Warning: This book is about your brain, not about other people's brains. If you are in the habit of blaming your neurochemical ups and downs on others, you will not find support here. But you needn't blame yourself, either---you can make peace with your mammalian neurochemistry instead of finding fault with it. This book shows you how.

Chapter 1 Your inner mammal

內啡肽，通過努力或者痛苦獲得的愉悅

催產素，社會信任，鏈接

血清素? 尊重 認可 更高的最求

Dopamine produces the joy of finding things that meet your needs--the "Eureka! I got it!" feeling.

Endorophin 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.

Familiar Neural Pathways Are Easy to Travel... but That's Not Always Good. You may find yourself liking things that are not especially good for you and fearing things that actually are good for you. Why would a brain that evolved for survival build such quirky circuits?

Because we're designed to store experiences, not to delete them. Most of the time, experience holds important lessons. It helps you go toward whatever helped in the past and avoid whatever hurt. But the pathways of past experience can also mislead.

But those superhighways don't always take you where you want to go. Sometimes they lead you to unhappy chemicals just when you were hoping to feel good. You can enjoy more happy chemicals if you blaze new trails through your jungle of neurons. It may be harder than you expect, but it's easier when you know your equipment.

When you were young, you built new circuits easily. In adulthood, building a new circuit is as hard as slashing through a dense rainforest. Every step requires huge effort, and the new trail you worked so hard for disappears into the undergrowth if you don't use it again soon. All this slashing may feel like a waste of time when you already have a network of superhighways to use instead.

Repetition develops a neural trail slowly, the way a dirt path hardens from years of use. So how can you build new pathways? The answer is simple: Feed your brain new experiences again and again. Repetition will build the circuits you want. No one can build them for you, and you cannot build them for someone else.

You might wish to escape unhappiness forever, but it's useful to know that unhappy chemicals are as essential to your survival as happy chemicals. Your brain needs unhappy chemicals to call attention to threats and obstacles, just as it needs happy chemicals to call attention to opportunities. You are designed to survive by seeking happy chemicals and avoiding unhappy chemicals.

We anticipate bad feelings in order to prevent them. But unhappy chemicals persist no matter how well you meet your needs, because your survival is threatened as long as you're alive.

The mammal brain never stops scanning for potential threats. When you're safe from physical threats, your brain scans for social threats. Mammals survive because the bad feeling of cortisol alerts you in time to avoid potential threats.

Cortisol communicates pain and the expectation of pain. It motivates you to do whatever it takes to make the bad feeling stop.

Doughnuts trigger happy chemicals because fat and sugar are scare in nature. The good feeling distracts you from the bad feeling, which makes it seem like the threat is gone for the moments you are eating the doughnut.

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. It didn't evolve for you to sit around and accept it, after all. But you can build the skill of doing nothing during a cortisol alert, even as it begs you to make it go away by doing something. Waiting gives your brain a chance to activate an alternative. A virtuous circle starts in that moment.

The pain of resisting a baby eases once a new habit forms. You can do that in forty-five days if you repeat a new though or behavior every day without fail. If you miss a day, start over with Day one. The new choice will not make you happy on Day one, and it may not make you happy on Day Forty-Five, it cannot trigger happy chemicals constantly. But it will invite enough electricity to free you from a vicious cycle.

It's easy to see vicious cycles in others. That's why we're tempted to take charge of other people's happiness. But you cannot reach into someone else's brain and make new connections for them, nor can they do that for you. If you focus on other people's brains, you may fail to make them happy and fail to make yourself happy. Each person must manage his or her own limbic system.

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 statue.

We must transition from childlike dependence to mature independence. That can feel like a survival threat to the part of your brain that expects to be taken care of. This motivates people to find adult love, and that keeps our genes alive. But the interdependence of mature love never measures up to the dependence of your brain's first circuits.

Chapter 2 Meet your happy chemicals

You are constantly deciding what is worth your effort and when it's better to conserve your effort. Your dopamine circuits guide that decision. You might wish the good feeling of dopamine just followed all the time, but that wouldn't really benefit you.

You may not have a "Wow!" feeling about berries, because sweetness is no longer a rare taste. Your brain saves your energy for rewards that are scarce in your life experience. I get a rush of excitement when I see the first cherries of the season, but my excitement doesn't last. Looking at cherries can't make me happy all the time. My brain saves its dopamine for things relevant to my present needs instead of wasting it on things already available.

We all live with the fact that dopamine is soon metabolized and you have to approach a reward again to get more.

Dopamine evolved to store new information about rewards. When there's no new information, there's no need for dopamine.

The monkey had learned to except juice. It no longer made them happy, but losing it made them mad.

Cocaine stimulates more dopamine than real life. It gives you the thrill of finding berries or finishing a marathon without leaving the couch. You get the excitement of accomplishment without having to accomplish anything. Natural rewards feel less exciting if your brain learns to except an artificial jolt.

The verbal part of the brain is not needed for a dopamine circuit to unleash the energy needed for the job.

Dopamine unleashes your reserve tank of energy when you see a way to meet a need. Even when you're just sitting still, dopamine motivates you to scan a lot of detail to find a pattern that's somehow relevant to your needs.

Each brain has built expectations about survival rewards and the steps it takes to reach them. When you moved toward your expected reward, dopamine makes it feel good.

Endorphin did not evolve to motivate self-inflicted pain. It evolved to escape pain.

It's nice to know about nature's morphine when you see disturbing footage. It reminds you that endorphin exists not for partying but for momentary respite in the struggle for life.

A broken heart doesn't trigger endorphin the way a broken bone does. Endorphin did not evolve to mask social pain. In the past, daily life held so much physical pain that social pain was secondary. Today, we suffer less from the pain of manual labor, predator attack, foraging accidents, and deteriorating disease. We have more energy to focus on painful social disappointments. This leaves us feeling that life is more painful even as it's less painful.

Adrenaline is outside the scope of this book because it does not cause happiness. It causes a state of arousal, as if your body is stepping on the gas. Some people learn to like that feeling, but it is not a signal that something is good for you. It is a signal that something is extremely relevant to survival, whether good or bad, and thus requires your energy.

Mammals live in herds and packs and troops because there's safety in numbers. If they are separated from their group mates, their oxytocin falls and they feel bad. A herd animal panics when it can't see at least one of its group. When it rejoins them, a surge of oxytocin relieves the cortisol.

A herd only protects you if you follow the crowd and run when they run. If you insist on seeing the lion for yourself before you run, you are less likely to survive. Natural selection built a brain that can trust the judgement of others. But herd behavior has a downside that's obvious to humans. We worry about jumping over cliffs when the other lemmings jump. We worry about group-think and gangs and codependence. We override our herd impulses and strike out on our own. But we often feel like a lamb among lions because of our urge for oxytocin.

Oxycotin is the pleasure of letting down your guard near those you trust. It's not the conscious decision to trust, but the physical feeling of safety you get from proximity to trusted others. Oxycotin flows in a gazelle surrounded by it's herd and a monkey having its fur groomed. Social alliances promote survival, and mammals evolved a brain that makes it feel good. A human brain can abstract, so we can enjoy the feeling of social support without others being physically present. Our oxytocin pathways build from life experience. We mammals surge with oxytocin at birth, which builds our core attachment circuits. We wire ourselves to trust whatever we experience while our oxytocin is flowing. That's how a young mammal transfers its attachment from its mother to its herd. Humans often leave the herd we grew up in, but our brains still crave oxytocin.

Social alliances transform threatened feelings into safe feelings thanks to oxytocin.

Serotonin promotes survival whether it's up or down by balancing energy expenditure with food intake.

Social dominance is the calm, secure expectation that you will get what you need. Cortisol is the sense that something awful will happen if you don't act now.

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. The point is not that you should push your assess to resources. When access looks secure, you feel good for a moment, and then you look for ways to make it more secure. You may get annoyed when you see others trying to secure their position. But when you do it, you think,"I'm just trying to survive."

Securing resources is tricky for creatures that live in groups. A solitary reptile can just lung at food without worrying about others. If a group-living mammal lunged at food, it might crash into a bigger, stronger individual who would attack it. Avoiding injury promotes survival more than any one bite of food. So the impulse to compare yourself to others and decide whether you're stronger or weaker is more pressing than the impulse to eat. When a mammal sees that it's weaker, it restrains itself until the other has eaten. When a mammal sees that it's stronger, its serotonin surges and it lungs at food.

Serotonin is the feeling of being important. We see how much others like to feel important, but we hate to see this in ourselves. It helps to know that our brain was naturally selected to seek social dominance, because brains that did so made more copies of their genes. We strive to avoid conflict because aggression can wipe out your genes. So the mammal brain keeps calculating social data, and when you find a safe way to assert yourself, it rewards you with serotonin. A big human cortex tries to stimulate serotonin with abstractions rather than one-on-one showdowns, such as "pride," "confidence," or "self-respect." It feels good...even if you hate to admit it. Noticing your mammalian urge for serotonin is a valuable skill.

One person may feel respected for his appearance, while another feels disrespected, even if the two people look exactly the same. Our neurochemicals depend on the expectaton circuits we've built.

3. WHY YOUR BRAIN CREATES UNHAPPINESS

The human brain stem and cerebellum are eerily similar to a reptile's brain. Nature adapts old parts rather than starting over. We still use the reptile brain for the jobs it is good at, like metabolic balance and alerting to potential harm. Mammals added a layer onto the reptile brain that makes social life possible, and humans added on a layer that matches patterns among the past, present, and future. Your reptile brain lies where these higher layers and your body intersect, so it's not surprising that you find patterns in the social world that give your body a threatened feeling. Many people end up feeling threatened more than they'd like to, so it helps to know how your threat detector works.

How Cortisol Works

Cortisol is your body's emergency broadcast system. It creates the feeling humans call "pain." Pain gets your attention. It feels bad because that works---it focuses your attention on whatever it takes to make it stop. The brain strives to avoid pain by storing details of the experience so you know what to look out for in the future. When you see things associated with past pain, your cortisol starts flowing so you can act in time to avoid future pain. A big brain can generate many associations, so it can anticipate many possible sources of pain.

When cortisol surges, we call it "fear," but when cortisol dribbles, we call it "anxiety" or "stress."

You might think you'd be free from cortisol if the world were in better shape. But your brain sees every disappointment as a threat, and this response has value. It alerts you in time to prevent further setbacks and disappointments.

快樂元素的新習慣 45天的不間斷堅持（錯過一天重新計算）

多巴胺的快樂

1.肯定自己每天小的進步(每天點燃自己的小火花，最后也能燃成火苗)

大腦回路傾向于自我批評

不要通過跟別人比較，來取得成就感

2. 每天行動一小步

3.把難辦的事情分成一小部分去做

4.不斷調節難易度，適合自己的難度是最好的

內啡肽的習慣

1. 笑

笑是恐懼的釋放，能制造安全感

2.偶爾哭泣可以釋放緊張情緒，但不要經常哭泣，這會造成大量皮質醇

3.運動的多樣化

人體有三層肌肉，不同的運動可以鍛煉不長使用的肌肉部位。

4.拉伸

包括你平時不注意的部位，手指腳指頭，耳朵等...緩慢的移動可以確保你肌肉的均衡發展

5.使鍛煉有趣

快樂有趣的運動，能幫助你堅持

建立新的催產素回路

1.建立"代理"的信任

和動物，數字朋友，人群建立信任，這樣的信任不像人與人之間的友誼，可能會讓人失望。

2.放置墊腳石

The goal is not to trust blindly and get disappointed. The goal is to build positive expectation.

For forty-five days, craft reciprocal exchanges that build stepping stones toward trust with difficult people. You can't predict the results since you can't control others. But you will expend your sense of control over the trust bonds in your life. This is hard work, and it may not feel good in the short run. But in the long run, it builds confidence that you can do something about those thorns in your side.

You might start by just making eye contact with that person who's making your life difficult.The next day, you could comment on the weather, and add a smile the day after that. It could take a week to build up to a shared chunkle about traffic, and even that may stir up bad feelings that are curiously strong. But you will continue making neutral contact--nither venting anger nor rushing to please. In forty-five days, you will have built a new shared foundation. You may always need to limit your trust in this person, but you will be able to relex in his presence the way gazelles relax in a world full of lions.

3.做一個值得信任的人

被別人信任和信任別人一樣，能產生催產素。但你不需要成為別人的救世主，嚴格遵守自己的諾言就可以。

Do not spend a lot of time seeking approval. Simply honor your commitments, and then pause to enjoy being a person who honors her commitments.

4.建立信任認證系統

建立信任，但是要去驗證真假，這樣能幫自己提高信任機制的可信度。

Verifying makes it possible to develop trust with strangers. If you're too nice to verify, you get stuck inside the safe barbor of people you already trust.

If you do it for forty-five daus, you can't predict what others will do, but you can build confidence in your ability to extend your trust circle. Instead of being confident to the niche where you can trust everyone, you have a tool for taking controlled risks.

5. 保持信息溝通

建立血清素的回路

1. 對自己所做的表達驕傲

It wants respect from others because that has survival value.

Taking pride in yourswlf means more than just thinking iy silently. It means daring to say,"Look what I did!"to another living soul. People often protect themselves by insisting that social respect doesn't matter or that it's hopeless unfair. But these rationales don't soothe the mammal brain's longing for the sense of security that social respect brings.

2.享受你所處的位置，得勢或者失勢

3.注意到自己對別人的影響

不要批評和控制別人，注意到自己對別人的好的影響，但不要期望得到回報或者感謝。

不要說我之前告訴過你這類話

選擇想要養成的習慣參考思路

1.長期收獲和短期收獲

You will always have ups and downs because your brain is designed to continually seek rewards and avoid pain.

錯誤想法

1.你為別人的快樂負責

你首先對自己的快樂習慣和行為負責

Taking the reins of your own life is your only real choice. You cannot control the reins for other lives or expect others to manage yours.

2.對自己的快樂擁有掌握權，不責備外界環境

When you put yourself in charge of your own happiness, you have power.

Fixing the system seems to be more fun and more righteous than fixing yourself.

You are simply a mammal among mammals.

3.不要把快樂建立在打到某個目標上(我只有...我才會快樂)

幫助自己的小工具

1. Mirror

尋找榜樣，模仿對方身上所擁有你想要養成的習慣

2.平衡四種happy chemical

Dopamine多巴胺

Endorphin 內啡肽

Serotonin 血清素

Oxytocin 催產素

3.嫁接

將新的習慣嫁接到舊的愛好中，更容易成功。

4.有限的精力

新習慣的養成會耗費更多的精力,把養成的習慣，放在一天精力最充沛的時候

If you run out of energy before meeting your daily commitment, you will find reasons to ditch it. So make your new habit the top-priority use of your energy for forty-five days, even if you have to relex another priority.

One way to ensure energy is to schedule your new habit first thing in the morning.

Mental energy is a lot like physical energy. It depends on glucose, and it takes time to restore once deleted. You easily succmb to temptions when your mental energy is depleted.

樂趣

找到事物的樂趣，能幫你更好的堅持下去

將任務切分成小目標

不要貪多，一口氣吃成胖子，一小模塊完成，最后能全部完成

satisfice 對目標只求過得去，不求完美

satisficing is better than optimizing

提前做好計劃

預估到你可能需要的習慣，提前去培養

效果可視化

Once your new pathway is established, your happy habit will feel so natural that you will literally forget to feel bad.

Let in the Good讓美好進入

Learning from your mistakes has value, of course, but your error-analysis habit can crowed out your awareness of the good. You can focus on what goes wrong in the world so intently that you don't see what goes right.

調整期待

Each choice has advantages and disadvantages. Once you pick, you get to see the disadvantages of that choice up close.

Your happy chemicals will not surge all the time, but you do not need to be having a "peak" experience at every moment. You can accept the inevitable dips in your happy chemicals instead of believing something is wrong. You don't have to mask the dips with unhealthy habits. You can just take them as evidence that your inner mammal is looking out for you in the best way it knows how.