The Formation of Habits in The Brain

The goal of this essay is to try and decipher how habits form in the brain, why they stick, and why we cannot shake bad habits even though we consciously know that they are detrimental. This is achieved by studying the formation of habits in rats and seeing what changes when we activate or deactivate certain areas of the brain.

Before we can delve into the formation of habits in the brain it is important to first know what a habit is an action that has become routine and no longer needs to be done deliberately. Habits are a double edge sword. Their advantage is that they allow us to automate menial tasks and free up brain power for more important things. On the flip side, when habits become ingrained, our brain no longer monitors what we are doing and it becomes hard to realize if a habit is becoming a detrimental addiction. On top of that, even if we do realize that we have formed a bad habit, it is extremely difficult to break it. According to Smith and Grabiel (2014), the stubbornness of habits can actually give us insight as to how they are formed. As it turns out the reason it is so hard to kick a bad habit, even though we know that it’s bad, is due to something called reinforcement contingencies. Reinforcement contingencies refer to the way that the brain decides whether or not to keep a certain habit. For example, if doing action A nets you a reward, and doing action b nets you a punishment, then the brain will look at both outcomes and use these to influence your future decisions.

Another method that the brain uses to determine future behaviour is called 'reward prediction error signals'. This is when the brain compares the real outcome of an action to the predicted outcome of an action to see how accurate it's prediction was. Based on this comparison, the brain then assigns a positive or negative value to the action making us either more or less likely to repeat it in the future. In order to get a closer look at how exactly the brain forms habits, Smith and Graybiel (2014) turned towards lab rats. In a variation of an experiment from the 1980, the researchers at MIT had rats run down a T shaped maze and either turn left or right at the top depending on an audio cue; at either end of the maze would be a reward in the form of food. The regular food was then switched out for distasteful food. If the rats, after tasting the now devalued reward, still ran to it, the researchers could come to the conclusion that the rat had formed a habit. The habit now goes, the researchers could study the brain of the rat to see what had changed.

In the first runs, before the habit had been formed, the motor control part of the rat's striatum was active the whole time the rat was running down the maze. After the rat had formed a habit, the researchers saw that the rat's neurons where mostly active during the begging and end of the run. What had happened was that the rat's striatal cells had turned the act of running down the maze into a single prepackaged action. Instead of the rat having to make continuous deliberate decisions to run down the maze, it could now do it 'without thinking'. As the researchers delved further into the functioning of the brain they found three major areas of the brain that had control over habits. The first was the striatum, which could package up the habits once they were formed. The second was the deliberation circuit which came into effect when deliberate action was needed while performing a habit. This circuit becomes used less as a habit becomes fully formed. The final part was the infralimbic cortex, which constantly monitors habits as we execute them. As it turns out, the infralimbic cortex needs to on and monitoring in order for us to be able to perform habits. This was confirmed by researchers who experimented on rats. When they turned off the infralimbic cortex, they were able to completely block even the most ingrained habit.

In conclusion, when habits are formed, they are converted into chunks of neural activity and can be performed almost in a subconscious manner. However, researchers found that even when we seem to be performing habits without realizing it, our infralimbic cortex is always monitoring our actions. This realization makes Smith And Graybiel (2014) hopeful that future technology may someday allow us to control our habits via the infralimbic cortex. For the time being however, we can take solace in the fact that we are still in control of our habits, even though it may not always seem that way. As a final message, the researchers leave us with a quote from Mark Twain reminding us that getting rid of habits is a process to be taken slowly.