Do streaks and rewards help

Gamification: what held up and what did not

Three different things need to be separated here. Do game mechanics help memorize the material — yes, noticeably. Do they add the desire to study — less so. Do they change behavior — less still.

Then it gets interesting. When the authors kept only the methodologically rigorous studies, the effect on learning held up; the ones on motivation and behavior did not. That is, the industry's most quoted claim — “gamification boosts motivation” — turned out to be the weakest spot of its evidence base.

What amplified the effect: combining a game narrative with people talking to each other, and competition with cooperation.

Rewards: measured harm

Over a hundred experiments tested the same thing: a person is given an interesting task and promised a reward for it, then left alone to see whether they take the task up by themselves once there is no reward. Here is what happened with a material reward promised in advance:

The reason is simple. While you study for yourself, it is your own business. As soon as they start paying for it, it becomes work. And when the payments stop, the reason to study disappears with the money.

• A material reward promised for doing a task lowers the wish to take it up of your own accord once the reward is gone. Praise for what was done, on the contrary, keeps that wish alive.checked many times
  Deci, Koestner & Ryan, 1999, Psychological Bulletin 125(6) · 128 experiments. A material reward promised in advance and the time later spent on the task by free choice: d = −0.44 for finishing, −0.40 for taking part, −0.28 for performance; a reward unrelated to the task, −0.14, not significant. Praise: +0.33.

Streaks: what we do not know and what can be guessed

Starting with the honest part: peer-reviewed trials of “streak versus no streak” in language apps do not exist. Figures like “streaks cut churn from 47% to 28%” come from corporate materials and were never independently verified.

But we can look at neighbouring data. A streak works like a reward for not quitting, plus the fear of losing it; and a reward promised for taking part, as shown above, lowers the wish to study of your own accord. And when researchers looked at what goes with success among language learners, it turned out that “I’d be ashamed to skip” and “I’ll get something for it” are barely linked to results. What is linked is “I find it interesting” and “I really need it”.

Plus the data on habits. A habit takes 66 days on average to form, with a range from 18 to 254: two and a half weeks for some people, more than eight months for others. And one missed day has no noticeable effect on its formation. A mechanic in which a missed day wipes out everything contradicts how habits actually form.

What this means for an app

• Show what accumulated, not what is unbroken: a miss should not zero out progress.
• Give feedback instead of rewards: “you recalled nine words out of ten” is exactly the kind of praise for what was done that keeps the wish alive.
• Don’t build everything on comparison with others: fear of making mistakes noticeably gets in the way of learning a language, and a leaderboard can fuel it.
• At the start ask not “what is your goal” but “when and where will you study”. The answer “after morning coffee, at the kitchen table” works; “study more” does not.

What this is based on

Every number above comes from a study, linked next to it. The mark “checked little” means one study stands behind the conclusion — or that researchers still argue about it.

• Games and points do help you take the material in. That they also add any desire to study rests on much thinner evidence than people assume.checked many times
  Sailer & Homner, 2020, Educational Psychology Review 32 · g = 0.49 for learning, 0.36 for motivation, 0.25 for behaviour. Among the most rigorous studies the effect on motivation did not hold up.
• A material reward promised for doing a task lowers the wish to take it up of your own accord once the reward is gone. Praise for what was done, on the contrary, keeps that wish alive.checked many times
  Deci, Koestner & Ryan, 1999, Psychological Bulletin 125(6) · 128 experiments. A material reward promised in advance and the time later spent on the task by free choice: d = −0.44 for finishing, −0.40 for taking part, −0.28 for performance; a reward unrelated to the task, −0.14, not significant. Praise: +0.33.
• The most successful learners are the ones who find it interesting or genuinely need the language. “I’d be ashamed to quit” and “there is something in it for me” are barely linked to success.checked many times
  Alamer et al., 2025, Educational Psychology Review · Correlation with success: interest and importance r = 0.23; guilt −0.06; external reward −0.01.
• A habit takes about two months to settle on average: two and a half weeks for some people, more than eight months for others. One missed day does not noticeably set it back.checked little
  Lally et al., 2010, European Journal of Social Psychology 40(6) · 66 days on average, ranging from 18 to 254. Missing a single day had no noticeable effect on habit formation.
• Deciding exactly when and where helps more than deciding to study at all. “After my morning coffee, in the kitchen, ten minutes” works; “I really should get to it” does not.checked many times
  Gollwitzer & Sheeran, 2006, Advances in Experimental Social Psychology 38 · 94 trials, more than 8,000 participants, d = 0.65.

Next

• Why a word list doesn't stickWhy rereading a word list barely works, what helps instead, and when to return to a word so it stays. With a walkthrough of the research.
• How many words you need to knowHow many words to learn to understand a conversation, and how many to read without a dictionary. And why “I know almost all the words” does not yet mean “I understood everything”.
• Is it too late to start as an adultWhat is known about the critical period: the data on 669 thousand people, the criticism of it, and what it means for an adult starting a language from scratch.
• How to break down an unfamiliar scriptA practical order for taking on an unfamiliar script: how many characters at a time, why to come back, why you must not start with words, and what to do about look-alike characters.