Habits of a Happy Brain Summary (Review & Book Notes)

Tomas Laurinavicius
Updated on March 16, 2024

Today I want to share my review and book notes of Habits of a Happy Brain by Loretta Breuning.

We have a mammalian brain that is designed to seek survival. We’re not meant to be happy but understanding emotional chemicals can help us become happier.

Understanding serotonin, dopamine, oxytocin and endorphin will explain why it’s natural to have emotional ups and downs. The author explains how to use habit theory to rewire our brain and produce happiness from within.

Biggest lesson: We have a mammalian brain that is designed to seek survival.


In her book, Habits of a Happy Brain, Loretta Breuning, Ph.D. explains how you can use the power of your brain to change your life for the better.

Drawing on the latest scientific findings, Breuning shows how the brain chemicals in your head really affect your happiness levels.

In addition, she explains how we can use our mind to change our brain, leading to better health, more energy, optimism and a better attitude towards life.

AuthorLoretta Breuning
Publication year2015
My rating⭐⭐️⭐️⭐️️
Buy on AmazonKindle

Notes & Quotes

When you feel good, your brain is releasing dopamine, serotonin, oxytocin, or endorphin. You want more of these great feelings because your brain is designed to seek them.

Each happy chemical triggers a different good feeling:

  • Dopamine produces the joy of finding things that meet your needs- the “Eureka! I got it!” feeling.
  • Endorphin produces oblivion that masks pain – often called euphoria.
  • Oxytocin produces the feeling of being safe with others – now called bonding.
  • Serotonin produces the feeling of being respected by others – pride.

The human limbic system is surrounded by a huge cortex. Your limbic system and cortex are always working together to keep you alive and keep your DNA alive.

Each of the happy chemicals motivates a different type of survival behavior:

  • Dopamine motivates you to get what you need, even when it takes a lot of effort.
  • Endorphin motivates you to ignore pain, so you can escape from harm when you’re injured.
  • Oxytocin motivates you to trust others, to find safety in companionship.
  • Serotonin motivates you to get respect, which expands your mating opportunities and protects your offspring.

The mammal brain motivates a body to go toward things that trigger happy chemicals and things that trigger unhappy chemicals.

You are always looking for a way to feel good, deciding whether to act on it, and them looking for the next best way of feeling good.

Nature tends to build on what’s there instead of starting over with a blank sheet. Mammals built onto the reptile brain and humans built onto the mammal brain. We humans have a large stock of extra neurons ready to wire in new experience.

You can keep building new neural pathways and thus keep fine – tuning your efforts to meet your needs. But man does not live by cortex alone. You need your limbic system to know what’s good for you.

Each time you have an experience, your senses take in the world and trigger electricity on your brain. That electricity flows in your brain like water flows in a storm – it finds the paths of least resistance. The paths you’ve already built give your electricity a place to flow, and that shapes your response to the experience.

Because we’re designed to store experiences, not to delete them. Most of the time, experience holds important lessons.

When you were young, you built new circuits easily. In adulthood, building a new circuit is as hard as slashing through a dense rainforest.

Each time a pathway is activated, it fires more easily. Repetition develops a neural trail slowly, the way a dirt path hardens from years of use.

You can stop  a vicious cycle in one instant. Just resist that “do something” feeling and live with the cortisol. This is difficult to do because cortisol screams for your attention.

You can do that forty-five days if you repeat a new thought or behavior very day without fail. If you miss a day, start over with Day One.

In humans, everything from holding hands to feeling supported triggers oxytocin. Orgasm does too. Sex triggers a lot of oxytocin at once, yielding a lot of social trust for a very short time.

Oxytocin is related to love in so many ways that it is often called the bonding hormone or the cuddle chemical.

Serotonin is stimulated by the status aspect of love –  the pride of associating with a person of a certain stature.

Endorphin is stimulated by physical pain, but you get a bit from laughing and crying too.

Something as small as failing to get a smile from the person you smile at can trigger surprising neurochemistry because your brain relates it to the survival prospects of your genes.

The urge for more did not start with “our society”. In fact, our ancestors never stopped seeking either. When their bellies were full, they looked for new way to meet their needs by making better arrows and stronger shelters.

“Euphoria” is a common description of the endorphin feeling. But this neurochemical did not evolve for good times.  Physical pain is what triggers it. You may have taken a bad fall and got up thinking you were fine, only to discover that you’re seriously injured. That’s the power of endorphin.

The larger a creature’s brain, the longer it remains helpless after birth. It takes time to fill a brain with useful connections.

With each social interaction, they update their circuits with oxytocin or cortisol. Over time, you “know who your friends are” because your neurochemicals react to individuals as “good for your survival” or “bad for your survival”.

Animals  only fight when both individuals believe  they are stronger. Conflict is usually avoided because animals are skilled at assessing  their  relative strength, and the weaker individual submits to avoid harm.

We scan for ways to enjoy the good feeling of social importance without the bad feeling of conflict.

Each  brain builds expectations that tell it when to forge ahead to meet its needs and when to hold back to avoid pain.

Every brain longs for the good feeling of serotonin, but the motivation is easier to see in others and can be difficult to see in yourself.

When you worry about the SATs or looking fat, cortisol creates the physical sense of imminent annihilation.

Each generation of humans can learn about danger from its own cortisol  surges. We learn about danger from our elders as well, but each generation trends to sneer at the fears of its elders and build fears of its own.

Your brain is a central clearing-house that links past pain to potential future pain.

Watching an action stimulates the same neural trail as executing the action.

We do not mirror everything we see in others. Mirror neurons  only fire when you watch someone get a reward or face a threat.

Mirror neurons allow us to feel other people’s pain. This has a benefit, as often suggested by empathy researchers, but it also has a cost.  You can get wired to suffer just by being around people who suffer. Even if your life is fine, mirroring builds a pathway to your cortisol.

For example, if your work is criticized at a performance review, you know your survival is not literally threatened, but cortisol makes it feel that way.

To make matters worse, just belonging to the herd doesn’t  make your mammal brain happy. It wants to be noticed.

No other creature is born so far from being able to survive  on his own.

You may say you don’t care about status, but when a high-status person notices you, your happy chemicals soar.

The urge for specialness might seem annoying in others, but in yourself, it just feels like fairness.

In the state of nature, comparing yourself to others promotes survival. It protects you from getting into fights that you are likely to lose.

We are designed to scan for inputs we’ve already experienced as important rather than wasting our attention on whatever comes along.

Your dopamine surges at first, but continued rewards don’t trigger continued dopamine. When your dopamine droops, it feels like something is wrong with the world, or with you.

Starving yourself stimulates endorphin, but you have to starve more and more to keep getting that feeling. Starving triggers endorphin because it helped our ancestors forage in lean times. The ability to seek on an empty stomach promotes survival. If you’ve ever missed a couple of meals, you may have started feeling little high. The good feeling stopped as soon as you ate something, but you ate anyway because you know that nutrition is necessary for survival.

But when you decide to get control of your habit, you may be shocked to find that these allies do not support you. They may even undermine your efforts to conquer your habit. Many people end up continuing an unhealthy habit rather than risk their  friendships.

Animals stick with groups that are full of internal conflict because they are so threatened by external conflict. The more threatened you feel by life outside the group, the more pain you tolerate from within it.

Distraction can make you feel good just by interrupting the electricity in a bad loop.

You can stop a vicious cycle in one instant, simply by doing nothing. That teaches your brain that you will not actually die without the old habit. You learn that threatened feelings do not kill you.

The first step to happier habits is to do nothing when your cortisol starts giving you a threatened feeling. Doing nothing goes against your body’s deepest impulse, but it empowers you to make change in your life.

You were born with a lot of neurons but very few connections between them. Connections built as you interacted with the world around you, and they make you who you are.

Old brains build new learning only when a person engages in a lot of repetition.

A synapse is the gap between one neuron and the next. The electricity in your brain only flows if it reaches the end of a neuron with enough force to jump across that grap.

You didn’t decide consciously which synapses to develop. It happens in two ways:

  1. Repetition, which develops a synapse gradually
  2. Emotion, which develops a synapse instantly

Emotions are chemical molecules that can change a synapse immediately  and permanently.

Richly interconnected networks are the source of our intelligence, and we create them by building new branches onto old trunks instead of building new trunks. So by the time you are seven, you are good at seeing what you have already seen and hearing what you have already heard.

Five ways experience changes your brain:

  1. Experience insulates young neurons with myelin, so they’re superfast conductors of electricity.
  2. Experienced synapses are better at sending electricity to neighboring neurons, so you’re better at lighting up a path you’ve lit up before.
  3. Neurons atrophy if they’re not used, so you rely more heavily on the neurons you’ve used.
  4. New synapses grow between neurons you use, so you make connections.
  5. Receptors grow and atrophy, so it’s easier to process the feelings you experience repeatedly.

Your attention is limited. If you invest it in one place, you have less to invest in alternatives. It takes little attention  to follow a familiar path, but shifting to the unfamiliar makes heavy demands on your attention.

The two strategies often work together because we feel good when we master a skill with conscious intent. We feel bad when we fall short of a goal we consciously pursue.

Experiences that are neurochemical or repeated build circuits that endure. Experiences in youth build supercircuits.

Our cortex is huge because we are designed to fill it with acquired knowledge. We are not meant to run on preloaded programs.

Animals with short periods of early dependency need inborn survival skills, so they can only survive in the ecological niche of their ancestors. They typically die outside that niche.  Humans are born ready to adapt to whatever niche they’re born into.

Of all the ways to feel good in the world, the ones you’ve already connected are the ones that get your attention.

We all end up with quirky circuits like mine because we build on the connections that are already there. Our happy chemicals pathways feel important so it’s hard to realize that they are just accidents. Anything that turns on your happy chemicals feels precious, which can lead to behaviors that are hard to make sense of. If can even lead to behaviors that are destructive.

Anything that works gets wired in, even behaviors that could be counterproductive  in the long run. If a bad behavior gets a reward, young  brain tags that behavior  as useful for survival.

Emotion is a Catch – 22. Anything that feels good now will have side effects later.

If you expose yourself to something over and over, it can “grow on you” . You can come to like things that are good for you even though you don’t like them instantly.

But who wants to repeat something over and over if it doesn’t feel good? Usually, people don’t, especially when they’re already feeling bad. This is why rely on the circuits built by accidents of experience. Your accidents will shape you unless you start repeating things by choice.

A habit that will feel good later is hard to start now.

Celebrating small steps triggers more dopamine than saving it up for one big achievement. Big accomplishments don’t make you happy forever, so if you always tie happiness to a far – off goal, you may end up frustrated.

You can decide to be worthy of your own applause and enjoy  the feeling, even if just for a split seconds.

Laughing stimulates endorphin as it spontaneously convulses your innards. Find out what makes you laugh, and make time for it.

Laughter is a release of fear. Imagine laughing with relief after a close call with a snake.

Crying releases endorphin because of the physical exertion. I do not suggest making a habit of crying – it comes with a lot of cortisol too.

Varying your exercise routines is a good way to trigger endorphin. It takes strain to trigger endorphin, and if you keep straining the same place, you risk injury. If you work new places with new exercise, moderate exertion can stimulate endorphin.

Free yourself from performance anxiety for forty-five days. You may like it so much that you want to try another variation for another forty-five days.

Endorphin is also stimulated when you stretch.

Mild stretching brings circulation into constricted areas.

Tai chi and Qi Gong are so slow that you may thing they’re not real exercise.

Every time you feel good about an animal, a crowd, or a digital relationship, tell yourself “I am creating this good feeling.”

For forty-five days, craft reciprocal exchanges that build stepping stones towards trust with difficult people. You can’t predict the results since you can’t control others.

When other people trust you, it feels good whether or not you trust them. You can enjoy more oxytocin by creating opportunities for people to trust you.

You could applaud yourself, but the brain is not easily tricked by hollow self-respect. It wants respect from others because that has serotonin boots. Social recognition is unpredictable and fleeting.

Whether you get a lot of social regards or a little, your brain will keep longing for it. That’s what your mammal brain does.

Without criticizing or controlling, you can notice when others mirror your goods example. Don’t expect credit or even a thank you. Just quietly enjoy.

This may sound arrogant, but every mammal brain longs for social significance. Everyone wants to have an impact on the world and fears dying without a trace.

Getting rid of the clock is a great way to experiment with control, because you can’t control time. We all have habits for managing the harsh reality of time.

  1. Start an activity without having an exact time you need to stop. Finish the activity without ever checking the clock the whole time. It’s over when you feel like it’s over.
  2. Set aside a time each day to spend with no plan.
  3. Designate a day you can wake up without looking at the clock and continue through your day with no time – checking.

We are always trading off the safety of the known against the promise of the unknown.

Appreciating what you have is difficult to do because the mind naturally seeks what it doesn’t have.

At the zoo where I volunteer, animals often break in, and rarely break out.

You may have the illusion that happiness is just handed to a lucky few, while others are wrongly deprived of it.

You don’t realize that suffering is just a circuit your mammal brain built  because it was rewarded in your past.

We mammals naturally compare ourselves to others.  But we never really know the inside story about other people’s lives. Even if you did, it wouldn’t make you happy.

If you don’t look for the good in the world, it will easily escape your attention.

When you blame your frustrations on abstract institutions, it helps you avoid blaming real people you know in person.

So I faced the inevitability of human frustration. Each brain sees itself as the center of the world, though it is just 1 of 7 billion.

Mirror people who already have the habits you want. Find someone with a habit you’d like to create, and watch them. Your mirror neurons will light up and spark your circuits. This is a great way to overcome the inertia of those virgin neurons.

Your brain only has a limited amount of energy. You can enhance it with exercise, sleep, and good nutrition, but it will still be limited. New behaviors consume more energy than you expect.

Mental energy is a lot like physical energy. It depends on glucose, and it takes time to restore once depleted.

Anything connected to your DNA triggers happy chemicals.

I know reaches the top of a mountain by mentally dividing it into quarters. He focuses his attention on the next quarter-post and mentally celebrates when he reaches it. This makes no logical sense, because the mountain is just as high. But chunking can trick your brain into feeling good even when you’re not really fooled.

When I find it hard to stop optimizing, I remind myself that the 1978 Nobel Prize in Economics was awarded to a mathematical proof that “satisficing”, is better than optimizing. Herbert  Simon showed us why embracing a satisfactory solution is better than investing in an endless analysis.

I would not be alive today if it weren’t for antibiotics, so I was surprised to learn that they did not even exist a decade before I was born.

Your brain builds expectations about what will make you happy and it sees the world through the lens of those expectations.

If you decide to be happy, your brain will find things to be happy about. You will still have frustrations and disappointments, but you will find ways to make yourself happy anyway.

It’s not easy to manage this brain we’re inherited from our ancestors. It’s the challenge that comes with the gift of life.

👉 Buy Habits of a Happy Brain

Tomas Laurinavicius

Hi! I'm Tomas, a writer and growth marketer from Lithuania, living in Spain. I'm always involved in multiple projects driven by my curiosity. Currently, I'm a marketing advisor at Devsolutely and a partner at Craftled, building Best Writing and Marketful. Let's connect on X and LinkedIn.