The permanence of habits

As you have seen, after multiple repetitions of a certain reward-tied behaviour, a given routine will become tied to a cue and then simply acted out without conscious thought even if it doesn’t necessarily match our values or desires. It is easy to dismiss this data because, of course, we aren’t rats, but it’s important to remember that these processes are highly evolutionarily conserved and therefore play in to the governance of our behaviours, too.

This is why people will often drive on their usual work commute when they had intended to go somewhere else, if they set off at the same time of day as they usually would. Habits aren’t just powerful, though, they are considered semi-permanent because they are hardwired into your brain.

Continuing with the rat experiment from above, it was noticed that during the initial programming of a habit, the infralimbic cortex had very little activity but as the goal-seeking striatum activity became less and less, the activity in this other structure increased, indicating that it was involved with ‘housing’ habit circuitry. A technique called optogenetics which involves shining a light into the brain to disrupt certain patterns was used to ‘turn off’ this area.

After this was done, the rat started to avoid the chocolate milk and, over time, re-trained itself to turn towards sugar water regardless of the sound. The habit was lost and therefore the rat’s behaviour became goal-oriented once more and it was displayed that chocolate milk was no longer seen as valuable.

In the final stage of the experiment this process was undone, however, and the rat went immediately back to its old habits. It ran to the nausea-associated chocolate milk even though it had established this was a bad idea. The habit was somewhat permanently engrained.

This is important for one simple reason – you cannot remove the physical systems within your brain that govern a given habit. Once you have a well-engrained habit it stays for life. This is why a smoker who, after 72 hours no longer has physical cravings to smoke, will pick smoking back up after 10 years of cessation simply after having 1 cigarette.

So, to summarise the above:

• Habits are series of actions bracketed into a given routine
• They are acted upon after experiencing an associated cue, in order to get an expected reward
• Initially the reward is something tied to your values. It’s a goal towards which you ‘want’ to progress, and is approached as an exploratory behaviour, reinforced by dopamine
• Over time the areas of your brain involved with value based judgements become less and less active as the areas involved with habitual action become more and more active
• Eventually the area of the brain associated with habits (the infralimbic cortex) will communicate to your striatum and then your sensorimotor cortex to act upon a certain cue, even if it goes against your values
•  If the infralimbic cortex is ‘turned off’ in a rat, behaviour returns to being goal oriented but once it’s turned back on, the habit returns even though the rat has established a ‘better’ course of action, indicating that the circuits that operate habitual behaviour are at least somewhat permanent
• Similar behaviours are observable in humans

However, we have one advantage that lower animals do not. We exist with a higher level of consciousness than anything else on the planet, with an understanding of the future and an appreciation for vague and somewhat abstract consequences. Unlike rats, we are not our brains and we are able to engage executive function if only we are willing to make the effort to do so.