if you are interested in the history of female husbands in 18th and 19th century US.

But what does this have to do with lizard brains?