Even though our brain weighs only just 2% of our body weight but it consumes about 20% of total energy of our body. So, in order to work efficiently and make best use of the energy, our brain forms habit, so that you don’t have to think and make decision each time while doing things you regularly do like brushing teeth, eating food, walking, talking etc. And your mind is freed to think about other important things like planning for project, thinking about what to do tonight, how to accomplish that project etc.
Habit works on three steps, Cue or Trigger, Routine and Reward. For example some people have habit of brushing teeth right after each meal. Here finishing meal is a Trigger, brushing the teeth is a Routine and feeling fresh or feeling clean teeth is a Reward. When they face the Trigger (i.e. finishing meal), they don’t think whether to brush teeth or not, how much toothpaste to put or which hand to use, they just do it automatically without giving any thoughts. While walking, have you ever thought which leg to move first, whether left or right, certainly not? You do it automatically, but when you try to switch your leg you feel odd. And each time you achieve Reward after following your Routine, the brain is signaled that this habit is worth storing and hence habit gets stored and enforced each time you repeat.
In the same way, stress, feeling low, nervousness, certain people or place can be trigger for your addictive habit. So when these triggers occur, you will feel strong urge to perform your habit. Once you perform your addictive habit (Routine) you will receive Reward in the form of pleasure or high. This gives signal to the brain to enforce it with more efficiency each time when the same trigger is observed. Hence, habit forms and becomes more stronger and more automatic each time you repeat it.
So, for a smoker, other people smoking around him can be a trigger. Entering a certain shops or attending the social occasion can be a trigger for an alcoholic where he feels strong urge to drink alcohol. Beside this stress, nervousness, anxiety etc can be trigger for an addict, which may ignite strong desire or craving to engage in addicting behavior.
Not only this, as addictive behavior releases more amount of dopamine, bad habits like addiction are easily formed compared to good habits like exercising, brushing teeth, meditating etc. Because dopamine narrows our attention and helps to concentrate on doing the things that is releasing it. That’s why you don’t think about other things while you are truly enjoying something like watching movie, playing sports, listening story or eating chocolate, and you remember these moments in a very precise way. On the other hand, those activities which don’t release dopamine becomes boring and our mind wanders to engage in or think about other tasks which releases more dopamine, which causes distraction. That’s why our mind gets distracted while studying boring material and it’s hard to remember what we just studied.
One interesting fact is, if you love smoking cigarette rather than drinking alcohol or chewing tobacco, then you are not alone. When you consume addictive substance orally, then you will get slow effect. As it has to reach stomach, dissolve and mix with blood then enter the brain. But on the other hand, if it is smoked or injected intravenously it will directly mix with blood and reach the brain in short time, giving instant high. Since it gives rapid and large high, hence drugs that are taken intravenously or smoked are far more addictive than drugs that is taken orally. It’s like choosing the company that deliver goods within hours rather than company that says “OK, Come back week later.” You might have also noticed, that fast internet is more appealing than slow one as it quickly gives desired result. Same goes for drugs, the one that gives instant high is more appealing than the other. And that’s the reason, people easily get addicted to smoking cigarette, it’s easily available and gives instant high.