要点解析：感恩的科学与如何培养感恩习惯

欢迎来到《赫伯曼实验室精华》，我们将重温往期节目，探讨那些对心理健康、生理健康和表现最具影响力且可操作的科学工具。我是安德鲁·赫伯曼，斯坦福医学院神经生物学和眼科学教授。今天，我们将全面探讨感恩的科学。现有大量数据表明，有效的感恩实践能以积极方式影响众多健康指标，包括心理和生理健康。但在筹备本期节目时，我对'何为有效感恩实践'的发现完全出乎意料。

Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science based tools for mental health, physical health, and performance. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, we are talking all about the science of gratitude. There's now a wealth of data showing that having an effective gratitude practice can impact a huge number of health variables, both mental health and physical health in positive ways. However, in researching this episode, I was completely surprised as to what constitutes an effective gratitude practice.

我和许多人一样，原以为有效的感恩实践无非是写下几件或许多件值得感恩的事，或思考这些事，又或在列清单时努力具身化或感受感恩的某些元素。但事实证明，真正有效的感恩实践与之截然不同。神经影像数据、生理指标（如炎症标志物）研究，以及单纯考察心理效应和感恩实践长期/短期影响的研究，都指向一种完全不同的方法——通过感恩积极改善健康指标。有研究表明，每周进行两三次甚至仅一次感恩练习，就能对主观幸福感产生持久深远的影响。人们反馈称，仅仅通过增加感恩练习，就感到更快乐、更有意义、更愉悦，甚至对生活经历产生敬畏感。

I, I think like many of you would have thought that an effective gratitude practice simply involves writing down a few things or many things that we're grateful for, or thinking about those, or really making an effort to somaticize or feel some of the elements of gratitude while writing out that list or thinking about that list. It turns out that an effective gratitude practice doesn't resemble that at all. The neuroimaging data, the physiological data, looking at things like inflammatory markers, other studies purely looking at the psychology and the long and short term effects of an effective gratitude practice point to a completely different approach to using gratitude to positively impact health metrics. There are studies showing that performing a gratitude practice twice or three times, or even just once a week can lead to a pervasive, a long lasting impact on subjective well-being. People report feeling happier, more meaning, joy, even awe for their life experience, simply in response to adding a gratitude practice.

但感恩实践还有额外益处。研究表明，定期感恩能以两种方式增强对创伤的抵抗力：既能重构并强化对既往创伤的适应力——缓冲早期创伤带来的负面生理心理影响，也能从多方面预防未来可能遭遇的创伤。感恩实践的另一个作用是改善社会关系——而且不仅限于你表达感恩的那段关系。

But there are additional benefits of a gratitude practice. There are studies showing that a regular gratitude practice can provide resilience to trauma in two ways. It can provide a reframing and resilience to prior traumatic experiences. So buffering people against the negative physiological effects and psychological effects of earlier trauma, but also inoculating them in many ways to any traumas that might arrive later in life. The other thing that a gratitude practice does is it's been shown to benefit social relationships, but not just for the relationship in which you express gratitude, right?

表面上看，你可能会想：如果我反复对某人表达感恩，就会对那人产生更好感觉。这确实是感恩实践的一种效果（称为亲社会或人际感恩实践）。但近期多项发表在优质期刊的研究指出，定期感恩练习还能全面提升各类社会关系——职场、学校、家庭、恋爱关系，甚至与自我的关系（这才是主观幸福感的真正核心）。对于那些认为感恩实践'太虚浮'或'玄乎'的听众——比如需要把手放在心口去感受生活中美好事物（即便处境艰难）——我们要探讨的内容完全不是这样。

So on the face of it, you might think, okay, if I express gratitude for somebody over and over, over and over, over and over, then I'm going to feel better about that person. And indeed that is one effect of a gratitude practice that's called a pro social or inter social gratitude practice. But there are now several studies, recent studies in good journals pointing to the fact that a regular gratitude practice can also enhance one's social relationships across the board in the workplace, at school, with family, in romantic relationships, and even one's relationship to themselves, which is really what the subjective feelings of well-being are. And for those of you that are coming to this conversation thinking gratitude practice, oh, that's kind of wishy washy or woo, it's going to involve putting your hand on your heart and feeling into all the amazing things that you happen to have even when things are really terrible. That's not where we're going at all.

所以如果你认为感恩实践'太弱效'，请做好准备：数据表明感恩实践其实是一种极其强效的方法，能引导你的心理和生理健康向积极方向发展，且效果极为持久。在深入探讨感恩的工具、机制和科学研究前，我想先建立讨论框架。感恩是我们所称的'亲社会行为'或'亲社会心态'——任何能让我们在人际交往（包括与自我的互动）中更高效的行为或思维模式。

So if you are of the mindset that a gratitude practice is kind of weak sauce, buckle up because the data actually point to the fact that a gratitude practice is a very, very potent way in which you can steer your mental and physical health in positive directions. And that those effects are very long lasting. Before we dive into the tools and mechanisms and scientific studies around gratitude, I'd like to just set the framework for the discussion. Gratitude is what we call a pro social behavior or a pro social mindset. Pro social behaviors are basically any behavior or mode of thinking that allow us to be more effective in interactions with other people, including ourselves.

‘亲社会’不仅是这些工具、实践和心态的统称。大脑中确实存在专门负责亲社会思想和行为的神经回路。先不深入细节（稍后会讨论），我们大脑中存在所谓'趋近性'回路，其设计功能是让我们更接近事物，并更深入感知细节——无论是正在品尝的美食，

Now prosocial is not just a name that we give these different tools and practices and mindsets. They're actually neural circuits in the brain that are specifically wired for pro social thoughts and behaviors. So without getting into too much detail just yet, we will later, we have circuits in the brain that are what we call appetitive. They are designed to bring us closer to things and to bring us into closer relation to the details of that sensory experience. Now that could be a delicious food that you're eating.

与爱人互动，与朋友或任何你喜欢的人交流，甚至是你与自我的关系。当亲社会回路更活跃时，大脑中与回避/防御行为相关的神经回路实际上会受到抑制（即活性降低）。因此我想建立的框架是：大脑中存在类似跷跷板的神经回路系统——一组亲社会回路旨在让我们更接近他人（包括自我）和某些感官体验；

It could be interacting with a loved one. It could be interacting with a friend or anyone that you happen to like. It could even be in your relation to yourself. And the neural circuits in the brain that are associated with aversive or defensive behaviors are actually antagonized, meaning they are reduced when the pro social circuits are more active. So the framework here that I'd like to set is that we have this kind of seesaw of neural circuits in the brain, one set that are pro social and are designed to bring us closer to others, including ourselves, closer to certain sensory experiences, right?

因为许多亲社会行为也可以针对宠物、食物或任何我们想要更亲近并渴望更多的事物。而防御回路则涉及大脑区域，没错，包括与恐惧相关的区域，但也包括那些确实与僵直或退缩反应相关的大脑和身体区域。因此，理解感恩的关键在于它属于这类亲社会行为，旨在让我们更亲近各类事物，并提升我们从这些体验中获取细节的层次。今天讨论的核心是，感恩被证明是我们撬动思维最有力的支点之一。当你观察这两种回路间的身体生理反应时，还能为跷跷板上与积极亲社会感受相关的那一侧增添些许轻盈。

Because a lot of pro social behaviors can also be geared towards things like pets or food or anything that we find we want to be closer to and want more of. Whereas the defensive circuits involve areas of the brain, yes, such as areas that are involved in fear, but also areas of the brain and body that are literally associated with freezing or with backing up. So the way to think about gratitude is that falls under this category of pro social behaviors, which are designed to bring us closer to different types of things and to enhance the level of detail that we extract from those experiences. The key thing for today's discussion is that gratitude turns out to be one of the most potent wedges by which we can insert our thinking. And as you also see the physiology of our body between these two circuits and give a little more levity, if you will, to the side of the seesaw that's associated with positive pro social feelings.

如果你持续想象这个跷跷板画面，感恩练习真正美妙之处在于——即使不频繁但坚持重复进行时，人们实际上能重塑神经回路，使我所说的亲社会与防御行为间的跷跷板开始倾斜。这意味着我们现在可以确定，定期感恩练习能改变亲社会回路，使其主导我们的生理和心理状态，从而默认提升身心健康的多重维度。这样我们就不必总是刻意追求快乐。现在请允许我短暂插播感谢我们的赞助商Eight Sleep，他们生产的智能床罩具备制冷、加热和睡眠监测功能。

And if you keep imagining this seesaw imagery, what's really beautiful about gratitude practices is that if they're performed repeatedly and not even that often, but repeatedly, then one can actually shift their neural circuits such that the seesaw that I'm calling pro social versus defensive behaviors can actually start to tilt. What this means is that we now know with certainty that a regular gratitude practice can shift the prosocial circuit so that they dominate our physiology and our mindset in ways that can enhance many, many aspects of our physical and mental health by default. So we don't always have to constantly be in practice trying to be happy. I'd like to take a quick break and acknowledge our sponsor Eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating, and sleep tracking capacity.

确保优质睡眠的最佳方式之一是调控睡眠环境的温度。这是因为要进入并保持深度睡眠，体温需降低1-3度；而为了醒来时神清气爽，体温又需回升1-3度。Eight Sleep能根据个人需求整夜自动调节床温。我使用他们的床罩已超四年，睡眠质量得到彻底改善。

One of the best ways to ensure a great night's sleep is to make sure that the temperature of your sleeping environment is correct. And that's because in order to fall and stay deeply asleep, your body temperature actually has to drop by about one to three degrees. And in order to wake up feeling refreshed and energized, your body temperature actually has to increase by about one to three degrees. Eight Sleep automatically regulates the temperature of your bed throughout the night according to your unique needs. I've been sleeping on an Eight Sleep mattress cover for over four years now, and it has completely transformed and improved the quality of my sleep.

Eight Sleep刚推出新款Pod 5，具备多项重要新功能。其中'自动驾驶'模式是能学习睡眠规律的AI系统，可针对不同睡眠阶段调节环境温度。当检测到打鼾时会自动抬高头部，并通过其他调整优化睡眠。Pod 5底座还内置与App联动的扬声器，可播放助眠和恢复音频。

Eight Sleep has just launched their latest model, the Pod five, and the Pod five has several new important features. One of these new features is called autopilot. Autopilot is an AI engine that learns your sleep patterns to adjust the temperature of your sleeping environment across different sleep stages. It also elevates your head if you're snoring and it makes other shifts to optimize your sleep. The base on the Pod five also has an integrated speaker that syncs to the Eight Sleep app and can play audio to support relaxation and recovery.

音频库包含多个NSDR（非睡眠深度休息）引导语——这是我与Eight Sleep合作录制的。NSDR能缓解轻微睡眠不足的负面影响，并帮助半夜醒后重新入睡。这是人人首次使用就能受益的强大工具。访问eightsleep.com/huberman可享新款Pod 5最高350美元优惠，该产品支持全球多国配送（含墨西哥和阿联酋）。

The audio catalog includes several NSDR, non sleep deep rest scripts that I worked on with Eight Sleep to record. NSDR can help offset some of the negative effects of slight sleep deprivation and NSDR gets you better at falling back asleep should you wake up in the middle of the night. It's an extremely powerful tool that anyone can benefit from the first time and every time. If you'd like to try Eight Sleep, go to eightsleep.com/huberman to get up to 03:50 dollars off the new Pod five. Eight Sleep ships to many countries worldwide, including Mexico and The UAE.

重申优惠链接：eightsleep.com/huberman 最高立省350美元。现在我们来探讨感恩与亲社会行为相关的神经化学机制。本播客多次提及神经调质——对于不熟悉的听众，这是大脑和身体释放的能改变其他神经回路活性的化学物质，它们选择性增强或抑制特定脑区活动，包括多巴胺、血清素、乙酰胆碱、肾上腺素等。

Again, that's eightsleep.com/huberman to save up to $350 Now I'd like to talk about some of the neurochemistry and neural circuits associated with gratitude and pro social behaviors. Numerous times on this podcast, I've talked about so called neuromodulators. For those of you that might've forgotten or have never heard of neuromodulators before, neuromodulators are chemicals that are released in the brain and body that change the activity of other neural circuits. They make certain brain areas more likely to be active and other brain areas less likely to be active. These neuromodulators have names like dopamine, serotonin, acetylcholine, epinephrine, and so on.

与感恩及亲社会行为相关的主要神经调质是血清素。它由脑干中称为中缝核（Raphe）的少量神经元释放，这些神经元通过轴突将信号传递至大脑多处，通常会增强某些神经回路的活性——这些回路促使我们更倾向于接触特定体验。细想很合理：当某种化学物质在特定条件下触发神经回路活动，就会让你更愿意持续互动，甚至主动寻求与某人、某地或某物更深入的接触。

The main neuromodulators associated with gratitude and prosocial behaviors tends to be serotonin. Serotonin is released from a very small collection of neurons in the brainstem called the Raphae, R A P H E, the Raphae nucleus, and a few other places in the brain. And the Raphae neurons send these little wires that we call axons out to numerous places in the brain. And they tend to increase the activity of particular neural circuits that lend themselves to more approach to particular types of experiences. That makes total sense if you think about it, have a chemical that under certain circumstances released in the brain that triggers the activity of neural circuits that makes the organism you more likely to stay in an interaction with something or even lean in and seek a more detailed interaction with that person, place, or thing.

这些血清素系统会激活两个主要脑区。当人们经历让他们感到感激的事情时，激活程度会随着感激情绪的强烈程度而变化。这两个区域有特定名称——前扣带皮层和内侧前额叶皮层——它们与大脑中许多其他网络相连。

And two main brain areas are activated by these serotonergic systems. And when people experience something that makes them feel gratitude and the amount of activation scales with how intensely the person experienced the feeling of gratitude. And those two areas have particular names. You don't need to know the names, but for those of you that want to know, they are the anterior cingulate cortex and the medial prefrontal cortex. And of course these brain areas are connected to a number of other networks in the brain.

事实上，正是通过这些区域的活动，特定的思维过程会被触发，比如'我想体验更多'或'这感觉真好'。然后神经元会直接作用于肌肉，让你愿意保持静止（如果喜欢当前体验）或靠近吸引你的事物。内侧前额叶皮层涉及规划、深度思考及对过去/现在/未来经历的评估，因此能参与多种活动。

In fact, that's how they get you or others to lean into certain experiences because when these areas are active, certain thought processes get invoked. Those thought processes probably resemble something like, I'd like to experience more of this, or this feels really good. And then they literally feed onto your muscles via the neurons, making you happy to stay stationary if you're experiencing something you like, or to move closer to something that you find attractive to you, literally. Many of you have probably heard of the medial prefrontal cortex, because this is the area of the brain that is involved in planning and in deep thinking and evaluation of different types of experiences, past, present, or future. And the reason it can be involved in so many different things.

它对感恩特别重要是因为能设定情境——字面意义上定义你体验的含义。其工作原理是：大脑深处有许多神经回路仅产生某些感觉（或让你感知这些感觉）。

And the reason it's especially important for gratitude is that medial prefrontal cortex sets context, okay? It sets context and it literally defines the meaning of your experience. How is it that medial prefrontal cortex sets the context of everything in your life? Well, it does it the following way. You have a number of circuits deeper in your brain that simply create some sensations, or they allow you, I should say, to perceive certain sensations.

以冷水浴为例：即便适应低温，不适感不可避免。但若你主动选择（知道有健康益处），内侧前额叶皮层就能控制下丘脑等区域，正向影响释放的神经化学物质。自主选择产生的多巴胺和抗炎指标等效果，远优于被迫进行的情况。

Let's use the example of cold exposure, something that we'd sometimes talk about in this podcast for other reasons. If you were to deliberately place yourself into an ice bath, it would be uncomfortable. Even if you're adapted to cold and so forth, the discomfort is non negotiable. However, if you are doing it because you want to, or because you have knowledge that there are particular health benefits, the medial prefrontal cortex can then control areas of your deeper brain like the hypothalamus to positively impact the neurochemicals that are released into your system. Your knowledge that you are making the choice that it's you that's deciding to put yourself through this discomfort has been shown to create a very different and positive effect on things like dopamine, on things like anti inflammatory markers in your immune system, etcetera, compared to if someone pushes you into an ice bath, or if you are doing it because someone insists that you do it and you really, really don't want to.

关键在于动机差异：自愿与被迫。比如老鼠自愿跑轮会降压改善神经化学，但若被迫同步跑轮（因装置联动），健康指标就会恶化——血压和应激激素上升。

So there's a very subtle distinction here. It's just the distinction of motivation and desire or lack of motivation and being forced into something. If you take a mouse for instance, and it runs on a running wheel, which mice really like to do, there are many positive effects on reducing blood pressure, improvements in neurochemistry, etcetera, in that mouse. However, if there's a mouse in the cage right next to it, that's trapped in the running wheel and it has to run every time the other mouse runs because the wheels are linked, well then the second mouse that's forced to do the exact same running experiences negative shifts in their overall health metrics. Blood pressure goes up, stress hormones go up, etcetera, because it's not actually making the choice.

内侧前额叶皮层如同调节旋钮：能将相同体验框定为有益（产生健康增益）或有害（被迫进行时）。其神经元通过调整原始反射神经回路的活动来实现这点——为机械反应赋予情境意义。感恩心态正通过激活前额叶皮层来设定体验情境，从而获得健康效益。

Medial prefrontal cortex is the knob or the switch rather that can take one experience and allow us to frame it such that it creates positive health effects and the exact same experience framed as something we don't want to do or that we are forced to do can create negative health effects. Now, how exactly the neurons in medial prefrontal cortex do that is rather complicated and frankly not completely understood, but it's somehow able to adjust the activity of other neural circuits that are purely reflexive. As we say in neuroscience, like really dumb neural circuits that are just like switches and place a context onto it. So gratitude is a mindset that activates prefrontal cortex and in doing so sets the context of your experience such that you can derive tremendous health benefits, which leads us to the question, what kind of gratitude practice is going to accomplish this? You can't simply lie to yourself.

但你不能自欺欺人——并非所有经历都能强行美化成'学习机会'。身体不会对虚假的积极暗示作出正向反应。这种谬误在自我提升领域相当普遍。

You can't simply say, oh, well, every experience is a learning experience or a terrible thing happens, oh, good. I'm just going to say good. And that your body will react as if it's good for you. That's a myth. And frankly, it's a myth that's fairly pervasive in the self help and self actualization literature.

我们不能简单地自欺欺人或假装成功直到真正成功。神经回路非常强大且具有高度可塑性，它可以根据情境调整，但并不愚钝。当你欺骗自己某个经历是否真正有益时，你的大脑心知肚明。那么，有效的感恩练习应该是什么样的呢？

We can't simply lie to ourselves or fake it until we make it. Neural circuitry is very powerful and very plastic. It can be modified and it's very context dependent, but it's not stupid. And when you lie to yourself about whether or not an experience is actually good for you or not, your brain knows. So what does an effective gratitude practice look like?

让我们先看看什么是无效、糟糕的感恩练习，因为这其中蕴含了关键信息——包括我自己和数百万人都做错了的事实。网上常见的感恩练习，或是人们在各种演讲中提到的，通常包括写下、复述或思考五到二十件你特别感激的事，然后努力感受其中一些，深入体会与这些人、地点和事物相关的情感和感知。但多数研究表明，这类感恩练习对改变你的神经回路、神经化学或身体机能效果有限——要知道你的器官与神经回路相连，大脑和身体的回路本应激活前额叶皮层及亲社会神经网络。实际上，最有效的感恩练习不是给予或表达感恩，而是接收感恩。

Well, let's examine what an ineffective, what a poor gratitude practice looks like because therein lies some really important information, including the fact that I, and I think millions of other people out there are doing it wrong. Most gratitude practices that you see online and that people talk about in various talks and so forth involves something like writing down or reciting or thinking about five or 10 or three or 20 things that you're especially grateful for. And then really trying to feel into some of those really try and think deeply about the emotions, the sensations, the perceptions that are associated with those particular people, places, and things on your list. Most studies actually point to the fact that that style of gratitude practice is not particularly effective in shifting your neural circuitry, your neurochemistry, or your somatic circuitry, the circuits in your body, because you literally have organs and neural circuits that are connected, the circuits of your brain and body toward enhanced activation of prefrontal cortex, enhanced activation of these pro social neural networks that we were talking about earlier. It turns out that the most potent form of gratitude practice is not a gratitude practice where you give gratitude or express gratitude, but rather where you receive gratitude, where you receive thanks.

这个发现让我非常惊讶。现有大量相关研究，其中一项特别有趣：当同事面对面朗读感谢信时前额叶的激活——一项近红外光谱（NIRS）研究。我会解释这些术语的含义，你们现在已经知道前额叶激活指什么了。

And this to me was very surprising. There are a number of studies about this now. One in particular that I think is interesting is called prefrontal activation while listening to a letter of gratitude read aloud by a coworker face to face, a NIRS study, NIRS. I'll explain what all this means. You now know what the prefrontal activation part is.

这指的是前额叶皮层的激活。NIRS研究只是个技术术语。实验中，研究人员让同事匿名撰写感谢信给另一位同事，然后让双方当面朗读聆听，同时扫描大脑活动。结果显示，接收感谢时前额叶网络的强烈激活表明：相比表达感恩，接受感谢能产生更显著的积极神经变化。

This is activation of the prefrontal cortex. The NIRS, NIRS study, that's just a technical term. So in this particular experiment, what they did is they had coworkers write a letter of gratitude of thanks to another coworker unbeknownst to the other coworker. And then they sat down together and then they imaged brain activity as this letter was being read and as the letter was being heard, received. And it showed very robust effects on these prefrontal networks that pointed to the fact that receiving gratitude is actually much more potent in terms of the positive shifts that it can create than giving gratitude.

对于想体验感恩益处的人，干坐着等待别人送来感谢信并不现实。如何自主创造接收感恩的体验以获得研究中的效果呢？这就要提到安东尼奥·达马西奥的重要研究——他通过探索感恩的神经关联，定义了前额叶皮层等与亲社会行为相关的脑区。他们的实验设计很巧妙：不是让受试者表达感恩，而是让他们在脑部扫描仪中观看他人经历人生积极事件的故事。

For many people who want to experience the positive effects of gratitude, it's probably not the most advantageous approach to just sit around waiting, hoping that someone's going to deliver all these letters or words of gratitude. How is it that you can create that sense of receiving gratitude for yourself and thereby derive the effects of gratitude as outlined in this particular study? And there we go to the important work of the great Antonio Damasio, who explored these neural correlates of gratitude to define the areas of the brain that are associated with prosocial behaviors like the prefrontal cortex. What they did was interesting rather than have people express gratitude, they had the subjects go into the scanner. So their brains are being imaged and they watched narratives, stories about other people experiencing positive things in their life.

这些是极具冲击力的故事——关于种族灭绝幸存者的经历。受试者本身并非幸存者，他们观看的视频中，幸存者讲述了在他人帮助下渡过心理和生理生存危机的历程。

And in this case, these were powerful stories. These were stories about survivors of genocide. So that's what they're watching. The subjects were subjects that were not survivors of genocide. So they were watching these videotapes of people that had survived genocide and had people help them along the way as part of their story of survival, either psychological and or obviously they survived long enough to make the video or physical survival.

这些故事传递了大量挣扎经历。幸存者们描述所处绝境的同时，也提及那些微小却改变命运的关键细节。例如研究论文中记载：一名患病数周的妇女，被同为囚犯的医生偶然找到药物（未说明具体方式）而获救——这类故事展现了感恩的深刻来源。

So within these stories, was a conveyance of a lot of struggle. These people talked about the horrible situations they were in, but also small, but highly significant features of their history that had led to their own feelings of gratitude. So for instance, it says a woman at the image, this is literally from the scientific paper, somebody had been sick for weeks. So the woman's describing how she'd been sick for weeks, and then another prisoner who was a doctor finds a particular medicine somehow, it doesn't describe how, and literally saves her life. So these sorts of stories.

现在，仅仅在科学论文和讨论的背景下听到这些，可能影响不大。这项研究真正重要之处，也是我们所有人都需要知道的是，那些关于他人获得改变人生际遇的力量的故事，都深植于叙事之中。而人类大脑尤其倾向于故事。从幼年到老年，我们拥有喜欢将过去、现在、未来串联起来的神经回路，其中包含不同角色、主角与反派。故事是我们大脑组织信息的主要方式之一。

Now, just hearing this in the context of nothing but a scientific paper and discussion, these probably aren't that impactful. What's really important about this study and is really important for all of us to know is that these stories of other people receiving things that were powerful for them in their life trajectory is embedded in story. And the human brain especially is so oriented towards story. We have neural circuits that like to link together past, present, future, have different characters, protagonists and antagonists from the time we're very young until the time we're very old. Story is one of the major ways that we organize information in the brain.

大脑中似乎确实存在讲述故事和聆听故事的神经回路。因此，重要的不仅仅是这些人从种族灭绝中幸存下来——这固然重要且美好——更在于他们获得帮助的描述被嵌入了一个更宏大的叙事中。这项科学研究的受试者观看这些震撼故事时，当他们开始与讲述者产生情感共鸣，与社会亲善行为和感恩相关的神经回路就会强烈激活。

Does seem to be storytelling and story listening circuits in the brain. So what's important is not simply that these people survived genocide. That's obviously important and wonderful, but it's not just that they were helped along the way. It's that the description of their help is embedded in a larger story. So the human subject is in this scientific study is watching these powerful stories and the neural circuits associated with prosocial behaviors and with gratitude become robustly active when they start to feel some affiliation with the person telling the story.

如果你回想早前那个关于'接受感恩是激活这些感恩回路最有效方式'的研究，就会发现本研究的受试者其实也在接收感恩感——只不过是通过其他受试者的叙事传递的，这让我着迷。我原以为最好的感恩练习就是坐下来列出所有感激之事，这逻辑看似合理。但事实证明这些神经回路并非如此运作——要真正激活感恩回路、血清素系统（可能还包括催产素系统）及前额叶网络，必须强烈代入'接受帮助'的概念。我们早就知道改善睡眠的方法，包括服用苏糖酸镁、茶氨酸、洋甘菊提取物和甘氨酸等成分，以及藏红花和缬草根等较冷门的物质——这些都是经临床验证能助你入睡、保持睡眠并神清气爽醒来的成分。

So if you think about the earlier study that receiving gratitude is the most powerful way to activate these circuits for gratitude, The subjects in this study in many ways are receiving a sense of gratitude, but through the narrative of one of these other subjects, which I find fascinating, I would have thought a great gratitude practice would be sit down, list out all the things you're grateful for. That just seems so logical to me, but it turns out that these neural circuits don't work that way, that to really activate these circuits for gratitude and the serotonin and probably the oxytocin system as well, and its prefrontal networks, one has to powerfully associate with the idea of receiving help. We've known for a long time that there are things that we can do to improve our sleep. And that includes things that we can take things like magnesium threonate, theanine, chamomile extract, and glycine, along with lesser known things like saffron and valerian root. These are all clinically supported ingredients that can help you fall asleep, stay asleep, and wake up feeling more refreshed.

我很兴奋地宣布，我们的长期赞助商AG1刚刚推出了新产品AGZ——一种夜间饮品，旨在改善睡眠质量，让你醒来时倍感清爽。过去几年我协助AG1团队研发了这个新配方，它以精准比例汇集了最佳助眠成分，只需简单冲泡即可饮用。这省去了在众多助眠补充剂中筛选合适剂量和成分的复杂过程。据我所知，AGZ是市面上最全面的睡眠补充剂。

I'm excited to share that our longtime sponsor AG1 just created a new product called AGZ, a nightly drink designed to help you get better sleep and have you wake up feeling super refreshed. Over the past few years, I've worked with the team at AG1 to help create this new AGZ formula. It has the best sleep supporting compounds in exactly the right ratios in one easy to drink mix. This removes all the complexity of trying to forge the vast landscape of supplements focused on sleep and figuring out the right dosages and which ones to take for you. AGZ is to my knowledge, the most comprehensive sleep supplement on the market.

我在睡前30-60分钟服用它（顺便说一句味道很棒），这显著提升了我的睡眠质量和深度——无论是主观感受还是睡眠监测数据都证明了这点。期待大家都能尝试这个AGZ新配方，享受优质睡眠带来的益处。

I take it thirty to sixty minutes before sleep. It's delicious by the way. And it dramatically increases both the quality and the depth of my sleep. I know that both from my subjective experience of my sleep and because I track my sleep. I'm excited for everyone to try this new AGZ formulation and to enjoy the benefits of better sleep.

AGZ有巧克力、薄荷巧克力和混合莓果三种口味，正如我之前所说都非常美味。三者中我最爱薄荷巧克力，但其实每种都喜欢。若想尝试AGZ，请访问drinkagz.com/huberman获取专属优惠，再次强调是drinkagz.com/huberman。

AGZ is available in chocolate, chocolate mint, and mixed berry flavors. And as I mentioned before, they're all extremely delicious. My favorite of the three has to be, I think chocolate mint, but I really like them all. If you'd like to try AGZ, go to drinkagz.com/huberman to get a special offer. Again, that's drinkagz.com/huberman.

现在让我们花点时间思考如何构建终极感恩练习——即最有效的感恩实践方式，因为正确的感恩练习能产生诸多积极影响。显然接受感恩力量强大，但被动等待他人感恩并不现实。可以确定的是，我们必须真实体验他人的经历，而最佳方式就是通过故事。因此在设计有效感恩练习时，我认为寻找能触动你的他人叙事非常值得。

So let's just take a moment and start to think about how we are going to build out the ultimate gratitude practice, meaning the most effective gratitude practice for us to do because of all the many positive effects that an effective gratitude practice can have if it's the proper one. It's very clear that receiving gratitude is powerful, but it's also very clear that waiting around to receive that gratitude is an impractical approach. What we know for sure is that there has to be a real experience of somebody else's experience. And that the best way to do that is story. So in thinking about how to build out an effective gratitude practice, it's very worthwhile, I believe to find someone's narrative that's powerful for you.

从多个角度思考这个问题，关键在于这个故事必须能激励你，因为——用一个不太精确的说法——它展现了人类精神之美或人类互助的能力。我发现这非常了不起，因为这实际上意味着感恩的神经回路让我们能够交换感激之情。我们可以真正观察到他人获得帮助或给予帮助的过程。这种对我们同类互助行为的观察，能让我们体验到一种真实的化学和神经回路激活带来的提升感，这与简单写下你感激的事物截然不同，对吧？

In many ways to think about this is it's got to be a story that inspires you because of the, for lack of a better phrase, the beauty of the human spirit or the ability of humans to help other humans. And I find this remarkable because what this really means is that the circuits for gratitude are such that we can exchange gratitude. We can actually observe someone else getting help, someone else giving help. And that observation of our species doing that for one another allows us to experience the feeling of a genuine chemical and neural circuit activation lift, you will. Very, very different than simply writing out the things that you're thankful for, right?

那么具体该如何操作呢？人们消化故事的方式多种多样——看电影、听播客、阅读书籍。世界上有无数故事可供选择。显然，有效的感恩练习需要定期重复进行。

And so how would you do this? Well, people digest story in a number of different ways. People watch movies, people listen to podcasts, people read books. There are a tremendous number of stories out there. It's clear that an effective gratitude practice has to be repeated from time to time.

因此，我不建议制定一个需要你不断搜寻励志故事的方案。最有效的工具应该是：要么深入思考（你也可以写下来）当别人对你所做之事表达感谢时你的感受；要么深刻想象/思考他人获得帮助时的情感体验。我要强调，你选择的故事不必与你的生活经历有任何相似之处，关键在于它能触动你。具体做法就是找到一个对你特别有意义的故事。

So what I would not suggest is that we build a protocol in which you're constantly forging for inspirational stories over and over again. Rather the most effective protocol or tool is going to be either to think into, and you could write this out if you like, but think into when somebody was thankful for something that you did and really start to think about how you felt in receiving that gratitude or, and or I should say, imagining or thinking about deeply the emotional experience of somebody else receiving help. I want to emphasize that the story that you select does not have to have any semblance to your own life experience. It's just about what happens to move you. And so the way that one could do this is to find a story that's particularly meaningful for you.

然后只需做些简短笔记，用要点形式列出：困境是什么、帮助是什么、以及它如何触动你的情绪。你记下这些故事要点作为提醒，之后朗读并沉浸体验那种获得感激的丰富感受。这个过程实际上只需1-3分钟，并不是个冗长的练习。

And then to just take some short notes, bullet point notes, just list out for instance, what the struggle was, what the help was and something about how that impacts you emotionally. You've written down a few notes about what that story is just to remind you. And then you read those out and you think into the richness of that experience, that receiving of gratitude. Now this could be done literally for one minute or two minutes or three minutes. This is not an extensively long practice.

如果你有过接受感激的亲身经历或某个特别打动你的故事，它就会成为通往感恩网络的捷径——这些亲社会网络一旦激活几乎瞬间就能响应，这与许多其他练习大不相同。这种基于叙事的感恩练习还有个显著好处：故事对我们生理状态的影响。这意味着你可以反复使用同一个故事（哪怕是简化版要点），这将在你的心跳和呼吸上产生真实可察的变化。

Now, if you have an experience of receiving gratitude or a story that's very potent for you, it becomes a sort of shortcut into the gratitude network, these prosocial networks, meaning the activation of these circuits becomes almost instantaneous. And that's very different than a lot of other practices out there. Now there's another very clear and positive effect of using this narrative or story based approach to a gratitude practice. And that's what story does for our physiology. What this means for your gratitude practice is that having a story that you can return to over and over again, even if it's not the entire story, you're just using the shorthand bullet point version of your story will create a perceptible and real shift in your heartbeat and in your breathing.

事实上已有大量研究表明，有效的感恩练习不仅能快速激活大脑中亲社会行为的神经回路，还能激活心脏、肺部及其他器官的特定回路，使你每次都能进入可复现的感恩状态。关键是要反复使用同一个故事（无论是亲身经历还是他人故事），这使它成为极具效力的工具——甚至60秒的练习就能带来巨大收益。之前我说过你无法欺骗自己说'我讨厌这个东西但我很感激'，《科学报告》期刊发表过一项有趣研究...

And actually that's been demonstrated over and over now that an effective gratitude practice is one that can rapidly shift not just the activation of these circuits in your brain for prosocial behaviors, but also activation of particular circuits in your heart and in your lungs and the other organs of your body, such that you can get into a reproducible state of gratitude each time. The key thing is that you want to use the same story, even if it's your own experience or somebody else's and keep coming back to it over and over again. That makes it a very potent tool that you can get a tremendous amount of benefit from with even as short as sixty seconds of practice. Earlier, I talked about how you can't lie to yourself and say, you know, I'm so grateful for this thing that I actually hate. There's a really interesting studies published in Scientific Reports, which is a nature research journal.

论文标题是《意图与利益评估的神经反应是区分感恩与快乐的关键》。这个研究比较复杂，我重点讲几个发现：研究者使用功能磁共振成像技术高精度观测大脑回路激活，实验中让人们在不同情境下接收金钱。

The title of it is neural responses to intention and benefit appraisal are critical in distinguishing gratitude and joy. It's a somewhat complicated study. So I'm just going to hit on some of the high points, but basically what they did is they use functional magnetic resonance imaging. So they could look at brain circuitry activation with very high precision. And they had people receiving money in the context of this experiment.

他们能够辨别所收到的钱是出于真心还是勉强给予。他们观察感恩之情是否随金额或赠予者的意图而变化——赠予者是真心实意还是迫于无奈。值得注意的是，虽然金额大小确实显著影响受赠者的感恩感受（这很合理，因为金额是衡量感谢程度的标准之一），但更具影响力的变量在于赠予者是否怀着真诚而非勉强的意图。这揭示了超越感恩实践的深刻启示：唯有真挚的感谢才真正重要。

And they had some knowledge as to whether or not the money that they were receiving was given to them wholeheartedly or reluctantly. They looked at whether or not the sense of gratitude scaled with the amount of money received and or the intention of the benefactor, whether or not the person giving the money was doing it wholeheartedly or reluctantly. And what's remarkable is that while the amount of money given was a strong component in whether or not somebody felt that they had received gratitude, which makes sense, the amount of money is some metric of whether or not somebody feels thanked. The stronger variable, the bigger impact came from whether or not the person giving the money was giving it with a wholehearted intention and not a reluctant intention. This tells us many things that extend way beyond gratitude practices, which is that genuine thanks are what count.

因此这在一定程度上约束了我们的感恩实践，但我觉得这种约束既有趣又关键——你不能自我欺骗说'因为收到很多钱，所以体验很棒'，即便明知对方给得不情不愿，或是'老板讨厌我却给我加薪'。这提醒我们作为给予者：若非真心实意，我们就会削弱对方可能获得的感恩感受。现在请允许我短暂插播感谢赞助商Our Place——他们生产我最钟爱的锅具与厨具。

So this constrains our gratitude practices somewhat, but I think in an interesting and important way, you can't tell yourself that an experience was great or that, you know, I got a lot of money and therefore it justified it. Even though, you know, I think that they gave it to me reluctantly or my boss hates me, but they gave me a raise. And that tells us that if we are the giver, that we better be giving wholeheartedly or we are undermining the sense of gratitude that someone is going to receive from us. I'd like to take a quick break and acknowledge our sponsor, Our Place. Our Place makes my favorite pots, pans, and other cookware.

令人震惊的是，80%的不粘锅、厨具及各类厨房用品中仍含有PFAS等永久性有毒化合物。正如我在往期播客所述，这类特氟龙等'永久化学物'与激素紊乱、肠道菌群破坏、生育问题等重大健康风险相关。因此避免接触至关重要，这也是我极力推荐Our Place的原因——他们的产品采用最高品质原料，完全不含PFAS等有毒物质。

Surprisingly toxic compounds such as PFAS or forever chemicals are still found in 80% of nonstick pans, as well as utensils, appliances, and countless other kitchen products. As I've discussed before in this podcast, these PFAS or forever chemicals like Teflon have been linked to major health issues such as hormone disruption, gut microbiome disruption, fertility issues, and many other health problems. So it's really important to try and avoid them. This is why I'm a huge fan of Our Place. Our Place products are made with the highest quality materials and are all completely PFAS and toxin free.

我尤其钟爱他们的钛金Always Pan Pro，这是首款零化学涂层的不粘锅，采用纯钛材质打造。这意味着它既不含永久性有害物质，也不会随时间降解或丧失不粘性，外观更是赏心悦目。

I especially love their titanium Always Pan Pro. It's the first nonstick pan made with zero chemicals and zero coating. Instead it uses pure titanium. This means it has no harmful forever chemicals and does not degrade or lose its nonstick effect over time. It's also beautiful to look at.

Our Place现已推出全线钛金专业厨具，运用革命性钛金不粘技术。若您需要无毒耐用的锅具，请访问fromourplace.com/huberman并使用优惠码Huberman。凭借100天无风险试用、免运费与免费退换服务，您可以零风险体验为何超百万人选择Our Place厨具。基于现有科学文献，我们正逐步构建终极感恩实践体系——我知道很多人渴望建立能对神经回路产生持久甚至永久积极影响的感恩练习。

Our place now has a full line of titanium pro cookware that uses its first of its kind titanium nonstick technology. So if you're looking for non toxic long lasting pots and pans, go to fromourplace.com/huberman and use the code Huberman at checkout. With a hundred day risk free trial, free shipping and free returns, you can try Our Place with zero risk and see why more than 1,000,000 people have made the switch to Our Place Kitchenware. So we are gradually building up the ultimate gratitude practice based on the variety of scientific literature that's out there. And I know that many people are probably interested in developing a gratitude practice that has long lasting, maybe even permanent positive effects on their neural circuitry.

鉴于此，我想介绍一项引人入胜的研究《感恩冥想对神经网络功能连接与心脑耦合的影响》。简而言之，反复的感恩练习会改变大脑回路的工作方式，并重塑心脏与大脑的互动模式。众所周知大脑控制心脏——当你因心理压力而心跳加速时就能体会到这点。

So with that in mind, I want to turn our attention to a really interesting study. It's entitled Effects of Gratitude Meditation on Neural Network Functional Connectivity and Brain Heart Coupling. And to make a long story short and a lot simpler than that title, repeated gratitude practice changes the way that your brain circuits work. And it also changes the way in which your heart and your brain interact. You're familiar with the fact that your brain controls your heart because you could be stressed about something that's perceived with your brain and then your heart rate will speed up.

你可能也注意到，当心率莫名加快时，大脑会立即追问原因。这正是因为心脑之间存在双向神经支配——它们通过双向通路持续对话。该研究发现，感恩练习能改变大脑内部及心脑之间的功能连接状态。最核心的结论是：持续的感恩实践可以重塑与情绪、动机相关脑区的静息态功能连接。

You're probably also familiar with the fact that if your heart rate speeds up for some reason or no reason, you're probably thinking, well, what's making my heart rate speed up? And that's because the brain and the heart are reciprocally innervated as we say, they're talking to one another in both directions. It's a two way highway. This study looked at changes in so called functional connectivity within the brain and between the brain and the heart in response to gratitude practices. To make a long story short, what they found is that a repeated gratitude practice could change the resting state functional connectivity in emotion and motivation related brain regions.

如果至今我还没提到坚持感恩练习的足够动力，那么这个研究绝对值得关注。因为他们发现定期感恩练习能重塑情绪通路的连接方式——不仅会降低焦虑恐惧回路的活跃度，还能显著增强幸福感回路以及动机回路的活性。我认为这非常了不起且重要，因为许多人都在与动力不足斗争，而很多高动机人群也常受焦虑恐惧困扰。这项研究实际上揭示了一箭双雕的效果。

If I haven't mentioned a strong enough incentive for doing a regular gratitude practice until now, this is definitely the one to pay attention to. Because what they found was a regular gratitude practice could shift the functional connectivity of emotion pathways in ways that made anxiety and fear circuits less likely to be active and circuits for feelings of well-being, but also motivation to be much more active. I find that remarkable and important because a number of people struggle with issues of motivation. A lot of people who are highly motivated also have issues with anxiety and fear. And so this study really points to the fact that it's a twofer.

当你建立良好的感恩习惯并定期实践时，既能抑制恐惧焦虑回路，又能提升积极情绪回路的效能，同时与动机和追求相关的神经回路也会得到加强。目前我们主要讨论了感恩对神经回路活性的影响，以及身体层面如心率呼吸等的一些变化，但尚未深入探讨健康指标的变化，比如炎症反应或免疫功能的改善等。接下来我将介绍2021年发表在《脑行为与免疫》期刊的一项精彩研究。

If you have a good gratitude practice and you repeat it regularly, you reduce the fear anxiety circuits, you increase the efficacy of the positive emotion, feel good circuits and the circuits associated with motivation and pursuit are actually enhanced as well. Thus far, we've mainly talked about the effects of gratitude on neural circuit activation and changes a little bit about some of the changes that are happening in terms of the body, heart rate and breathing and so forth. But we haven't talked a lot yet about the changes in health metrics, in things like inflammation or reductions in inflammation and immunity and things of that sort. So with that in mind, I'd like to describe the results of a really interesting recent study that was published in the journal Brain Behavior and Immunity. This was published 2021.

研究标题为《随机对照试验中感恩对健康益处的神经机制探索》，第一作者是Hazlett。该论文表明，持续进行我们讨论的这种感恩练习的女性，其大脑威胁检测中枢——恐惧网络核心组成部分杏仁核的活性会降低，同时显著减少TNF-α和白细胞介素6（IL-6）的生成。若你听过我关于免疫系统激活的那期节目，应该对TNF-α和IL-6有所了解。

The title of the study is Exploring Neural Mechanisms of the Health Benefits of Gratitude in A Randomized Controlled Trial. The first author is Hazlett. And basically what this paper showed was that women who had a regular gratitude practice of the sort that we've been talking about up until now showed reductions in amygdala activity, a brain area associated with threat detection, a intimate part of the fear network in the brain. So reductions in amygdala activation and large reductions in the production of something called TNF and IL-six interleukin six. Now, if you happen to have listened to the episode that I did on activating your immune system and immune function, you heard about TNF alpha and IL-six.

TNF-α和IL-6是促炎细胞因子，当机体受损或处于系统应激状态时会由细胞释放。短期来看它们有益，能召唤伤口愈合和细胞修复信号。但长期过高水平的TNF-α和IL-6则有害无益。

TNF alpha and IL-six are inflammatory cytokines. These are chemicals that exist in your body and that are released from cells when there is damage or kind of a systemic stress when your system is in duress. And in the short term, they can be beneficial. They can call in signals for wound healing and repair of cells, etcetera. But you don't want TNF alpha and IL-six levels to be too high and you don't want those levels to be up for too long.

这项研究的精妙之处在于，它证实感恩练习能显著降低TNF-α和IL-6水平。另一个有趣发现是：杏仁核活性下降与炎症因子减少的效应几乎在感恩练习完成后即刻显现。虽然研究对象仅为女性，但考虑到杏仁核的神经生物学机制以及TNF-α/IL-6在两性中都起促炎作用，我认为该结论同样适用于男性。现在我想强调最有效的感恩练习（至少据我所知）的关键要素。

And so this study is really nice because they showed significant effects in reducing TNF alpha and IL-six in response to a gratitude practice. And another interesting aspect of this study is that the reductions in amygdala activation and the reductions in TNF alpha and IL-six were very rapid. They occurred almost immediately after the gratitude practice was completed. And even though that study was performed exclusively on female subjects based on the biology and circuitry of the amygdala and the biology of TNF alpha and IL-six performing this inflammatory role in both men and women, I don't see any reason why the results of that study wouldn't pertain to both men and women. I'd like to just highlight the key elements of the most effective, at least to my knowledge, gratitude practice.

首先，练习必须基于具体叙事（即故事）。每次练习时无需复述整个故事，但需清楚故事内容及其与感恩实践的关联。其次，故事可以是接受真诚感谢的经历——关键要素在于你是被感谢方，且对方是真心实意表达感激；也可以是目睹他人接受或表达感谢的场景。

First of all, that practice has to be grounded in a narrative, meaning a story. You don't have to recite or hear that story every single time you do the gratitude practice, but you have to know what that story was and what the gratitude practice references back to. Second of all, that story can be one of you receiving genuine thanks. And the key elements there are that you are the one receiving the thanks, the gratitude, and that it's being given to you genuinely, wholeheartedly. Or it can be a story of you observing someone else receiving thanks or expressing thanks.

这种互动必须真实存在于给予者与接受者之间。确立感恩故事后，我建议用3-4个要点简记故事核心：包括接受感恩前你/对方的状态、接受感恩后的状态，以及其他赋予故事情感张力的元素。这些要点能快速唤起完整故事记忆，无需每次完整复述。

And that has to be a genuine interaction as well, both between the giver and the receiver. So those are the first three elements. What I recommend would be after you've established the story that you want to use for your gratitude practice, that you write down three or four simple bullet points that can serve as salient reminders of that story for you. It will serve as kind of a cue for that story without having to listen to or talk out the entire story. I would recommend writing down something about the state that you or the other person were in before they received the gratitude, the state that you were in or that the person was in after they received the gratitude and any other elements that lend some sort of emotional weight or tone to the story.

这段内容可以长达三页，也可以简化为几个要点。我认为这并不重要，关键在于它能深植于你的记忆中，并与这种真诚的感恩交流紧密相连。我认为这些才是关键要素。然后它就变得非常简单了。

This could be three pages of text if you like, or it could just be a couple of bullet points. I don't think it really matters. The important thing is that it's embedded in your memory and that it's really associated with this genuine exchange of thanks and the receivable of thanks. I think those are the key elements. And then it's very simple.

整个练习包括读出这些要点，作为对你神经系统的一种感恩暗示。然后大约一分钟——如果你仔细想想，这其实是微不足道的时间——或者两分钟，如果你更有雄心，最多五分钟，真正沉浸于那种接受过感恩或目睹他人接受感恩的真实体验中。如果我们退一步看这个方案，并将其与文献中常见的做法相比较——比如列出你感恩的所有事物、在心中默念你感恩的一切、细数你的福气——我认为每个人都应该时刻数算自己的福气。总有些事情值得感恩。

The entire practice involves reading off these bullet points as a cue to your nervous system of this sense of gratitude. And then for about one minute, which is a trivial amount of time, if you really think about it, or maybe two minutes, or if you're really ambitious up to five minutes of just really feeling into that genuine experience of having received gratitude or observed someone else receiving gratitude. So if we just take a step back from this protocol and compare it to what's typically out there in the literature, which is, make a list of all the things you're thankful for, recite in your mind all the things you're thankful for, count your blessings. So I think everybody should be counting their blessings all the time. There's always something to be thankful for.

但就一个科学基础扎实的感恩练习而言，它已被科学证明能在免疫系统和神经回路层面改变你的生理状态，减轻焦虑，增强动力，这些都是我们许多人一直追求的美好目标。我认为感恩练习展现出了其作为一项极其强大工具的潜力。感谢你们今天花时间关注并学习感恩科学。最后但同样重要的是，感谢你们对科学的兴趣。

But in terms of a scientifically grounded gratitude practice that is also scientifically demonstrated to shift your physiology at the level of your immune system and your neural circuitry, reducing anxiety, increasing motivation, all these wonderful things that so many of us are chasing all the time as goals. I think a gratitude practice reveals itself to be an immensely powerful tool. Thank you for your time and attention today, learning about the science of gratitude. And last but certainly not least, thank you for your interest in science.