“Reptile theory” is a litigation tactic used by plaintiffs’ lawyers to appeal to a jury’s survival instincts by casting defendants as threats to community safety. Popularized by Don C. Keenan and David Ball in their book, Reptile: The 2009 Manual of the Plaintiff’s Revolution, it builds on the “triune brain” neuroscience theory, which posits that the human brain is made up of three regions of increasing evolutionary complexity.