Hooked: Building Habit-Forming Products

1. Introduction: Hi, my name is Nir Eyal and I'm the author of a book called Hooked, How to Build Habit-Forming Products. Today we're going to be talking about how to build habits inside your products and services, so that people keep coming back to your business or service, on their own. Lots of companies depend upon bringing people back to their businesses without spending a lot of money on spammy advertising and more messages to people's inboxes. So, instead what I'm going to teach you today is, a series of patterns, of design methods that you can use, to keep people coming back to your business. Now a bit about me, before writing this book Hooked, I've started to Tech companies, and in the process I learned a heck of a lot about how to keep users coming back. My last company was at the intersection of gaming and advertising, and these are two industries. Let's face it that are really dependent on mind control. So, I learned in these industries how to bring people back. So, what I'm going to share with you today, is the design methodologies, the techniques that these companies use, to make sure that people come back time and again. Now, I've taught this class at the design school at Stanford, and also at the Graduate School of Business there, and I also work with many companies here in Silicon Valley on how to keep their customers coming back. But you don't necessarily have to be building an App or a technology company to use some of these techniques. These principles are grounded in very old research from consumer psychology, and I'll provide you these tips and techniques that you can use, to bring customers back no matter what kind of business you're in. 2. Project: Design Your Hook: So, here's your class assignment. You're going to build your own hook. By understanding these four basic steps of the hook model, the trigger, the action, the reward, and investment, you can run your business through these series of questions to figure out if your business meets the pattern of these habit forming products. The first question to ask yourself is, what's the user's itch? What the internal trigger that will prompt your user to action throughout their day. The second question is, what's the external trigger, what's the piece of information, what the call to action that they're going to receive that's going to tell them what to do next? Then comes the action itself, the habit. So with the action phase the question is, what's the simplest behavior done in anticipation of a reward and how can that behavior be made as simple as possible? The next is the reward phase. So the reward phase, the key question here to ask yourself is, does the user get what they want? Is there a scratch and yet is there a bit of mystery, a bit of the unknown around what they might find the next time they engage with the product? Then finally the investment phase. The investment phase, the key question here is, what's the bit of work that the user is doing, what are they putting into the product to make sure they increase their likelihood of coming back through the hook once again? So, what are they doing to invest in the product and load the next trigger so that we make sure that they get this external trigger the next time they come through the hook. So, these five basic questions are your homework assignment. How can you answer these five basic questions to see if your business matches the design pattern of having this Hook model inside your user experience. So, the assignment for the class is to create your own hook to see if your product or service follows the design pattern that this course covers. The Hook has these four basic parts of a trigger, action, reward, and investment. So, answering these questions around whether you have these four basic steps in your product will help you uncover what deficiencies you might have in your product and where you have areas for improvement to make sure that you can form that user habit. As far as materials, all I'd recommend is taking out a piece of paper. You can even divide that paper into four squares, maybe you want to put trigger, action, reward, and investment inside each of those four squares and then ask yourself these five basic questions of what's the users itch, what's the external trigger that prompts the user to action, what's the simplest thing the user can do in anticipation of reward, is the reward fulfilling and yet leaves the user wanting more, and then finally, what the investment, what the bit of work the user does to bring themselves back to the hook once again? So, in terms of timing, you could take as long with this as you'd like. Most students take maybe about an hour to run through their first hook after they've understood the four steps of the Hook model of trigger, action, reward, and investment. Once you sit down and ask yourself, how does your business have the hook model built into it, you're going to start seeing some deficiencies, and you're going start seeing where you have areas for improvement and that's great. That's the whole point of the exercise, is to figure out how your business maps to the hook model. So, again, you can run this model again and again every time your itch changes for example, if you want to cater to a different internal trigger, then you're in and want to rerun the four steps of the hook or every time your key behavior changes, every time the habit changes, you're going to want to figure out how to run through that hook once again. The big insight from today's class is that these behaviors that we see ourselves kind of compulsively using, or maybe you found yourself checking Facebook, or Twitter, Instagram more than you'd like and you might think to yourself that it's just you. Well, it's not just you, and these behaviors don't happen by accident that in fact these behaviors occur by design. So, the takeaway that I want you to remember today, is that to create better user experiences, this isn't some happy accident. It doesn't just happen by mistake, it happens by design, it happens by being aware of what drives user behavior and then using consumer psychology to build the best product you can. So, let me give you some words of warning. So, some tricky parts where people tend to get stuck is when they can't figure out how their product fits the four steps of the model. That's great, that's exactly what this exercise is supposed to do. If you've come to this class with an existing idea, with a business that you'd like to turn into a product that people use time and time again. Well then if you're having trouble identifying what your trigger is, is the action easy enough, what's the reward and then finally, what the investment. If you're getting stuck on any of those areas, that's exactly what this exercise is supposed to do. It's supposed to make you re-evaluate. Why is this so deficient because if you don't know what your hook is your user won't either. But when you stumble, when you reach the speed bumps, that's good. That should raise a red flag to tell you this is an area where you need further exploration. So what makes a great project versus an okay project. A great project is one where the team finds out that there is some kind of deficiency in the existing product they're working on, right in the product or service that you're trying to turn into a habit. If you figure out wait a minute, there's something really missing here, we're missing a big chunk of the hook. A great project is one where they overcome that. Where they figure out wow we can use rewards of the tribe, hunt or sell for here's how we can make the action significantly easier, or wow, we were missing an internal or external trigger and now we figured out what we're going to do, or we were asking for an investment and now we will. Those are the kinds of projects that are great projects. That maybe started with part of the hook, maybe you didn't realize that you were missing a good chunk of what your product experience should have and now you've corrected it, now you've found a way to make sure that you have all four critical pieces. So remember the best way to learn is by actually doing, by answering some of these difficult questions to make sure that your product is going to be one that brings people back time and time again. Now, this was a short class. There's a lot more information in the extended Skillshare class about three hours. There's also a lot more information in my book, Hooked, how to build habit forming products with a lot more examples, tips as well as how to guide to help you where you might have stumbled. 3. The Hook Pattern: 4 Phases: Hi, my name is Nir Eyal and thanks for joining me for Hooked, How to Build Habit-Forming Products. If there's one thing that we've all seen over the past several years, is that these devices that we carry around with us have a profound impact on our day to day behaviors, and our day to day lives. So, what I've done over the past several years, is to research patterns. Is to try and figure out what it is about the world's most habit forming products, the products like Facebook, and Twitter, and Instagram, and WhatsApp, and Snap Chat, and Slack, how do these companies build products that keep users coming back time and time again? One thing that I noticed right off the bat was that many of these companies started out as toys. These products that were dismissed as features of somebody else's product. These little toys that wouldn't amount to much, and then within the blink of an eye, many of these products are touching the lives of hundreds of millions, if not billions of people, and they're making hundreds of millions, if not billions of dollars. So, what I wanted to do is to figure out how. How do these companies do it? So, I spent this past several years looking at these companies, and identifying patterns which I codified inside this book: Hooked How to Build Habit-Forming Products, which is a much more in-depth look at these habit forming behaviors. But today in this course, we're going to give you an overview of this model, of this book, but of course there's a lot more to learn in the book as well, so I encourage you to check that out. So, let's start out with what is a habit? Well, a habit is nothing more than an impulse to do a behavior, with little or no conscious thought. It's about 40 percent of what you do, day in and day out whether you like it or not, is done purely out of habit. Now, I believe that we're on the precipice of an age where we can help people build habits for good. Where we can improve people's lives using these techniques, and I'm not alone. Because today there's an explosion of companies around the world, that are using the psychology of designing for habits to help people live happier, healthier, more connected, more productive lives, and that's what I want to help you do, today. So, with that, here's the pattern. The pattern is called, the Hook. The hook is an experience designed to connect your users problem to your solution, with enough frequency to form a habit. So, by connecting your users problem to your solution with enough frequency to form a habit, this is how customer preferences are shaped, how tastes are formed, and how our habits take hold. 4. Phase 1: The Trigger: So, for the rest of the course, we're going to dive into the four steps of the hook model. The trigger, the action, the reward, and the investment. Let's first start out with triggers. Triggers are calls to action. They tell us what to do next, and they come in two types, two flavors if you will. We have our external triggers, and we have our internal triggers. Now, external triggers you'll be very familiar with. These are things in our environment, that tell us what to do next. Click here, buy now, play this, a friend telling you through word of mouth about a great new app you should try, all examples of external triggers. Now, we see these external triggers every day, as product designers, as entrepreneurs, as innovators, we may build many of these external triggers in people's lives. But what people don't consider enough, and what turns out to be absolutely critical, when it comes to forming these long term habits, is establishing an association with an internal trigger. An internal trigger, is something that tells the user what to do next. It prompts us to action, but the information for what to do is not in the trigger itself, remember that's what the external trigger does. The information for what to do is contained as an association or a memory inside the user's mind. So, what we do when we're feeling, when we're in a particular place, or when we're in a particular situation around certain people, when we partake in certain routines, or most frequently when we experience certain emotions dictates what we do next. Dictates the technologies, the products that we turn to with little or no conscious thought. It turns out the most frequent internal triggers are not just any emotions, they are negative emotions. So, what we do when we're feeling bored, or lonesome, or lost, or indecisive, or uncertain, what we do when we experience these negative emotions, prompts us to action. This is where we look for relief with the products that we use. Now, a great study that showed that this was the case came to us from a research study that found that people suffering from depression check email more. Now, think about that for a minute. Why would people suffering from clinical depression check email more? Well, it turns out that what we found, these researchers found, was that people suffering from depression, experienced what's called negative valence state. They felt down more frequently than the rest of the population. So, what were they doing to boost their mood to get out of that negative valence state? Well, they were checking their devices. They were going online more frequently than the rest of the population. Of course, if we're honest with ourselves, we all do this to some degree, right? What app do we go to when we're feeling lonely. Well, for many people that's Facebook. What about when we're unsure about something, before we scan our brains to see if we know the answer what are we doing? Well, we're googling it of course. What about when we're feeling bored, between two and four o'clock in the afternoon you have a big project you don't really feel like working on right now? That's a great time to head over to YouTube, or check sports scores, or stock prices, or check on the news or Pinterest. Lots of these products cater to this internal trigger of boredom. Well, so what do we do with this? It's a bit of interesting pop psychology, maybe you find that you in fact are triggered to use some of these products and services when you're feeling a bit down emotionally, but how do we build better knowing about the importance of these internal triggers. Well, it comes down to fundamentally understanding what is your user's itch. Look, it's very difficult to build a product solution for somebody, unless you can articulate what it is that you're solving for them, what's the problem, with the pain point, with the itch that's you that you are going to scratch. Let's do a quick case study. Let's start off with Instagram. Instagram is a very successful company, the product is doing incredibly well it went from being worth only a billion dollars when Facebook bought it. Now it's worth some $35 billion as part of Facebook. What made Instagram such a habit forming product. Well, let's take a look first at Instagram's external triggers. Well, the first time you've heard about Instagram, maybe you saw it on Facebook, maybe on Twitter, somebody posted a photo, and there was a big fat external trigger that said "Hey check out my foot on Instagram". You clicked on that button. You install the app. Now you've got the app on your phone. That's an example of an external trigger. Now you start getting these notifications from your friends. Those are all examples of external triggers as well. Well, after a while you start using the product. Let's think about what the internal triggers are. How does Instagram become the product that people use without conscious thought? Well, Instagram's internal triggers started from this sense of this fear of losing the moment. The solution to that problem, the scratch for that itch, is to capture that moment with Instagram. Now, that's the same internal trigger for all different kinds of photoghraphy products, but what makes Instagram special is that Instagram is also a social network. So, the more we use a product like Instagram, the more we pass through Instagram's hook, the more we begin to associate it with other internal triggers. Things like boredom or FOMO, we all know what FOMO is, the fear of missing out. It's actually a real word in the Merriam Webster dictionary as of two years ago. FOMO feels bad. We don't like that sensation of FOMO. So, to relieve that sensation that we might be missing out on something, all we have to do is to turn to this app in our pockets. 5. Phase 2: The Action: So, the next step of the hook is the action phase. The action phase is defined as the simplest behavior done in anticipation of a reward. Let me show you a few examples of some habit forming products and I want you to see just how simple these actions are. Something as simple as scrolling on Pinterest or searching on Google or what could be simpler than hitting the play button on YouTube. These incredibly simple actions done in anticipation of a reward. There's actually a formula to help us predict the likelihood of these behaviors that comes to us from a researcher by the name of B.J. Fogg who's at Stanford. Fogg tells us that for any human behavior B, we need three things. We need sufficient motivation, that's the M, We need sufficient ability, that's the A and we need a trigger, that's what we just talked about in the last lesson, the trigger. So, let's talk about the motivation and ability side of B equals MAT. Motivation is all about the energy for action. It's what makes us more or less likely to do a behavior based on how much we want to do it. Of course, motivation is one of these areas of psychology that psychologists have been debating about for decades and decades, but Fogg gives us these six basic levers that make someone more or less likely to do a behavior because all of us as human beings seek pleasure and avoid pain. We seek hope and we avoid fear. We seek social acceptance and we avoid social rejection. Now, there's a lot more to be said about user motivation, you can learn a lot more in my book. But for the sake of time, let's move on to the second part of B equals MAT. The A stands for ability. Ability is the capacity to do a particular behavior. How easy or difficult something is to do. Here again, we have these six basic levers of ability, these six things that make something easier or harder to do based on these six things, based on how much time something takes, how much money something costs, how much physical effort is required. Brain cycle, this is a big one if you're building a technology product, you got to think about how difficult the product is to understand as a direct correlation in how likely the behavior is to do that behavior. Social deviance tells us that will become more likely to do something when we see other people like us doing it. Finally, non-routine tells us that we become more likely to do something simply for the fact that we have done it before in the past. So, habits have this repeater effect. The more we do something the easier it becomes, the more likely we are to do it again in the future. So, you can ask yourself, if you can take any behavior you want a user to do, whether it's online or offline, doesn't matter, any human behavior you could run across a Fogg's behavior model and you can ask yourself, does the user have sufficient motivation? That's on the Y axis. High motivation is at the top, low motivation is at the bottom. Then on the X axis, you have ability. If something is very easy to do, it's way over there on the right. If something is very hard to do, it's over there on the left and if a behavior is easy enough to do and the user has sufficient ability, if they have sufficient motivation and sufficient ability, they cross this threshold. When they cross that threshold, if a trigger is present, the behavior will occur, every single time online or offline. Sufficient motivation, sufficient ability, when a trigger is present the behavior will occur. So, this is a very handy model. You can ask yourself, if users aren't doing the behaviors you want them to do which are they lacking? Is it motivation, is ability and then you can dive deeper into those six basic elements that we just described of both motivation and ability. Let's do another quick case study here. Let's take a look at Twitter and see how Twitter evolved over the years using these principles of motivation and ability. Here's Twitter in 2009. Here's Twitter in 2010 and here's Twitter in 2015. Now, what you will immediately notice from Twitter of 2015 versus Twitter of 2009, is that back in Twitter in 2009 there was a ton more stuff on this page. I mean look at all these buttons, look at all these triggers telling the user what to do. Click here, right. There's a what, why and how, watch a video, sign in here, sign up there. There's so much thinking that the user has to do to figure out the key behavior, which in all three examples 2009, 2010 and 2015, all three examples, all Twitter wants people to do in all three examples is to just sign in or sign up. So, what Twitter figured out was by removing the cognitive load, by making it easier for the user to figure out what it is you want them to do, they became more likely to do it and Twitter increased their conversion rate and they could start sending people through the four steps of their hook. So, that's what I want you to do. I want you to consider for yourself what are the steps that are involved with getting from the internal trigger, which we just discussed in the last class that itch that the user feels, to the reward. What's the simplest thing the user can do to relieve their itch? 6. Phase 3: The Reward: The third step of the hook is the reward phase. Now, when it comes to rewards, we have to talk about the brain and in particular, an area of the brain called the nucleus accumbens, which was first studied by two Canadian researchers by the name of Olds and Milner. Olds and Milner discovered they were the implanted electrodes inside the brain of lab animals. They allowed these lab animals to push on a little lever, to send an electrical current to this part of the brain. What they discovered was that these lab animals did so incessantly. They would forgo food and water. They would run across painful electrified grids just to continue to activate this very special part of the brain. Now, in later experiments done on people, they actually observed similar results. That when people were given these little buttons to press on, and every time they pressed on the button, they would receive an electrical jolt to their nucleus accumbens, they did so hundreds of times. Some of the people in the studies had to have the machines forcibly removed from them to get them to stop activating this part of the brain. Well, it turns out we don't need electrodes to activate the nucleus accumbens because all sorts of things activate your nucleus accumbens every single day. Things like luxury goods, junk foods, sex, certain chemicals, and of course right there in the center, technology. All of these things activate your nucleus accumbens every single day. Now, for decades, much of the psychology community and Olds and Milner believe that the purpose of the nucleus accumbens was to stimulate pleasure, right? Why else would lab animals and later people incessantly activate this part of the brain if it wasn't because it felt good, right? Well, not exactly. What we now know is that the nucleus accumbens does not necessarily get us to act by stimulating pleasure per say, but instead the brain gets this to act by activating what we call the stress of desire. Because what we now know that Olds and Milner never did was that the nucleus accumbens becomes most active in anticipation of the reward. But when we actually get the thing we want, the thing that's finally going to make us happy and we think we're going to feel good, that's when the nucleus accumbens becomes less active. So, the way the brain gets us to act is by activating this itch that we seek to scratch. It turns out that there is a way to supercharge this stress of desire. Would you like to know how? Are you curious?Exactly. What I just did right now by asking you a question and taking that long pause, maybe you perked up. What am I going to say next? What's the answer? It turns out that in all sorts of experiences that we find most habit forming, most engaging, you will find this element of mystery, a bit of variability. Now, this of course comes from the classic work of BF Skinner. You might remember Skinner from your psychology 101 class back in college. That Skinner took these pigeons, he put them in a box, and he gave these pigeons a little disk to peck at. Every time pigeons pecked at this disk, they would receive a little reward. They would get a little food pellet, and quickly what Skinner discovered was that he could train these pigeons to peck at this little disc whenever they were hungry. Terrific. But then, Skinner did something a little bit different. Skinner introduced a variable reward. So, sometimes the pigeons would peck at the disc, and nothing would happen. No food pellet would come out. The next time the pigeon would peck at the disc, they would receive a reward. What Skinner observed was, that the rate of response, the number of times these pigeons pecked at the disc increased when the reward was given on a variable schedule of reinforcement. Why does this happen? Because we now know that variability spikes activity in the nucleus accumbens creating this wanting, this craving reflex. So, in all sorts of products that we find most engaging, most habit forming, the things that capture our attention and won't let go, you will find one or more of these three variable reward types. Rewards of the tribe, rewards the hunt, and rewards of the self. Let me introduce to you real quick. So, rewards of the tribe. These are things that we look for that feel good, that have this element of variability, and come from other people. This is all about the search for empathetic joy. Feeling good because someone else feels good, partnerships, cooperation, competition. Best example I can think of online, social media. Right. When you open up your Facebook app, and you scroll through your news feed, you're never quite sure what you're going to find. What pictures that people post? How many comments does something get? How many likes do you get? All of these things have an element of variability. They have this uncertainty that's connected to other people. The next type of variable reward, is the rewards of the hunt. The search for resources. This stems from our primal search for food and other material possessions, and in modern society we buy these things with money. So, when many people think of variable reward, they oftentimes think of gambling. They think of pulling on a slot machine, where the variable reward is of course the coins, the points, the money that you get out of these games of chance. Well, it turns out that we find the exact same psychology at work online. That when we scroll through a feed, for example on LinkedIn, or Twitter, or any number of other apps, Pinterest for example, all of these apps incorporate this idea of a feed. Well, searching on a feed and scrolling and scrolling and looking for that next interesting piece of content actually use the exact same psychology that keeps us pulling on a slot machine. They're both variable rewards of the hunt. The last type of variable reward is the variable reward of the self. This is all about the search for self achievement. This is about the search for mastery, consistency, competency, and control. Good example of this online is game play. Where if you think about why people play Angry Birds, or the Kardashian game, or dots, or Candy Crush, any of these games, we are playing not necessarily because we're winning anything. We're not really playing them with other people, but there's something very fun and enjoyable about getting to the next level, the next accomplishment, the next achievement. Now, some people say to me, "Yeah, that's great near." But listen, I don't really play games. This doesn't really apply to me. Well, I bet you play this game every day. That unread message in your email inbox, the to do's on your to do list, or when you see an app notification on your screen that you just have to open so you can clear it away, these are all examples of variable rewards of the self. The search for mastery, consistency, competency, and control. So, one word of warning before we close out this lesson is that variable rewards are not a free pass. That we have to be very careful about putting in variable rewards willy nilly. That's not how it works. We have to connect the variable reward with the internal trigger. So, if the internal trigger is about satiating boredom, well then, the variable reward has to entertain. But if your internal trigger is something completely different, let's say it's about loneliness, seeking connection, well then we have to connect people together. So, there is a fundamental connection which is why it's so important to understand what that itch is that you're scratching for your users because the point of the variable reward phase is to give people what they want, to make their lives better, to alleviate their pain points, and yet have this bit of mystery, this bit of uncertainty around what they might find the next time they engage with the product. 7. Phase 4: The Investment: The last part of the Hook is the investment phase. Now, the investment phase is where the user put something into the product in anticipation of a future benefit. Remember it's not about immediate gratification. That's what the action phase is for. The action phase is about alleviating my pain as quickly as possible. The investment phase is not about that. The investment phase is something the user does for a future reward. Now, the point of the investment phase is to increase the likelihood of the next pass through the Hook. Investments increase the likelihood of the next pass through the Hook in two ways. The first way is by loading the next trigger. Now, let me give you an example. When I use WhatsApp or any number of other messaging services, and I send someone a message, there's no immediate gratification there, right? Nothing really happens when I send someone a message, but what I'm doing, by sending someone a message is that, I'm loading the next trigger because I'm likely to get a reply. That reply comes coupled with an external trigger that prompts me to pass through the Hook once again. Now, that's the first way that investments increase the likelihood of the next pass through the Hook. Here's the second way. It's called storing value. So, investments increase the likelihood of the next pass of the Hook by getting the user to store value in the product. It's one of the reasons I love working in technology as opposed to working in physical products like my clothing or this table, or anything in the physical world loses value with wear and tear. It depreciates over time, but habit forming technologies and habit forming products should get better with use. They should appreciate in value. They do this because of this principle of stored value. So, for example, when I add content to my Google Drive, it becomes better and better as my one and only Cloud storage solution. The more data I give to a personal finance software like Mint.com, or data I might give to a company like Pinterest, the better it becomes. I can do more with those products and services based on how much data I give them. Followers, Twitter becomes a better way for me to reach my audience, the more of the bigger audience I have. So, if Twitter were tomorrow to send out an email, it said, "Hey, guess what, we're going to turn off Twitter unless you start paying us." Who's more likely to start paying. Is it going to be someone with 10 followers or 10,000 followers? Of course, it's going to be the person with 10,000 followers because they've stored all this value in the product. The product has become more valuable to them, the higher their follower count is. Finally, reputation. Reputation is a form of stored value that users can literally take to the bank. Because my reputation on sites like Airbnb, or TaskRabbit, or eBay dictates what I can charge for my goods and services, and how likely am I to leave one of these platforms after I've spent all this time and effort accruing a positive reputation. It's kind of hard to leave. It's kind of hard for me to go. 8. Wrapping Up: So, in this last section, we're going to do a quick review of the four steps of the hook model. The trigger, the action, the reward and the investment that through successive cycles through these hooks, this is how customer preferences are shaped, how tastes are formed, and how these habits take hold. Now, this was a very brief introductory course. There's a lot more information in the book Hooked: How to Build Habit-forming Products. I suggest you check that out. There's a lot more examples, there's a lot more case studies and there's a lot more how-to of how to make sure that your product will be habit-forming. But here are the five fundamental questions. Here's the most important slide of the entire presentation. These five fundamental questions that you'll need on the assignment for this product as well, which is, number one, you've got to be able to answer, what is your internal trigger? What's the itch that your product is attempting to scratch? Number two, what's the external trigger? What's the thing that gives the user some piece of information to prompt them to action, to take that habit? Number three, what's the simplest behavior the user can do in anticipation of an immediate reward and how can it be made even easier? Then, the reward itself. Is the reward fulfilling and yet leave the user wanting more? Then finally, what's the investment? What's the bit of work that the user does to increase the likelihood of the next pass through the hook? Now, not every business needs a habit. Plenty of companies out there can bring people back to their place of business without forming a habit. They can use advertising, they can use search engine optimization, heck, you can have a physical storefront on the corner to get people to your place of business. So, not every business needs a habit, but every business that needs the habit has to have a hook. So, if you're building the kind of business that requires unprompted engagement, people coming back on their own, make sure you can fill out all of these five questions and build your own hook. Now, there's one more thing I'd love to discuss with you before this session ends. That when we talk about changing people's behavior, we need to talk about the morality of manipulation. This is something that we should be concerned about. Because when we design products for people to change their behavior, to meet our ends in mind, that my friends is a form of manipulation. We need to be very careful about how we apply these techniques, because let's face it. That many of the products we use and many of the products that we're building are the kind of things that people take to bed with them every single night. It's the first thing we reach for in the morning before we even say hello to our loved ones. As Ian Bogost said "our technologies are quite possibly becoming the cigarettes of this century." So, I ask you to consider what responsibility do you have to use the psychology of habits for good? What I'd like you to do with this is to use this for good, is to help people build healthy habits, to help them live happier, more connected, healthier lives, by using the psychology of habit for good. I encourage you to borrow from the words of Gandhi to build the change that you wish to see in the world. With that, thank you very much for joining me on this course. I hope you build lots of great habit-forming products.