A lot of factors go into our decisions to purchase a car: affordability, reliability, availability and several others are likely among the top few for many consumers. But there's no denying that our cars are also a statement about our personality. A sensible four-door sedan sends a different message than a minivan, and a sexy little sports car sends a different message than an SUV.

But that sports car and SUV have more in common than meets the eye: Both of them appeal to the reptilian part of our brains. While we don't have actual lizards living in our heads, the reptilian brain is the deepest part of our brain, or the "gut level." And according to Dr. G. Clotaire Rapaille, the founder of Archetype Discoveries Worldwide (a firm that studies how shoppers choose new cars),  this part of our brain controls survival functions, including hunger, breathing, and fight-or-flight responses. The reptilian brain likes "power, big, sex, survival, and reproduction." [source: Carwinism.com]

Rapaille says we have three basic levels to our brain:

  • Reptilian: the part of our brain that likes power and sex
  • Limbic: the emotional part of our brain
  • Cortex: the highest-functioning, number-crunching part of our brain

What do these three levels have to do with car manufacturing? By appealing to that gut level of our brains, which functions without much input from the emotional or rational parts of our brains, automakers can get us to buy bigger, faster, cooler -- and yes, more expensive -- vehicles.

In the case of SUVs, for example, our reptilian brains like the fact that the driver sits higher, enabling him or her to see farther and giving a feeling of safety. It's only a feeling, though -- our rational brains know that higher vehicles have a greater tendency to roll over than lower ones.

Keep reading to find out how manufacturers were able to make the reptilian brain override the cortex and make SUVs wildly popular in the 1990s and early 2000s.