Navy SEAL brains are trained to alter how they process fear

Imagine how long it takes to reprogram millions of years of evolution in the human brain, trying to snuff out the instincts that kept early humans alive. Forcibly changing those instincts to instead train an individual to put themselves in harm's way. If you ask a Navy SEAL, he'll tell it takes about about six months, give or take — the amount of time you need to get through BUD/S.

If it ever seemed like SEALs and SEAL veterans just tend to think differently than most other civilians and veterans, then you're on to something. Their brains have actually been reprogrammed, specifically within the amygdala, to process fear differently from everyone else.

Fear is a primal instinct that kept a lot of early humans from becoming food for dire wolves and cave hyenas. These days, humans have fewer cave hyenas to worry about, but that instinct still keeps us from walking down a dark alley in a tough neighborhood at night. Fear helps us manage risk and book it out of a situation that overwhelms us. The part of the brain that processes fear is the amygdala, which actually processes all emotions.

With fear present, the amygdala alerts the brain stem, which causes you to sweat, causes your heart to race, and initiates your body's "fight or flight" response. The amygdala's emotional response process is twice as fast as the frontal lobe's logical decision-making processes.

Humans, as it turns out, are emotional creatures. The Navy takes full advantage of that.

"We introduce our students, on day one, to absolute chaos," Capt. Roger Herbert, then-commander of the SEAL training program at Coronado Island, told the History Channel. "When you look at historic mistakes on the battlefield, they're almost always associated with fear and panic. So, the capacity to control these impulses is extremely important."

Petty Officer 1st Class Zack Schaffer, U.S. Navy SEAL and an advanced training instructor, engages targets during a close quarters defense hooded-box drill at Naval Special Warfare Advanced Training Command. The drill tests operators' ability to quickly react to lethal and non-lethal threats with the appropriate use of force. Individual augmentees are used as role players during each scenario.

(U.S. Navy Photo by Petty Officer 2nd Class Michelle Kapica)

Navy SEAL recruits are put through special training to change how their brains react to fear. The Navy wanted to know why lifelong athletes could fail BUD/S training while some kids who never saw the ocean before the Navy could succeed.

One close-quarters combat exercise, the hooded box drill, involves putting a hood on a SEAL candidate that renders them blind and deaf, and then putting them in a combat situation. The hood is then ripped off and the candidate has to respond in seconds.

Sometimes, the response needs to be lethal and sometimes it needs to be nonviolent. Panic is not an option. Constant exposure to fear results in experiencing suppressed emotional responses and less lag time between the fear response and the frontal lobe logic process.

A gap between the two responses could leave a special operator standing frozen, unable to respond, not knowing what to do next. Navy SEALs do not have this problem.