Whether you’re aiming to quit smoking or build a healthier lifestyle, changing a habit involves more than just self-control. According to recent research, habits are formed through a combination of reward-based learning and repetition. The brain develops these patterns over time, making behaviors feel automatic.

At first, forming a habit requires conscious effort. Consider learning to drive: you have to think about mirrors, speed, and signals. But as your neural pathways strengthen with practice, those actions become second nature. Eventually, the decision-making parts of your brain become less involved.

On average, building a habit can take around 70 days, though this varies. What accelerates the process is dopamine, a « reward chemical » that gets released when we experience something positive. This creates motivation to repeat the behavior. Even when the instant gratification disappears, repetition alone can maintain the routine.

Habits as Mental Shortcuts

Roughly 45% of daily behaviors are driven by habits. You may not think about putting on your seatbelt, or the route you take to work — it’s all embedded in your brain. Over time, habitual actions even shape your preferences. If you drink coffee every morning, your brain learns to favor it, not because it’s better than tea, but because it’s part of your routine.

As Dr. Marcus Stephenson-Jones from University College London explains: once a pattern is established, the brain can bypass value-based decisions and rely on what’s familiar. In other words, habits reduce cognitive load, letting your brain save energy.

Two Systems Behind Habit Formation

A team of Swedish researchers recently found that habit formation is guided by two parallel systems:

1. A reward system, triggered by dopamine in the brain’s decision centers.
2. A repetition system, which gradually makes behaviors feel automatic.
   

This dual-system model explains why we continue certain behaviors even after the initial reward fades — the action itself becomes linked to a familiar, internal feedback loop.

Mice and the Science of Habit

To dig deeper, researchers trained mice to complete a task: press buttons based on sound cues. Each correct response led to a small reward — a sip of water. Over time, the mice became quicker and more accurate, their movements almost automatic.

This learning process was tied to a spike in dopamine within a brain region called the striatum, known for its role in motor control and learning. When scientists disrupted dopamine signals in this area, the mice struggled to learn the task, confirming the striatum’s role in habit formation.

Even after the external reward lost its novelty, familiar movements still triggered dopamine release, helping explain why routines like working out or brushing teeth stick with time.

Implications for Parkinson’s Disease

This research may also shed light on Parkinson’s disease, where dopamine-producing cells deteriorate. This disrupts movement and may impair the brain’s ability to form and execute automatic behaviors. Targeting the habit-forming system could open new treatment possibilities.

Final Thoughts

From small morning rituals to major lifestyle changes, habits dominate our behavior more than we realize. Instead of trying to « break » bad habits, consider replacing them with more helpful ones. If stress makes you crave snacks, try walking instead. Movement, paired with repetition, rewires the brain — and may be the most effective path to lasting change.