The Psychology Behind Duolingo’s Success

Duolingo, a popular language-learning app which went public in 2012, is currently the most downloaded education app in the world today. But what has contributed to its staggering success?

A plethora of education apps and innovative tech exist in this space, yet Duolingo maintains its dominance over competitors: currently making up for 60% of all language learning app usage. Its success is not just a product of innovative technology but also a testament to the clever application of psychological principles. By leveraging key concepts from behavioral science, Duolingo has transformed the process of learning a new language into a fun, addictive, and rewarding experience.

The Rise of Personalization and Gamification

According to a McKinsey report, with the rise of Covid-19 in 2020, consumers began to expect that brands demonstrate that they know them on a personal level, more frequently than before–with the surge in digital behaviors increasing the need for better quality interactions. Three-quarters of consumers switched to a new store, product, or buying method during the pandemic. In their consideration of a brand, they sought personalization: “Our research shows that 71 percent of consumers expect companies to deliver personalized interactions. And 76 percent get frustrated when this doesn’t happen” (McKinsey). The consumer’s need for personalization continues to rise.

Gamification is also on the rise: gamification involves drawing inspiration from video games when designing a product, with a focus on understanding and incorporating human motivations into each feature. According to a report by Precedence Research, “the global gamification market size was evaluated at USD 10 billion in 2022 and it is projected to surpass around USD 116.68 billion by 2032, poised to grow at a CAGR of 27.9% during the forecast period 2023 to 2032.” Gamification and personalization use psychology to maximize consumer retention and motivation. When increasing contact with the consumer, there is a directly correlated increase in revenue, retention, and app usage. Duolingo has taken advantage of this fact.

Duolingo’s success is a testament to its effective use and application of several psychological principles. Including:

1. Gamification
2. Behavioral Economics
3. Social Influence and Competition
4. Personalization and Communication
5. Cognitive Science

Duolingo has created a compelling and effective language-learning platform. Its innovative approach not only makes learning a new language accessible and enjoyable but also taps into fundamental psychological drivers to keep users motivated and engaged. Let’s analyze how they incorporate these elements and what makes them so addictive, sticky, and successful.

Gamification

One of the core elements of Duolingo’s approach is integrating these video game-like elements into the learning process to enhance motivation, user activity and engagement. These rewards serve as extrinsic motivators that drive continued participation. It’s a powerful strategy in digital marketing and customer retention, transforming mundane tasks into exciting challenges. Loyalty in gamification creates an emotional connection, making everyday interactions fun and rewarding. Integrating gamification with loyalty can significantly enhance customer engagement levels, as seen in platforms like ours, which provide gamification loyalty tools to incorporate these mechanics into various business models.

Duolingo is simultaneously both a language-learning app and a video game. It incorporates common video game elements to make learning more of a fun journey for the consumer. Gamification is great at making an app “sticky.” This essentially means that users will make a habit of using it. Here are some examples of how Duolingo makes their app sticky through gamification:

1a. Experience Points and Level Progress

1b. Immediate Feedback

1c. Awards (Badges)

1d. Tasks

1e.  In-game Microtransactions

1a. Experience Points and Level Progress

Like many video games, Duolingo tracks your level progress, and you earn more Experience Points (XP) as you advance to higher units or sections within the language course. XP provides a sense of progression and accomplishment. Within a specific unit, the app lets you know when you get 5 or 10 correct answers in a row. In Duolingo, you can visualize your progress with the progress bar and simplistic map on the homepage. Users can see their progress visually through progress bars that fill up as they complete lessons and advance through levels. This visual representation of progress goes a long way in keeping users motivated and focused on their language-learning goals.

1b. Immediate Feedback

Duolingo provides immediate feedback on users’ responses, which taps into the psychological principle of operant conditioning. This immediate reinforcement helps users quickly learn from their mistakes and reinforces correct answers, keeping them engaged and motivated.

1c. Awards (Badges)

According to Salesflare, there was an impressive 116% jump in referrals due to Duolingo’s badge reward system. Badges are an excellent example of how gamification can garner interest and increased commitment to an app like Duolingo. Badges fulfill the basic human need for self-worth, an important intrinsic motivator. Users can look at their earned badges and review their progress, or compare with friends (this competitive and social aspect will be discussed more later in this article). It is essential to point out that referrals are an invaluable resource because they are the most effective form of lead generation, as social media shares and word of mouth referrals require zero financial investment and bring in customers who are more likely to stick around–increasing user retention.

Not only does Duolingo use a badge reward system to boost dopamine within the brain’s reward system, but also treasure chests or gems–digital currency that can be used on the app’s built-in store. All of these gamification mechanisms amplify user activity and engagement.

1d. Tasks

Another way Duolingo keeps users motivated is by utilizing tasks such as challenges, daily goals, or quests. Daily goals or quests such as completing 2 lessons in one day, or monthly challenges can keep users motivated and committed. Challenges are monthly competitions where users attempt to complete 20 to 50 quests to earn the badge for that month. The frequency of the daily and monthly tasks provide a structured schedule which helps with effective stickiness when applied to the language-learning app.

1e. In-game Microtransactions

Another common method/mechanism adapted from popular video games such as NBA 2k, Fifa, or Clash of Clans: in-game microtransactions can help generate substantial revenue. The blue gems in the top right hand corner of the app are Duolingo’s form of digital currency. Gems can be used to purchase items in the Shop. These include: heart refills, XP Boosts, Timer Boosts, Streak Freezes, Merch, and more options like special offers. These items allow for Duolingo to generate and accrue more revenue while keeping the consumer hooked. The idea of the hearts is crucial, as it gives a sense of failure when you lose all your 5 “lives” during a lesson on basic phrases for example. But just like in other video games, you can buy back your lives with heart refills – to increase your ‘lives’ when answering questions, so that you don’t have to worry about making mistakes. You can also buy gems with real money. If you don’t have enough gems on the game to purchase an item of your choice, you can always purchase more.

Finally, Duolingo captures another gamified element: premium subscriptions. Duolingo offers a premium subscription, Super Duolingo, which offers several benefits, including: No ads, unlimited hearts, personalized practice-on demand, free entry to legendary and timed challenges, and mistakes review to target your weak areas. The app gives a free 2 week trial period before billing $12.99 a month. There are family and annual options as well. As of the end of the second quarter of 2024, Duolingo had 8 million paid subscribers worldwide.

Additionally, Duolingo Max is another new premium subscription that incorporates interactive artificial intelligence into your learning experience. Clearly this model has shown major success and projects continued growth for the near future.

Behavioral Economics

Duolingo’s design cleverly incorporates principles from behavioral economics to promote habit formation and user retention, mainly through streaks and consistency as well as microlearning.

The app emphasizes daily practice with its streak feature, which tracks how many days in a row a user has completed lessons. This creates a sense of commitment and helps build a learning habit. The fear of breaking a streak can be a powerful motivator, encouraging users to keep up with their practice. Maintaining a streak of consecutive days is a great motivator to visit the app daily, thus increasing the retention rate and user engagement for Duolingo. Gamification is used to incentivize behavior in users. The streak system incentivizes persistence and commitment–encouraging customers to engage more deeply and frequently with the platform and ensuring a sticky experience. Additionally, users offered a streak wager see a 14% boost in day 14 user retention.

Duolingo also uses Microlearning, breaking down language learning into small, manageable tasks or “micro-lessons.” This approach leverages the concept of “chunking,” which makes the learning process feel less overwhelming and more achievable. It also aligns with the principle of “nudge theory,” where small, incremental steps guide users toward their goals. Both microlearning and streaks help increase user retention and activity.

Social Influence and Competition

Duolingo does an excellent job adapting elements from video games and apps. It incorporates streaks, a tactic largely made popular by Snapchat. But it also utilizes seminal gamified mechanisms like the Leaderboard, where users are ranked based on performance.

Social psychology plays a major role in Duolingo’s success, especially through its main social/community features: Leaderboards and Social Sharing. Duolingo incorporates leaderboards and weekly challenges, which introduce a competitive element. This taps into social comparison theory, where users are motivated to compete with others and improve their ranking globally. Users can also share their achievements on social media, which leverages social proof and encourages engagement through external validation. You can add friends from your contacts or invite them to join the app. There is a built-in timeline/feed on Duolingo as well. This aspect of social interaction adds a layer of accountability and motivation amongst friends and strangers around the world.

Personalization and Communication

Each user has their own personalized homepage with achievement/awards, follower count, personal records/stats, and more. Duolingo uses personalization in various ways, including its famous owl mascot and widget, feedback/push notifications and communication, AI, premium features, and more. Personalization is another key psychological tactic Duolingo uses to enhance user engagement. For example, Duolingo’s green owl mascot, Duo, gives a friendly and personal touch to the brand, whether seen in the context of the app, or more notably, the push notifications. Adding the mascot, Duo, to push notifications makes it more personal. The mascot’s friendly appearance in push notifications led to a 5% rise in daily active users. Premium features and AI allow users to have speaking/listening conversations, as well as personalized collections of stories, words, and mistakes. In addition, Duolingo personalizes your learning experience with adaptive learning and goal setting/progress tracking.

Duolingo adapts to users’ learning styles and proficiency levels by offering customized content. This personalized approach ensures that users receive lessons that match their current skill level, making the learning experience more relevant and less frustrating. The app also allows users to set goals and track their progress, which taps into the psychological principle of self-efficacy. By seeing their progress and achieving milestones, users gain a sense of accomplishment and are much more likely to stay motivated and engaged with the app.

Cognitive Science

Before analyzing specific cognitive science methods and mechanisms used by Duolingo, we must discuss the topic of interest, and how it develops over time in a pattern. According to a Stanford study, “The Four Phases of Games and Interest,” there is a Four-Phase Model of Interest Development and video games or gamified learning experiences use this framework or model to drive towards intrinsic motivation: The Four-Phase Model of Interest Development is a theoretical framework that describes how a person’s interest in a topic or activity can evolve over time.

The model considers both affective and cognitive factors that are involved in the development and deepening of interest. It also suggests that educators can play an important role in facilitating interest development by providing appropriate triggers, supports, challenges, and feedback for learners at different phases of interest. It was proposed by researchers Suzanne Hidi and K. Ann Renninger in 2006. According to this model, there are four phases of interest development:

1. Triggered situational interest: This stage arises when something in your environment captures your attention or sparks your curiosity, often something novel, unexpected, or challenging. It is typically short-lived and depends on external stimuli that trigger it.
2. Maintained situational interest: This phase occurs when your interest and engagement in a subject or activity are driven by the elements that facilitate your learning, such as the content, the instructor, your peers, or the feedback received. This stage can endure longer than the initial interest and has the potential to deepen your learning and comprehension.
3. Emerging individual interest: This phase happens when your affinity for a subject or activity intensifies due to your existing knowledge, personal desires, values, and self-concept. It endures for a more extended period and possesses greater strength compared to situational interest, motivating you to pursue further learning and engagement.
4. Well-developed individual interest: This stage occurs when you possess an enduring passion that imbues you with a strong sense of knowledge and proficiency in a particular subject or activity. It compels you to invest significant time and effort willingly. This phase represents the utmost level of self-motivated and independent interest, capable of profoundly influencing your identity and pursuits

Duolingo’s success relies heavily on its ability to not only pull in users with interest and intrigue, but also in its retention and ability to maintain that interest for extended periods of time.  It uses gamification elements such as points/levels, badges/awards, streaks, leaderboards, and more to motivate learners to practice their language skills. Duolingo also uses narrative and immersion techniques to foster a deeper connection with the learner. All of these techniques and mechanisms help immensely with user engagement, retention, and motivation.

Here is how Duolingo uses interest to their advantage based on the Four Phase Model of Interest Development:

Triggered situational interest: Duolingo triggers situational interest by presenting a variety of topics, exercises, and stories that are relevant, novel, and challenging for the learners. For example, learners can choose from over 40 languages to learn, from Spanish and French to even Klingon. Learners can also select from different courses that match their goals, such as travel, culture, or career. Learners can also access interactive stories that immerse them in different scenarios and contexts. Duolingo also uses dynamic music and sound effects to create a captivating atmosphere and mood.

Maintained situational interest: Duolingo maintains situational interest by providing feedback, guidance, and reinforcement for the learners’ progress and performance. For example, learners can earn points, level up, unlock new skills, and collect badges as they complete their lessons. Learners can also see their progress and improvement through the app’s dashboard, which shows their fluency score, streak count, and XP rank. Learners can also receive tips, explanations, and corrections from the app’s AI tutor, which helps them learn from their mistakes and master the language concepts. Duolingo also supports the learners’ interest by allowing them to interact with other learners online, who can help or hinder them in their journey. For example, learners can join clubs, compete in leagues, chat with friends, and send each other virtual gifts.

Emerging individual interest: Duolingo fosters emerging individual interest by allowing learners to customize their goals, preferences, and learning paths, as well as reflect their values and identity through the language they choose to learn. For example, learners can set their daily goals, choose their preferred learning style, and adjust their difficulty level. Learners can also follow their own pace and sequence of learning, and revisit the skills and topics they want to review or practice. Learners can also express their creativity and identity through the language they learn, as they can explore different cultures, histories, and perspectives through the app’s content and stories.

Well-developed individual interest: Duolingo nurtures well-developed individual interest by creating a sense of mastery, achievement, and enjoyment for the learners, as well as opportunities for socializing and sharing with other learners. For example, learners can access advanced features and exercises, such as podcasts, documentaries, and quizzes, that challenge and enrich their language skills. Learners can also earn certificates, trophies, and medals that recognize their accomplishments and proficiency. Learners can also have fun, be creative, and challenge themselves while expanding their horizons. For example, learners can access two new AI-powered features called Explain My Answer and Roleplay that are exclusive to Duolingo Max, a recent subscription tier that uses GPT-4 technology.

Duolingo also applies principles from learning theory and cognitive science to optimize educational outcomes. Spaced repetition and active recall are two key examples. The app uses spaced repetition to reinforce learning. This technique, based on cognitive psychology, involves revisiting material at increasing intervals to improve long-term retention and mastery. Duolingo’s exercises also often require users to actively recall information rather than passively review it. This active recall strengthens memory and enhances learning efficacy.

A large part of Duolingo’s success is due to the app’s ability to develop consumers’ interest and maintain or increase that interest over time. Its use of cognitive science and principles from learning theory make it an effective and extremely sticky language-learning app.

Results and Conclusion

So what has contributed to Duolingo’s staggering success? And how and why has this happened? Let’s back up and review before analyzing the results.

Duolingo has been exceptional in taking advantage of human psychology through specific methods/tactics:

1. Gamification
2. Behavioral Economics
3. Social Influence and Competition
4. Personalization and Communication
5. Cognitive Science

Delving deeper, Duolingo uses specific gamification mechanisms like badges and streaks which encourage, or pressure, users into sticking around and using the app. In fact, a study from 2021 found that 80% of language students enjoyed using Duolingo because of its gamification.

After introducing the achievement badges system, in-app purchases increased by 13% and the number of friends added also increased by a whopping 116%. Evidently, the added motivation led to more purchases and a stronger, more committed community. Additionally, with the streak system, thousands of users shared their achievements on social media daily, and there are 6 million people with a 7 day streak or more. This supports the claim that streaks help with user retention and motivation, as well as creating a more active social network through behavioral economics, social influence, and competition with peers and strangers around the world.

When measuring “success,” we are primarily looking for upward trends in user retention, revenue, and overall popularity in the market. As of Q2 2024, Duolingo has 34.1 million daily active users, an increase of 59% YoY, according to its 2024 Q2 SEC filings. Revenue is at $178.3 million, up 41% YoY from $126.8 million in Q2 2023. Paid subscribers totaled 8.0 million at quarter end, an increase of 52% from the prior year quarter. Duolingo’s user and revenue growth are due to its effective gamification mechanisms and its “stickiness” that give a reason for users to stick around–whilst attracting new users through its addictive nature with word of mouth referrals, social media sharing, and marketing campaigns.

Therefore, when we look at the question of “what made Duolingo so successful?” It is important to note their strategic use of psychology, behavioral, and cognitive science to not only pull new users in, but to keep them engaged and motivated to continue playing. The premium subscriptions/shop, streaks, and items such as hearts are all examples of how Duolingo can generate more revenue once they have new users “hooked.” Understanding how humans operate, think, and function is essential to maximizing a company’s performance financially. Duolingo exemplifies this and strategically executes this to perfection through methods like gamification and personalization. The results speak for themselves.

Now for the Scrimmage plug – we can build Duolingo’s engine for you!