The American Society for Addiction Medicine explains:
We all have the brain reward circuitry that makes food and sex rewarding. In fact, this is a survival mechanism. In a healthy brain, these rewards have feedback mechanisms for satiety or ‘enough.’ In someone with addiction, the circuitry becomes dysfunctional such that the message to the individual becomes ‘more’, which leads to the pathological pursuit of rewards and/or relief through the use of substances and behaviors.
In simpler terms, addiction involves changes in the brain that cause the following (and more):
- addict craves the behavior / substance
- and has reduced ability to say “no” to it
- yet at the same time it fails to satisfy like it used to, leading to seeking more and more and getting less and less satisfaction in return
- dysfunctional stress response that causes intensified cravings under even mild stress — e.g. “I gotta have that smoke!”
Why does it happen? It’s like having “two brains” (really two brain systems):
- The “feeling brain” (limbic system) is responsible for the drives / instincts that keep you alive. The “reward” circuitry is part of this system.
- The “thinking brain” (prefrontal cortex) helps you solve problems, make plans, exercise self-control, and make smart choices between right and wrong.
- It’s important to have your thinking brain in charge because the feeling brain literally cannot think before acting. If the passions are in control, then they will choose what feels good right now, without considering consequences or what is really best.
- Further, the more the “feeling brain” is used, the stronger it gets (because of rewiring), at the expense of the “thinking brain.” OTOH, using the thinking brain strengthens it instead.
Supernormal stimulus:
- Animal studies done by Niko Tinbergen and others show that instincts leading animals to respond to certain stimuli can be hijacked by “supernormal stimuli.”
- What does this mean? Basically, he created artificial stimuli that were stronger than the stimuli for which responses had evolved naturally.
- He found that (e.g.) birds would sit on large, brightly-colored and patterned FAKE eggs in preference to their own real eggs, feed FAKE chicks with wide mouths painted bright red in preference to their own real chicks, etc. The animals behaved in ways that were a detriment to their own survival because they couldn’t say no to the fake stimulus!
Modern society also offers us supernormal stimuli, e.g. junk food, TV, video games, porn, internet.
Human beings have similar instincts, but one BIG advantage: rational minds that enable us to bypass the FAKES and choose the REAL.