A Case Study on the Successful Gamification of Duolingo

A deep dive into the mechanics and clever tricks that Duolingo employs in order to keep their users engaged and productive.

Quick Note: If you’d like to listen to this post instead of read it, check it out on Substack, where I post weekly with voiceovers. Find it here.

I was sitting at my desk this evening, when I suddenly felt perturbed by the appearance of a particular notification on my phone screen. A small red countdown telling me that I only had a couple of hours to complete my lesson of the day before all of my hard work would go down the drain. As stress began to nag at me, I decided I may as well do my lesson, that way I didn’t have to worry about doing it later.

Duolingo is a masterclass in the art of “Gamification”, utilizing a clever array of systems and tricks to keep their users engaged, to the benefit of said users. Gamification, if done correctly and ethically, allows for a little bit of play in an otherwise somewhat serious environment. My streak is well over 600 days strong at time of writing, partially because I’ve convinced myself that it’s a worthwhile habit, but mostly because Duolingo provided a platform for me to do so.

The draw

I want to start by describing to you what Duolingo does to engage you, before you’ve even opened the app. Successful execution outside of the application comes down to one feature of modern operating systems: the “push notification”.

A key feature of mobile operating systems is their ability to receive and organize push notifications from various sources conveniently. Notifications are the main interface through which applications prompt their users to engage with them. Therefore, it’s reasonable and correct to assume that Duolingo makes good use of such notifications.

In a timely manner…

First off, it’s worth mentioning that it was late evening when I received my notification, around 10pm in fact. This is significant because I’ve received the same notification every day for the past two years, almost always around 9 or 10pm. Duolingo monitors usage patterns to infer when you’re most likely free for a lesson. Then, based on this information, the application will send you notifications at specific times to maximize chances of gaining your engagement.

Read the room…

So what is the nature of these notifications? As it turns out, this clever application has a few different flavors of notification which it sends depending on the context:

If the user hasn’t logged on for a while, they will receive spaced out notifications encouraging them to log back into the application.

This strategy lets Duolingo target a specific subset of users. These are individuals interested enough to install the app but not committed to a regular routine. A surprising amount of people will be willing to install an application that they think is interesting, and a smaller but still significant portion of those will even use the application for a bit before logging out and forgetting about it. However there also exists a percentage of those who would return to the application with a lucky prompt.

If the user has a streak, a special notification with a timer will be used, with a red lettered countdown to indicate time before streak expiration.

Speaking of routines, possibly the most notorious and one of the most critical aspects of Duolingo is the “streak”. Without getting too far into it yet, the streak speaks to a specific subset of users who have certain tendencies, goals and motivations. These are the users which have inertia, and are incentivized to keep it in order to maintain their tracked consistency. For these users, the key is to prompt them with a reminder that their inaction threatens their hard-earned streak. Taking the 5 minutes becomes the obvious, albeit difficult, choice.

The user is ranked based on “XP” collected through taking lessons over time–among other factors, and significant movement through these rankings alerts the user.

This is one of the more blatant gamification aspects to the Duolingo application. A leaderboard is a way to see your position in a sort of hierarchy, which presents each user with the goal of reaching the top. Leaderboards are sorted into “leagues”, which group users or “players” into different levels. Higher levels can be achieved by increasing your XP through lessons and activities, and subsequently moving up to the “Promotion Zone”. After a set period of time, those in the “Promotion Zone” will rise to the next league, while those in the “Demotion Zone” will fall.

If a friend accomplishes something such as moving up in rankings or logging on for the first time, users are notified in order to give them encouragement.

Fostering a sense of community and camaraderie is an excellent way to motivate users to continue towards their goals. As social creatures, we thrive in environments with encouraging piers. If my wife hasn’t logged on to do a lesson in a while, and opens the app for whatever reason, Duolingo offers me the chance to send her “applause”. This kind of social aspect provides a careful mix of pressure and encouragement. If used correctly, this force can convert those teetering on the edge of commitment into regular users.

Overall, Duolingo uses notifications quite aptly, relying on pattern recognition and careful timing to increase success. Successful use of push notifications is crucial to drive engagement, as it gives users both a nudge, as well as an opportunity. A user can easily swipe away a push notification if they desire, but oftentimes they installed your application for a reason, and so reasonable and well-placed notifications are welcome.

Consistency is key…

Besides notifications, one of the cornerstones of Duolingo’s success is the use of the “streak”, which is a running meter of how many days in a row one has practiced. A feature present since Duolingo’s 2012 launch, this particular gamification technique has become popular across the industry. The streak has proven extremely effective at driving engagement, with over 3 million Duolingo users possessing a 365+ day streak in early 2023.

But how does this clever trick work under the hood? I’m not talking about the software, I’m talking about our software. What makes me go back day after day to complete the language lesson that I usually don’t initially feel motivated to do? As it turns out, this seemingly simple gamification technique is effective on us humans due to the convergence of a variety of inherent psychological phenomena.

The behavioral exchange rate…

First off, business majors and economists among us might be familiar with the concept of the “sunken-cost fallacy”:

the phenomenon whereby a person is reluctant to abandon a strategy or course of action because they have invested heavily in it.

This cognitive bias manifests as the result of some more fundamental aspects of human nature, such as “loss aversion”. Loss aversion is a principle within behavioral economics where the pain of losing is more psychologically powerful than the pleasure of gaining. This leads to a sort of “behavioral exchange rate” where cognitive energy is allocated favorably to risk aversion at the expense of a possible pleasure gain.

There are evolutionary roots to this, with theories suggesting that organisms are predisposed to minimize their costliest actions. In error management theory, the perceived cost of such actions would outweigh the benefits of equivalent gains. Thus, overestimating the impact of losses would be less costly than underestimating them, leading to our cognitive bias towards negativity.

Duolingo uses this method, because they know that once you’ve got a high enough streak, you’re significantly less likely to risk losing it. Therefore, you’ll continually log into the application in order to maintain your hard earned streak. Some leeway is given through things like “streak freezes”, which allow for intermittent skipping of lessons, however these can only be purchased using an earned in-app currency.

However, while this might sound like some subliminal trickery afoot, the learning benefits of such an approach are also psychologically sound.

The habit loop…

The most important aspect to keep in mind is the dopaminergic reward system that guides our habits. Habit formation allows our brain to prioritize, mechanize, and reinforce certain behaviors which have historically lead to rewarding outcomes. While many see dopamine as a sort of “hit” that they gain from certain immediately-gratifying activities, in reality dopamine is more like the ebb and flow of the tide.

The system looks more like a generally higher level of dopamine during a rewarding activity–often manifesting in happiness or euphoria. Over time, as you repeat certain actions and receive corresponding pleasurable outcomes, your brain learns to release more dopamine during those activities, eventually forming a “habit”. When a certain stimuli is perceived in relation to this activity, it triggers your brain to move towards the behavior that is correlated with higher dopamine release.

This is why hearing the sound of a game console turning on might prompt you to pick up a controller. It’s also why the sound of your phone receiving a notification will often prompt you to turn it on. This is where gamification comes in, because this concept is heavily utilized by game design to create stimulating, engaging and habit-forming experiences. Which can be very tricky and even addictive when used unethically, but also has huge potential for benefits.

Learning through habit…

Consistency is key in most any quest for improvement, whether that be learning, exercise, or skill development. This is because habit formation, and associated systems, are also responsible for memory management. Memory consolidation is the process by which temporary memories are gradually converted into a more permanent form in the brain.

The decisive factor is whether certain information has actually proven useful, which is measured by its correlation with rewarding behavior. When you do a lesson every day on Duolingo, your brain decides that this new language information will likely come in handy in the future, therefore giving it a more permanent residence. This effect is also why it’s important to review notes hours, weeks and even months after initially taking them.

Additionally, spreading learning out across multiple lessons decreases the cognitive load for an individual session. This means that while you’re not likely to learn as much from an individual lesson, your comprehension will likely be higher, and application of the material more effective. Cognitive load is what prevents “cramming” from being a useful learning strategy, as your brain can only take in so much information at once. Like most things in life, learning is more like tending a garden than striking gold — consistent care yields lasting growth, not sudden windfalls.

Other benefits of habitual learning include:

1. Improved Metacognitive Skills: Metacognition involves awareness and regulation of one’s own learning processes. Consistent learning habits help learners better understand their own learning strategies and adapt them more effectively.
2. Increased Neural Plasticity: Neural plasticity is the brain’s ability to reorganize itself by forming new neural connections throughout life. Regular intellectual engagement is known to stimulate plasticity.
3. Stress Reduction: High-stress levels, which can be exacerbated by cramming large amounts of information at once, can negatively impact brain function, particularly in areas involved in memory and learning.
4. Formation of a Learning Routine: Routines can lower resistance to tasks by making them a regular part of one’s day, reducing the effort required to initiate the task.

So Duolingo has really hit the mark with their use of the streak. It’s an effective tool for driving engagement, but also has many implications for effective learning. The key takeaway is to use the streak effectively, and align its power with the value that you hope to give your users.

All fun and games…

While gamification is essentially the introduction of game design features into more traditional applications, Duolingo has taken it to the next level. It’s easy to implement game design elements into your application, but to make your app feel like a game takes more effort. This is because there’s an inherent immersion required to make someone feel as if they’re playing and not working, while still driving productivity.

Do no evil…

There’s a reason why attempts at gamification such as Google News Badges ultimately weren’t fruitful, and it’s because they fail at immersion. Google News Badges were a feature released in 2011 where as you read news, you’d be rewarded with increasingly shiny badges. The idea was to drive engagement with news and other content, but also allegedly allowed Google to increase ad revenue and data collection on users.

Google might have found more success if they had attached some real value to these badges, however users ultimately didn’t find them meaningful. In Duolingo, rewards are directly correlated with the user’s effort towards their own fulfilling goal. First, the user has decided that learning a new language would be beneficial to them, so they go to Duolingo. Second, Duolingo provides them with what feels like a game, in order to guide their learning effectively.

This alignment of goals allows the user to have an engaging experience, where they also feel fulfilled by the end of it. The XP that one earns by completing their lessons feels like it measures something meaningful, rather than something arbitrary. Thus creating experiences which are engaging but altruistic are much more likely to be effective.

Organic is better…

Simply aligning your experience with your end-user’s goals isn’t enough to ensure quality, and bad user-experience can kill a good gamification attempt. The key is to create an organic experience, where the user or “player” can easily navigate the environment, identify constraints and pursue rewards. Duolingo does this by providing a very straightforward and smooth experience, without compromising on fun.

The first thing a user sees when they log into Duolingo is a prompt to start a lesson, right where they left off the last time. Using moving elements, bold colors, and shiny iconography, the app guides your attention towards the most obvious next action. Everything else is in pursuit of this central goal, and minimizes friction. While I’ll leave the UX design to better-suited authors, it’s important to consider that games with friction are much less enjoyable.

It’s all a game…

Duolingo’s entire app feels more like a game than anything else. Yes, they provide quality educational content and resources, but it still feels like I’m a player, trying to navigate an arena in order to gain rewards. This is the immersion that I’m talking about, where the gems and points don’t feel out of place, but rather make complete sense in the context.

When you look at the amount of gems that you have access to, it’s also pretty easy to figure out how to get more. When you see your ranking on the leaderboard, the steps required to level up are fairly obvious. Every reward mechanism simply makes sense, and fits well with the others. Every game element composes a greater game arena, where the key to success is consistent lessons.

So, what’s the point?

Gamification is definitely a fun idea, but there is reasonable skepticism about the efficacy of such an approach. Are we creating a culture of infanticization where people are trained to do what they’re told through colorful and stimulating experiences? Or are we building tools to help malintended companies addict their users for capitol gain? These are real concerns which need to be addressed if we’re going to see the benefits of this approach.

But there are benefits, and Duolingo is an excellent case study into harnessing them. With it’s intelligent use of notifications, engaging elements such as the streak and XP, and a real value-add to the end-user, this app gets things right. Their successful implementation has ultimately led to Duolingo’s growth and popularity, amassing over 21 million daily active users. If you’re looking to gamify your system, look to Duolingo for inspiration.

Author’s Note

Thank you so much for reading! This is my first post here on Substack so I hope that you enjoyed it! There will be many more to come, including updates to the audio quality of the voiceovers. I’d love to hear your thoughts in the replies, and I’m always open to feedback!