A phobia specialist shares his 3 top tips to overcome any fear from spiders to public speaking

Phobias come in many forms: Some people fear spiders while others fear flying on a plane.

But the one thing they all have in common is that they're irrational, according to one phobia specialist.

"A phobia is an irrational response to a benign substance," Christopher Paul Jones, a London-based phobia specialist with a clinic on London's Harley Street, told CNBC Make It in an interview.

"As human beings, we are primitively hardwired that when we experience danger, our amygdala fires off, and then we do one of several things. Most commonly fight, flight, or freeze. So, either get angry and punch the thing, or we run from the thing, or we hide from the thing," he said. The amygdala is a part of the brain that processes emotions like fear or motivation.

This trigger is handy when we were fighting saber-toothed tigers or if we were in actual danger, Jones said. However, a phobia is when that response is to something that isn't dangerous.

Jones' clinic has treated a variety of phobias from a fear of water, heights, germs, needles, and even the fear of failure.

He explained that phobias develop through a conditioned response like that of Pavlov's dogs experiment. That famous experiment was carried out by Russian neurologist Ivan Pavlov who would ring a bell every time he fed his dogs. The dogs eventually started to salivate when they heard the bell ring because they associated it with food.

"Human beings do the same thing," Jones explained. "Most commonly with a phobia, at some point in your past, your brain has linked danger to something that has happened ... then whenever you think about that thing again in the future, it fires off that old response."

Jones' recently published book "Face Your Fears" guides readers through exercises