MDCHo - On Good Habits Series

On Good Habits – The Science of Habits

This is Part 2 of our series On Good Habits.  In Part 1 of the Series, you learned what habits are and why habits are so important to your success and personal growth.  This Part focuses on the science of habits: what happens in our brains when “learning” a new habit, and the “simple” neurological loop that governs all habits. [1]

Overview of the Science Behind How All Habits Work [2]

When willpower runs out, we generally rely on our habits – good or bad.  And since we only have so much willpower, we should know how habits are formed in the brain, so we figure out how to fall back on the right habits. The root of all habits lies in the basal ganglia of the brain.  The basal ganglia is a group of subcortical nuclei situated at the cerebrum, and is comprised of limbic, two associative, an oculomotor, and a motor pathway.  The basal ganglia are associated with motor functions, procedural learning, and – the topic of today’s discussion – habits and routine behaviors.

Importantly, when a new habit is being learned, the associative basal ganglia and prefrontal cortex, which supports working memory, are engaged. As the routine is repeated in the same context over and over again, the information is slowly reorganized by the brain – a process called, “chunking” whereby the brain converts a sequence of actions into an automatic routine.  While this information is ordinarily organized in terms goal or outcome, it shifts to the sensory motor loop which supports the Habit Loop association in your brain.  One effect of the reorganization is that our brain no longer retains information on the goal or outcome, which explains a lot:  while a habit may initially have been formed to meet some goal aside from attaining the reward, that goal-orientation is lost to the cue-response association.   This is an evolutionary response which allows your brain to reserve the cerebral cortex for what it deems more important functions.

The Neurological Loop Governing All Habits

As we discussed in Part 1 of On Good Habits, habits are formed in part because the brain is constantly looking for ways to save energy.  Without habits, our brains would literally be overwhelmed by decisions each day.  To combat fatigue, our brains have developed a neurological system called, the Habit Loop, which governs all of our habits.  The Habit Loop has three elements: (1) Cue, (2) Routine, and (3) Reward. [3]

MDHCo - Habit Loop

The Habit Loop has three parts: Cue, Routine, and Reward.


The Cue (sometimes called, the Reminder) is the trigger which tells your brain to shut down and start a particular habit.  Remember that when endocannabinoids are released in the brain during a routine, the prefrontal cortex – responsible for, among other things, your decision-making ability – is basically turned off.  The cue is the trigger for this chemical’s release.  For the mice in the MIT experiment discussed in the last Section, the cue was a clicking sound telling the mouse to start the maze.   A cue can be a (1) time of day; (2) a location or environment; (3) a temporally preceding event; (4) an emotional state, or (5) the company of a specific person or people. [4]

The Routine is the activity or series of activities that you perform after being triggered by the cue.  A routine can be a physical, mental, or emotional response.  In the MIT experiment, after the mouse heard the clicking sound, it began to run the maze.  But a routine could equally be answering the phone when it rings, brushing your teeth before bed, or lighting a cigarette each time you get in the car.

The Reward is how our brains determine whether or not a particular loop is worth remembering.  As our brain is always looking for shortcuts, the reward helps the brain determine the value of the particular behavior and whether to employ the particular behavior loop again.  A reward can be that something interests you or excites you; it can satisfy curiosity or it can entertain you; it can really be anything your brain finds valuable to have more of.  For the mice in the MIT Experiment, chocolate was the reward.  For the teeth brusher, it’s the tingling feeling you get “so you know it’s working.”

With each successive encounter of the cue, routine, and reward, this loop becomes increasingly more subliminal.

The Habit Loop IRL

Here’s a real-life example of what The Habit Loop looks like:  every day around 3pm I walk down to the cafeteria and get a soda and a bag of chips.  In that case, the cue is the time of day – about 3pm; the routine is walking down to the cafeteria; and the reward is the signals my stomach sends my brain while eating the chips and drinking the soda.

Another example could be receiving a notification from your Outlook.  The notification pops up on your monitor (cue), so you click the alert box at the bottom of the screen and begin reading message (routine) and then you learn who is emailing you or what appointment is next on your agenda (reward, the satisfaction of curiosity).

Cravings: What Makes Habits Stick

While many people are aware of the Habit Loop, far less realize that there is an important fourth force at work: neurological cravings.  Cravings are the result of the interaction between the cue and the reward.   Essentially, as the cue and reward connection grows stronger and more intertwined, your brain begins to associate one with the other so that a sense of anticipation for the reward arises on cue.[5]  That anticipation is called a craving, and they are what make cues and rewards work.  Cravings are essentially what powers the Loop and cements a series of actions as a habit’s cue becomes more closely linked to its reward.

Due to this neurological loop, habits essentially become hardcoded into our brains, making them sticky (for better or for worse).    And for that reason, habits never really die.  Notwithstanding that, there are powerful ways in which you can change a habit so that it can work to your advantage.

What’s more, habits — along with memory and reason — have been shown to have the most profound effect on a person’s behavior. While we may not remember exactly how a habit came to be, once something is made habitual, once it becomes deep-rooted in our mind the habit influences all aspects of our life – often without us even knowing it.

In Part 3 of our series On Good Habits, you’ll learn more about cravings role in creating new habits as well as how to hack The Habit Loop to change any habit you desire.


  1. Preparation for Habit-Tracking Exercise: Over the next day, pay attention to everything you do. Write down all the habits you can spot — good and bad.  You may be surprised at the results.  And if you’re having trouble figuring it out, ask someone for help.  Often others are able to spot these more easily than you are.
  2. Compare the list of habits from the previous homework assignment to the above list.  Were there habits you didn’t know you have?  Are there any habits that you thought you had, but you actually don’t?


[1] The biological process actually quite complex, but the system can be broken down in layman’s terms for easy explanation.

[2] How We Form Habits, Change Existing Ones on Science Daily.

[3] Charles Duhigg, The Power of Habit 2010. Also called, The Three R’s of Habit Change (Reminder, Routine, and Reward).

[4] Charles Duhigg, How Habits Work.

[5] Charles Duhigg, How Companies Learn Your Secrets, New York Times Feb. 16, 2012.

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