Imagined vs. Real Experiences
The brain cannot distinguish between a real experience and an imagined experience. As long as the imagined experience creates an emotion in your brain, it will pave a neural pathway. Emotions are certain mixes of neurotransmitters, and neurotransmitters make neural pathways from the neurons firing at that moment.
Imagining Negative Situations
Say for example that you repeatedly imagine someone walking towards you on the street and this stranger jumps you with a knife. If it is vividly imagined, your body will start pumping cortisol and adrenaline. These will together pave a neural pathway that link strangers walking towards you with danger and the possibility of death. Your body will pump cortisol when you get in a similar situation, so that you scan for danger and the adrenaline will come pumping as the stranger comes near you.
A Negative Feedback Loop
Not only is cortisol together with adrenaline a very uncomfortable feeling and unhealthy long-term, but when cortisol is present you’re scanning for danger and the stranger will seem more threatening to you. Innocuous movements might seem like a challenge, and you yourself will take on a much less sympathetic demeanor. This again will make the stranger trust you less and maybe get some cortisol and adrenaline for himself. You can probably see the start of a negative and dangerous feedback loop.
Imagining Positive Situations
The same process can be done for positive feelings. You see the same stranger in your imagination but this time he smiles at you and says hi in a jovial tone, you say hi back, smile, and you stop to chat about the football game, you exchange names and shake hands. Your body will now pump oxytocin. You get the warm fuzzy feeling of trust and a neural pathway gets paved.
A Positive Feedback Loop
Now when you meet the stranger, your oxytocin starts flowing, a smile comes to your face and you have an open inviting demeanor. The stranger sees this and his body relaxes. The chance of a smile or at least a jovial “hi” skyrockets.
An important point about these neural pathways is that they are built by repetition (slow process) or strong emotions (fast process). The response you have in any given situation will depend on which neural pathway is the broadest, because electricity flows on the path of least resistance.
The impulses you get are controlled by the limbic system, of which you have no control whatsoever. But, and this is a big but, you can override the impulse. You can decide not to act on it, thanks to your cortex – conscious thought. This is where we get our free will. Every time you say no to an impulse, meaning that you do not act on it, you open up the possibility of creating a new neural pathway, or habit if you will.