Why do we do what we do? The answer: the “reptile brain.” Cognitive research and evolutionary biology tell us a lot about human motivation, and, unlike some card trick at a cocktail party, the information is useful now.

How our brains developed thousands of years ago illuminates the whys of our actions today. Here’s an example. I am able to tap this column out because my ancestors survived the plains of the Serengeti when a lion was about to devour them. They survived based on the power of contrast: green bush, green bush, brown lion, green bush. Run. We still scan the horizon to look for contrast. I try suits, including retaliation cases. The most effective plaintiffs lawyers use contrast: “My client was a good employee until she complained about discrimination, and then everything changed and she was fired.”