Your eyes have developed to be a targeting tool like a rifle sight. We are haptic animals, we see and we grab things, we go towards something and are the best at predicting the movement of medium sized objects in a regular space at regular human speeds. We are predators, our bodies were made for throwing objects and following a moving target or the light. The brain does the same thing when it tries to represent reality to you the best it can. You never have access to the (full) reality, you have acess to the current representation – a collage of emotion, expectations, previous experiences and sensory input and the brain chooses a target, a goal (because your subconscious mind already knows that there is no coherent life construct without a goal, whatever it may be for you in particular),
We’re obsessed with hitting the center of the target. So you’ll transform the world into a “target” and compare the consequences of your actions to how close it came to the bullseye. If it is a match the behavior is rewarded by feel good chemicals (and bad loops can be reinforced just as readily as good ones) – for example if you have trouble sleeping you can find that eating sugary things all day gives you bursts of energy and the target is reached (although through a bad pathway and the more you do it the harder it is to stop), or you’ll study and put in some effort and pass an important exam, be rewarded by the brain by lowering cortisol and a shot of dopamine and conclude that effort hits the target and continue on doing it.
Hippocampus serves as a melting pot that takes the model of the world you’ve made, cross checks it with the sensory input (which is the closest to reality you can get) and decides whether it’s a match. If it is a match, you still feel homeostatic balance and continue on, but upon stumbling on a mismatch the subcortical emotionality gets switched on, like an autopilot suddenly stopped working and the older darker part of the brain takes the wheel with fear, anxiety, hesitation, doubt and freezes you to give you time to reassess and keep you alive. The subcortical emotions are never really off, they are just supressed, so they don’t need a lot of reboot time and can react as fast as possible when they see a mismatch which is equated with danger. These primal emotions don’t really care if it’s a job interview or being chased by a wild beast, the reaction is the same.
Your brain is comparing the most desired reality (not the objective reality) to the feedback it gets that – the model of the world you think is happening (still not objective). This is why being lied to or betrayed hurts so much. It’s not just the superficial level of having to adapt your behavior towards someone but it goes far deeper – if you miss the target (what you thought was the truth before you realized you were lied to) you don’t only realign and adapt your aim but start to rearrange your personality and whole perception and view of the world, because if this didn’t work what else might you be wrong about? Is this failure representative of a fundamental character flaw that needs to be eradicated? So, missing the target doesn’t only make you feel annoyed because you wasted a perfectly good arrow, but you start rethinking the whole design of the bow that made it not work. Betrayal is therefore not just a single act but an insult to your reality, and the same mechanisms that help us make sense of the world are the ones that can potentialy do most damage and cause the largest tectonic shifts.