The neuroscience behind habit formation

Introduction: the power of habit and the brain

Did you know that almost 40% of our daily actions are not decisions but habits? This astounding statistic shows how much of our lives are on autopilot. According to neuroscientific research, this is not by accident but by design. Our brains, honed by evolution for efficiency, develop automatic routines to save energy for more complex cognitive tasks such as decision-making or processing emotions.

Understanding how habits are formed in the brain is more than fascinating; it is crucial. Whether you want to improve your health, increase your productivity or break a cycle of self-destructive behaviour, knowing the neurobiological mechanisms of habit formation can help you make lasting changes.

What is habit formation?

Habituation is a neurobiological process that converts conscious actions into automated behaviours, taking into account a variety of factors. Once a habit is formed, it can be performed with minimal conscious effort – like tying your shoes or checking your mobile phone.

At the centre of this process is a system of neurons working in synchrony, with the basal ganglia and nucleus accumbens, both structures in the brainstem, playing a key role that is the subject of intense research by scientists. The striatum, another brain region, plays a crucial role in habit learning, particularly in the formation of stimulus-response connections that automate behaviours and so influence neuronal activity.

This mechanism is supported by the reward system, in which dopamine, an important neurotransmitter, reinforces behaviours that bring pleasure or reduce discomfort.

Step 1: Intention and the prefrontal cortex

The habit cycle begins with attention and intention, which are controlled by the prefrontal cortex – the executive centre of the brain. This is where you evaluate your goals and decide, for example: ‘I want to start running every morning.’

This first action is purposeful and requires a great deal of cognitive energy and attention. The cortex evaluates stimuli, weighs up consequences and initiates behaviour. Brain researchers refer to this as a critical point at which motivation, planning and action are aligned.

🔬 Focus: Applied neuroscience emphasises that the initial intention is more likely to survive the strenuous early phases of habit formation the stronger it is and the more emotionally significant it is.

Step 2: Repetition and the basal ganglia

Once a behaviour is consciously practised, repetition begins to integrate it into the neural circuitry, causing the activation patterns of the cells involved to change. Each time you repeat the behaviour in response to a stimulus, a dopamine signal is sent out, strengthening the neural pathways in the striatum – a critical part of the basal ganglia, a group of brain areas involved in automated behaviour.

Over time, the behaviour becomes easier to initiate, smoother to execute, and less dependent on conscious thought.

🧠 Clinical Insights: fMRI brain scans showed that during early habit formation, the cerebral cortex is highly activated. However, as the behaviour becomes habitual, activation shifts towards the striatum, indicating a handover from conscious to unconscious processing.

Step 3: The Cue-Routine-Reward Loop and the Nucleus accumbens

Charles Duhigg's model of the cue-routine-reward loop is supported by neurobiology. When a stimulus (cue) arises – say, your alarm clock goes off – the habit loop is activated. Your routine (running) follows, and if you feel good afterwards, the nucleus accumbens marks this with a dopamine reward.

The mesolimbic system, an important dopamine signalling pathway, reinforces this behaviour by marking it as beneficial, which is associated with habit formation. This loop is not only psychological but also neuronal in nature and involves chemical changes at the synapse level.

💊 Interesting fact: substances like cocaine and alcohol hijack this very reward system and create a strong dependency through the same mechanisms associated with habit formation. Understanding these shared neural circuits is essential for both forming good habits and treating disorders such as addiction or alcoholism.

Step 4: Transition to unconscious competence

When repetition and reward continue over a long period of time, the brain enters a state called unconscious competence. The habit now runs automatically and frees up cognitive resources, illustrating the habit factor in everyday life. This shift represents a neural optimisation: fewer neurons are needed for execution, and the signal is transmitted faster and more efficiently.

This is the phase in which the basal ganglia shine and prefrontal involvement diminishes. The behaviour is now trained, reliable and effortless.

🧬 Muscle training for neurons: Research in the journal Neuron shows that the basal ganglia fire in tight loops when a habit is performed – almost like a muscle memory pattern, but with neuronal precision.

Step 5: Maintenance, adaptation and neuroplasticity

Once habits have been formed, they can be maintained indefinitely – but they can also be edited and changed. This plasticity is a hallmark of the nervous system. The cortex, particularly the prefrontal and orbitofrontal areas, can rewire when a habit becomes inappropriate or needs to evolve, affecting activity in these brain regions.

🧪 Hypothesis: A 2023 clinical study from dasGehirn.info suggests that changing habits requires ‘retraining’ the reward pathway, using targeted stimuli, new messenger substances and emotional cognition.

Just as drugs can create dependency by activating the reward system, targeted behavioural change can ‘re-code’ the circuit through targeted stimuli and positive reinforcement.

Beyond the habit loop: cosmos in the mind

Think of your brain as a cosmos in your head, a vast galaxy of interconnected neurons and nerve cells communicating via synapses. Habit formation is one of the many systems that arise from this dynamic neurobiological dance and are being explored in the spectrum of science. Every action, emotion or decision leaves a chemical trace that shapes you.

In science, learning habits is no longer seen as a fixed trait, but as a fluid and adaptive process – one that connects biology and behaviour, chemistry and cognition, neurotransmitters and motivation.

Conclusion: Use the mechanism correctly

The neurobiological foundations of habit show that the brain structurally adapts to recurring patterns. The key players are:

• Basal ganglia (automation)

• Nucleus accumbens (reward)

• Dopamine (reinforcement)

• Prefrontal cortex (initial learning)

• Striatum (stimulus-response association)

• Substantia nigra (motivation and movement)

• Synapses & Neurons (signal transmission and networks)

This interplay makes it possible for actions to become habits – and for us to consciously form new habits or purposefully change existing ones.

Habits are not created by magic, but by effort and the coordinated activation of brain structures such as the basal ganglia, the striatum and the nucleus accumbens under the direction of dopamine and the reward system.

The neuroscientific understanding of habits is not only important for brain researchers or psychologists, but for anyone who wants to achieve goals.

Q&A: The Power of Habit

What is the power of habit and how does it influence our lives?

The power of habit describes the brain's ability to anchor patterns of action so firmly through repeated behaviour that they run automatically, i.e. without conscious control. This automation is an evolutionary advantage: it saves cognitive energy because routine activities do not have to be decided anew each time. In neurobiological terms, this principle is made possible by the interaction of brain structures such as the basal ganglia, the nucleus accumbens, the striatum, the prefrontal cortex and the reward system. In particular, dopamine, a so-called neurotransmitter (chemical messenger), plays a central role here. It reinforces behaviours that have been experienced as positive – and thus promotes the formation of habits.

What happens in the brain when habits are formed?

Habit formation is based on a kind of neural loop that typically goes through three phases:

1. Cue: A sensory or emotional stimulus (e.g. the smell of coffee) activates a specific group of neurons.

2. Routine: This results in a specific action (e.g. going to the coffee machine).

3. Reward: If the action is associated with positive emotion, relief or enjoyment, the brain releases dopamine – mainly in the nucleus accumbens.

Repetition (repetition) stabilises this neuronal sequence. The nerve cells (neurons) involved form stronger connections via synapses, which leads to automated behaviour.

What role do the basal ganglia play in the process of habit formation?

The basal ganglia are a group of deep-lying brain nuclei in the cerebrum. They consist of:

• Striatum (divided into nucleus caudatus and putamen)

• Globus pallidus

• Substantia nigra

• Nucleus subthalamicus

Function: The basal ganglia are responsible for the automation of movements, initiation of action and motor learning. The striatum in particular is responsible for linking stimuli and reactions. As soon as a behaviour is repeated frequently, the basal ganglia take control – the prefrontal cortex (which controls consciously) is relieved. The action becomes a habit because it can be performed subconsciously, quickly and efficiently.

What is the striatum and what is its function?

The striatum is the largest part of the basal ganglia and consists of two main components:

• Nucleus caudatus: Responsible for cognitive and emotional aspects of habits.

• Putamen: Responsible for motor routines.

The striatum is the central processing station for incoming stimuli, especially those that occur regularly. It learns to react to certain stimuli (e.g. light, sounds, places, times) with specific actions – without conscious control.

What does the nucleus accumbens do?

The nucleus accumbens is part of the so-called mesolimbic system, which is responsible for processing rewards and controlling motivation. Dopamine is released here mainly during positive experiences or learning success. It acts as a kind of ‘reinforcement centre’: when an action is experienced as rewarding, the nucleus accumbens stores the experience and signals to the brain: ‘Do that again!’ This strengthens neuronal reward circuits – a crucial step in habit formation.

What is dopamine and how does it influence habit learning?

Dopamine is a neurotransmitter, a chemical released at synapses (junctions between neurons) to transmit signals.

In the context of habits, dopamine has several functions:

• Signalling reward and inducing feelings of pleasure or satisfaction.

• Promotes learning through reinforcement: Behaviour that triggers dopamine release is more likely to be repeated.

• Strengthens synaptic connections (synaptic plasticity), especially in the striatum and nucleus accumbens.

A dopamine signal is therefore activated when a behaviour is positively evaluated – and strengthens the corresponding neural circuitry.

What role does the prefrontal cortex play?

The prefrontal cortex is the anterior part of the frontal lobe in the cerebrum. It is responsible for:

• conscious thought

• planning

• decision-making

• self-control

In the early phase of habit formation, the prefrontal cortex is highly activated because new behaviours require conscious attention. As automation increases, its activity decreases because execution is taken over by the basal ganglia.

What is the substantia nigra?

The substantia nigra (‘black substance’) is part of the basal ganglia and is particularly known for dopamine production. It consists of two parts:

• Pars compacta: contains dopaminergic neurons.

• Pars reticulata: regulates movement sequences.

In degenerative diseases such as Parkinson's disease, the dopamine-producing cells of the substantia nigra die off – which leads to a loss of movement automatisation and shows how important this structure is for habit-based movement.

What does ‘neuronal plasticity’ mean?

Neural plasticity describes the brain's ability to change through experience. It concerns:

• Synaptic plasticity: changes in the strength of synapses.

• Structural plasticity: formation of new synapses or entire nerve cells.

• Functional plasticity: redistribution of tasks between brain regions.

This adaptability is the basis for changing habits, learning new routines or breaking old patterns.

What is the hippocampus – and how does it differ from the striatum?

The hippocampus is located in the medial temporal lobe of the brain and is responsible for:

• explicit memory (conscious memory)

• spatial perception

• learning new information

In contrast to the striatum, which is responsible for implicit, automatic habits, the hippocampus is responsible for conscious learning. There is a functional competition between these two systems: During the formation of habits, the hippocampus is increasingly relieved.

How do psychoactive substances affect the reward system?

Substances such as cocaine, nicotine or alcohol have a direct effect on the dopaminergic system – in particular on the nucleus accumbens. They lead to an excessive release of dopamine, which:

• Creates a strong sense of reward

• Triggers the neuronal reinforcement of unhealthy behaviours

• Promotes the development of dependence (substance use disorder)

This explains why addictive behaviour is neurologically very similar to habits – only at a pathological level.