Here's how phobias work.
There are two parts to your mind – one that thinks, and one that feels.
The thinking part is the conscious, rational mind that you are using now as you read this.
The feeling part is the unconscious, emotional mind. It takes care of automatic tasks like regulating the heart, controlling pain and managing our instincts.
It's the unconscious mind that is programmed to act instinctively in times of danger. It reacts very fast – making you run or fight – rather than allowing your thinking mind to philosophize while you are attacked by a tiger. This has great survival value.
The unconscious mind is also a very fast learner. The same emergency route that can bypass the rational mind in times of danger can also stamp strong emotional experiences (traumatic ones) in the unconscious mind. This makes evolutionary sense – it ensures that we have vivid imprints of the things that threaten us.
And just as we have two minds, so we have two memory systems: one for the facts and one for the emotions that may or may not go with those facts.
Sometimes, when a person experiences a very traumatic event, the highly emotional memory of the event becomes trapped – locked in the emotional brain – in an area called the amygdala which is the emotional storehouse. There is no chance for the rational mind to process it and save it as an ordinary, non-threatening memory in actual storage (in the hippocampus). Like the memory of what you did last weekend.
Instead, the emotional brain holds onto this unprocessed reaction pattern because it thinks it needs it for survival. And it will trigger it whenever you encounter a situation or object that is anything like the original trauma. It does not have to be a precise match.
This is pure survival again. You only need to see part of a tiger through the bushses for the fear reaction to kick in again – for the "fight or flight" response to trigger – you do not have to wait until you see the whole tiger or identify it exactly as the tiger that attacked you before. In fact, it probably only has to be something orange and black moving through the bushes. This is why the pattern matching process is necessary approximate, or sloppy. You err on the side of safety. You do not have to have all the details to know if something is dangerous.
This is the basis of a phobia: a fear response attached to something that was present in the original trauma. The response is terror, shaking, sweating, heart pounding etc. And because of the sloppy pattern-matching it can get stuck to literally anything – animal, mineral or vegetable. It may not even be glued to the thing that caused the trauma. So a child attacked in a pram by a dog may develop a phobia of prams rather than dogs.
It is because phobias are created in this …