Fear is not just an emotional response — it's a business. And, right now, business is booming.

Clever entrepreneurs have learned how to capitalize on a bizarre trait that some of us possess — getting a kick out of being scared spitless.

An estimated 157 million Americans plan to celebrate Halloween this year and spend $6.9 billion on everything from candy and costumes to the spookiest scream-fest they can find.

Those of us who are seeking screams this Halloween have a rare kind of personality that Frank Farley, who is a psychologist at Temple University, calls "type T" or "Big T" (thrill-seeking) personality.

"The 'Big T' personality anchors one end of a continuum; at the other end is the opposite 'Little t' personality, who avoids risks and unfamiliar places and people," author William C. Cockerham explained in his book "Society of Risk-Takers: Living Life on the Edge."

Farley found that those with “Big T” personalities also tend to be more creative, extroverted, and risk-oriented, than most others.

Since most of us fall somewhere between the two ends of this continuum, Farley thinks “Big T” and “Little t” personalities are relatively rare.

Why some of us seek screams

According to studies, only about 10% of the population classify as “Big T”, Margarita Tartakovsky reported for PsychCentral.com.

However, why these 10% revel in fear is not necessarily the same.

Some seek the adrenaline rush while others tolerate the thrills and chills for the aftermath — the satisfaction that results from overcoming a threat or obstacle.

Interestingly, Farley discovered that most “Big T” personalities fall under a specific demographic: males between 16 and 24 years old.

It could be that many males of this age have low levels of the feel-good hormone dopamine and, therefore, must go to extremes to release enough to feel any type of stimulation, according to a theory proposed by psychologist Marvin Zuckerman at the University of Delaware.

What personality type are you?

Zuckerman’s research has found that extreme thrill-seekers tend have a number of traits in common: They are typically impulsive, highly social, and uninhibited, Cockerham wrote in his book.

Moreover, these personality types often seek out people similar to themselves. Therefore, their friends and spouses will likely have the need for fear, as well.

Sometimes, the need for extremes is so high, that "Big T" personalities will turn to crime because it's the only thing that gives them enough of a rush.

Christian Bales' character in the film "American Psycho" is a perfect example of someone who performs severely criminal acts for entertainment because without them he's bored out of his mind.

So do you think you’re one of the 10%?

You can find out for yourself. Zuckerman created the "Sensation Seek Scale," which is a quiz that he uses to study different personality types.

You can take the test yourself here.