Chapter 3: Reward, Dopamine and Why Some Habits Stick

Just One More Look

Florin is twenty-nine and works as a graphic designer for a company that makes signs and posters. He enjoys his work, but he has a habit that he finds increasingly frustrating. Every few minutes, he picks up his phone and checks a social media app. He scrolls for a minute or two, sees a few posts, perhaps a message or a notification, and puts the phone down. A few minutes later, he picks it up again.

Florin has tried to stop. He has deleted the app, reinstalled it a week later, turned off notifications, turned them back on, promised himself to check only at lunchtime and broken the promise by mid-morning. What puzzles him most is that he does not even enjoy the checking very much. Most of the time, there is nothing interesting. He scrolls past posts he does not care about and feels slightly empty afterwards. Yet the urge to look again is strong and constant.

One evening, Florin counted how many times he had picked up his phone that day. He made a mark on a piece of paper each time. By bedtime, the paper was covered with marks. He was shocked. He felt as if something inside him was pulling the strings, and he did not understand what it was or why it was so powerful when the reward seemed so small.

Florin's experience is very common, and it touches one of the most important parts of how habits work: reward. Habits are built and strengthened by the rewards that follow them. But the way the brain learns from rewards is surprising, and it explains why some habits, like Florin's phone checking, can become so sticky even when the rewards seem small or even disappointing.

This chapter looks at what brain science says about rewards, and especially about a chemical messenger called dopamine, which is often misunderstood. Understanding it can help explain why some habits are so hard to break, and how to build new habits that last.

How Rewards Build Habits

A habit, as we have seen, is a learned link between a cue and a response. But what makes the link form in the first place? Much of the answer lies in what happens after the response. When a behaviour is followed by something good, a reward, the brain learns to repeat that behaviour in that situation. The reward strengthens the link between cue and response. This basic principle has been studied for more than a century and is one of the best-established ideas in psychology.

Rewards can be many things. Some are obvious: food, money, praise, pleasure. Others are subtle: relief from boredom, a sense of completion, a feeling of connection, a small piece of new information, a moment of calm. For Matilde in Chapter 2, the reward of the three o'clock biscuits was partly the taste, but mostly the break and the small lift in energy. For Florin, the reward of checking his phone is less obvious, but it is there, as we will see.

Timing matters. Rewards that come immediately after a behaviour are much more powerful in building habits than rewards that come later. The brain is very good at linking actions with their immediate results, and much less good at linking them with results that come days, months or years later. This is one reason why many unhelpful habits are easy to form and many helpful habits are hard. Eating a biscuit brings an immediate reward. Eating a healthy meal brings benefits that come slowly, over months, and are hard to feel at the moment of eating.

Scientists and economists have studied this preference for immediate rewards in many ways. People, and animals, tend to value a reward less the further away it is in time. A small reward now often feels more attractive than a larger reward later, even when the larger reward would be better. This tendency is well documented and helps explain why it is often hard to choose behaviours whose benefits lie in the future.

There is one more important point about rewards, which we met in Chapter 1. Once a habit is strongly established, it may continue even when the reward is no longer very rewarding. The rats kept pressing the lever after the food was no longer wanted. The cinema popcorn eaters ate stale popcorn. This is because, with repetition, the habit becomes linked more to the cue than to the reward. The reward helped build the habit, but the habit no longer depends on it entirely. This is one reason why Florin keeps checking his phone even though the checking often disappoints him.

What Dopamine Really Does

Dopamine is a chemical messenger in the brain, one of many substances that nerve cells use to communicate. It is often described in popular articles as "the pleasure chemical", released whenever we enjoy something. This description is misleading. Research over several decades suggests that dopamine has more to do with learning and motivation than with pleasure itself.

Some of the most important evidence comes from studies in which researchers recorded the activity of dopamine-releasing nerve cells in animals as they learned to expect rewards. When an animal received an unexpected reward, such as a drop of juice, these cells became very active. But after the animal had learned that a particular signal, such as a light or a sound, always came before the juice, something changed. The cells became active when the signal appeared, not when the juice arrived. And if the signal appeared but the juice did not come, the cells' activity dropped below its normal level at the moment the juice should have arrived (this summarizes a well-known line of research).

Scientists interpret this pattern as a kind of learning signal. Dopamine cells seem to respond to the difference between what was expected and what actually happened, which researchers call a prediction error. A better-than-expected outcome produces a burst of activity. A worse-than-expected outcome produces a dip. An outcome that is exactly as expected produces little change. This signal helps the brain learn which cues predict rewards and which actions are worth repeating. It is, in a sense, the brain's way of updating its expectations.

Many researchers also distinguish between wanting something and liking it. Liking is the pleasure we feel when we actually get a reward. Wanting is the pull toward getting it, the motivation and craving. Evidence, much of it from animal studies, suggests that dopamine is more closely connected with wanting than with liking. This helps explain something Florin noticed: he wanted to check his phone very strongly, but he did not particularly like the checking. Wanting and liking can come apart. A habit can produce strong wanting even when it produces little liking.

It is important to say that this picture is still a simplification. Dopamine is involved in many brain functions, including movement, and scientists continue to debate exactly how its role in learning and motivation works. But the broad idea, that dopamine is closely linked with learning about rewards and with motivation, rather than simply with pleasure, is widely accepted.

The Pull of the Unpredictable

There is one more feature of rewards that helps explain Florin's habit, and it is one of the oldest findings in the study of learning. In the twentieth century, researchers who studied animal behaviour discovered that rewards given on an unpredictable schedule produce particularly strong and persistent behaviour. If a pigeon or a rat receives food every time it presses a lever, it presses steadily. If it receives food only sometimes, after an unpredictable number of presses, it often presses at a high and steady rate, and keeps pressing for much longer when the food stops coming.

One explanation, still discussed by scientists, connects this with the prediction error. When rewards are predictable, the brain soon learns exactly what to expect, and the learning signal becomes small. When rewards are unpredictable, every response holds the possibility of a surprise, and the brain keeps paying attention. Some responses bring nothing. But every now and then, something good arrives, and the uncertainty itself keeps the behaviour going.

Florin's phone checking is a clear example. Most of the time, when he checks, there is nothing much: posts he does not care about, no new messages. But sometimes there is something: a message from a friend, an interesting picture, a comment on something he posted. He cannot predict when these will appear. So every check holds the possibility of a reward, and his brain keeps pulling him back to look. This is the same pattern that keeps people pulling the handles of gambling machines, though usually much less harmful.

Understanding this does not make the pull disappear. But it can change how we see it. Florin had been blaming himself for weakness. Now he could see that his brain was responding exactly as brains are built to respond to unpredictable rewards. The pull was not a personal failing. It was the predictable result of a learning system meeting a phone that offers rewards at unpredictable moments.

This understanding also suggests ways to weaken such habits. If the pull comes from unpredictable rewards, reducing the cues that trigger checking, making checking a little harder and finding other sources of the small rewards it provides can all help. So can choosing particular times to check, which makes the rewards more predictable and therefore less gripping. We will look at these practical steps later in the chapter.

Florin Changes His Rewards

After learning about unpredictable rewards, Florin tried some changes. First, he reduced the cues. He moved the app off the first screen of his phone, so that he did not see it every time he unlocked the phone. He turned off all notifications except calls and messages from close family. He kept his phone in a drawer while he was working on a design, taking it out only during breaks.

Second, he made the rewards more predictable. Instead of checking whenever he felt the urge, he chose three times a day to check: after lunch, mid-afternoon and in the evening. At these times, he allowed himself to scroll freely for ten minutes. At other times, when the urge came, he reminded himself that he would check at the next scheduled time. Knowing that the next check was coming made the urge easier to bear.

Third, he looked for other sources of the small rewards that checking had given him. He realized that checking often gave him a tiny break from concentrated work, a moment of connection with friends and a small burst of novelty. He began to take short breaks away from his screen, standing up and stretching or making a drink. He arranged to have lunch with colleagues more often. And he started a small sketchbook, where he drew quick sketches during breaks, which gave him the novelty and creativity he had been seeking from the phone.

The first week was difficult. The urge to check came often, and Florin felt restless. But by the third week, the urges had become less frequent and weaker. By the second month, he was checking his phone far less than before, and he felt calmer and more focused at work. "The strange thing," he says, "is that I enjoy the scheduled checks more than I used to enjoy the constant ones. When I only look three times a day, there is actually something new to see."

Florin's last observation fits this picture. When rewards became less frequent and more predictable, each one became more satisfying, while the pull between them weakened. He had changed not only his habit, but his relationship with the rewards that had built it.

Imke and the Walk With a Story

Imke is fifty and works in the accounts department of a hospital. Her doctor suggested at a check-up that more regular physical activity would be good for her health, and she decided to start walking for half an hour every evening. She knew the benefits: better health, better sleep, more energy. But those benefits were far in the future. In the moment, after a long day at work, walking felt like a chore. Within two weeks, she had stopped.

Imke's problem was a classic one. The rewards of walking were delayed, while the rewards of staying on the sofa were immediate. Her brain, like all brains, gave much more weight to the immediate reward. So the new habit had nothing to strengthen it in the moment, and it faded.

A friend suggested a solution. Imke loved listening to long stories read aloud, but she rarely had time for them. Her friend proposed that she listen to them only while walking. The stories would be her immediate reward for walking, and she would not allow herself to listen at any other time. Some studies have found that linking a behaviour people want to do more of with something they enjoy, and allowing the enjoyable thing only during that behaviour, can help them do it more often, though the effects vary from person to person.

Imke tried it. She chose a long, gripping story and began to walk each evening while listening. Within a few days, she found herself looking forward to the walks, because she wanted to know what happened next in the story. Some evenings, she walked for longer than she had planned, because she did not want to stop at an exciting moment. The story had given the walk an immediate reward that her brain could feel.

After two months, walking had become a habit, triggered by the cue of arriving home and putting on her walking shoes. Imke noticed that, by then, she also enjoyed the walking itself: the fresh air, the movement and the feeling of tiredness afterwards. The story had helped to build the habit, and then the habit had begun to produce its own rewards. "I tricked myself into walking," she says, "and then I found I liked it." It is worth adding that anyone starting a new exercise routine should follow their doctor's guidance about what is suitable for them, as Imke did.

Kaveh and the Evening Reward

Kaveh is thirty-five and works from home as a translator. He has developed a habit of rewarding himself at the end of each working day with something sweet: a chocolate bar, a slice of cake or a bowl of ice cream. It began as an occasional treat after a hard day. Now it happens every day, and he has noticed that he feels a strong craving for something sweet as soon as he closes his laptop, even if he is not hungry.

Kaveh's habit shows how a reward can become linked with a cue. The cue was closing his laptop at the end of the day. The routine was eating something sweet. The reward was the taste, the comfort and the sense of marking the end of work. Through repetition, the cue began to trigger a craving, the wanting that dopamine is involved in, even before the reward arrived.

Kaveh did not want to give up all treats, but he wanted the daily sweet habit to be less automatic. He realized that the real reward was not the sugar itself, but the feeling of marking the end of the working day and shifting into rest. So he looked for other ways to mark it. He began to end his workday with a short ritual: closing the laptop, putting it away in a cupboard, making a cup of herbal tea and stepping out onto his balcony for a few minutes.

For the first couple of weeks, the craving for something sweet still came when he closed the laptop. He noticed it, acknowledged it and let it pass while he made his tea. Gradually, the new ritual began to provide the reward his brain was looking for: a clear signal that work was over and rest had begun. The craving weakened. Kaveh still has sweets sometimes, but now as a choice rather than an automatic response.

"I thought I was craving chocolate," Kaveh says. "I was actually craving the end of the day. Once I found another way to end it, the chocolate became much less important." Kaveh's story shows that understanding what a reward really provides can open the way to replacing it with something else that provides the same thing.

Practical Steps: Working With Rewards

The first step is to find the real reward. For the habit you want to change, ask what it actually gives you. Is it pleasure, relief, comfort, a break, connection, novelty or a sense of completion? The real reward may be different from the obvious one, as it was for Kaveh and Matilde.

The second step is to offer the brain a substitute reward. If you want to change a habit, look for another behaviour that provides the same real reward. A walk can provide a break. A conversation can provide connection. A short ritual can mark the end of the day. The brain is more willing to change a routine when the reward is still available.

The third step is to add immediate rewards to new habits. For habits whose benefits are delayed, like exercise or saving, look for ways to add something enjoyable in the moment. Like Imke, you might pair a new habit with something you enjoy and allow that enjoyable thing only during the habit.

The fourth step is to make unpredictable rewards more predictable. For habits driven by unpredictable rewards, like checking phones or emails, choose specific times for them. This tends to weaken the constant pull and can make each check more satisfying.

The fifth step is to reduce the cues that start the wanting. Since cues can trigger cravings even before a reward arrives, removing or hiding them, as Florin did with his app and notifications, can reduce the wanting itself.

The sixth step is to notice wanting and liking. When you feel a strong pull toward a habit, ask yourself whether you actually enjoy it, or only want it. Noticing the difference, as Florin did, can loosen the pull, because it shows that the craving is a learned signal rather than a promise of real pleasure.

The Myth of the Dopamine Detox

In recent years, a popular idea has spread that people can "reset" their dopamine by avoiding all enjoyable activities for a period, sometimes called a dopamine fast or detox. Supporters claim that this will lower some kind of overload and make ordinary activities feel rewarding again. This idea, at least as it is often described, is a misunderstanding of how dopamine works. Dopamine is not a substance that builds up and needs to be flushed out, and there is no good evidence that avoiding pleasure for a day resets the brain's chemistry.

At the same time, the practical core of the idea is not entirely wrong. Taking breaks from habits driven by constant, unpredictable rewards, such as phones and screens, can help people notice the pull of those habits and reduce their automatic grip. This works not because dopamine is being cleaned out, but because removing cues and breaking routines weakens the habit's links, as we have seen in this chapter and the last. It is worth being careful with claims that dress sensible advice in scientific-sounding language that is not accurate.

It is also important to repeat that some reward-driven patterns are much stronger than ordinary habits. Addictions to substances, gambling and some other activities involve the brain's reward systems in powerful ways that can be very hard to change alone. If you feel that a pattern of behaviour is out of your control, is harming your health, your finances or your relationships, or that you need more and more of something to feel satisfied, please talk to a doctor or another qualified professional. Help is available, and seeking it is a sign of strength.

A Short Exercise: A Reward Audit

This exercise helps you understand the rewards behind one of your habits, and find possible substitutes. It takes about fifteen minutes.

Choose one habit you would like to change. At the top of a page, write it down. Then make three columns. In the first, write "What I think the reward is". In the second, write "What the reward might really be". In the third, write "Other ways to get it".

In the first column, write the obvious reward: "the taste of chocolate", "seeing new posts", "the comfort of the sofa". In the second column, think more deeply. What does the habit really give you? A break? Relief from boredom or stress? Connection? A sense of finishing something? Novelty? Write down as many possibilities as you can.

In the third column, for each real reward you identified, write one or two other ways you could get it. "A break: a short walk, stretching, looking out of the window." "Connection: phoning a friend, chatting with a colleague." "End of work: a short ritual, tea on the balcony." Choose one substitute to try in the coming week.

Finally, notice wanting and liking. Next time you feel the pull of the habit, ask yourself honestly: do I like this, or do I just want it? Write down your answer afterwards. Florin did this exercise for his phone habit. In the first column, he wrote "seeing new things". In the second, he wrote "a break from concentrating, a bit of novelty, feeling connected". In the third, he wrote "stand and stretch, sketchbook, lunch with colleagues". Under the question about wanting and liking, he wrote: "I want it a lot. I like it about a quarter as much."

Chapter Summary

Habits are built and strengthened by rewards, and immediate rewards are much more powerful than delayed ones, which is why unhelpful habits often form easily and helpful ones slowly. Once a habit is strong, it may continue even when the reward has become weak. Dopamine is better understood as involved in learning and motivation than as "the pleasure chemical": dopamine cells respond to the difference between expected and actual rewards, and many researchers distinguish wanting from liking, with dopamine more closely linked to wanting. Rewards that come unpredictably produce especially strong and persistent behaviour.

Florin and his constant phone checking, Imke and her walk with a story and Kaveh and his evening sweets all found that understanding the real reward behind a habit, offering substitutes, adding immediate rewards to new habits and making unpredictable rewards predictable helped them change. The popular "dopamine detox" misunderstands how dopamine works, though breaks from habits can still help. Patterns that feel out of control deserve professional support.

In the next chapter, we will look at a question many people ask when they start a new habit: how long will it take? The popular answer, twenty-one days, turns out to be a myth.