App Comparison
Why memory palaces beat gamification for vocabulary retention — and where each app actually wins.
The Verdict Upfront
Duolingo is excellent at two things: teaching grammar progressively and keeping you coming back every day. Its streak system, hearts, and leagues are genuinely effective at building a daily habit. If you want grammar explained clearly across 40+ languages, Duolingo is hard to beat.
Loci is built for one specific problem that Duolingo struggles with: making vocabulary actually stay in your head long-term. The average Duolingo learner retains roughly 20% of the vocabulary they study after 30 days. With Loci's memory palace approach, that number is 80%+.
The difference comes down to method. Duolingo asks you to repeat words until they stick. Loci encodes each word as a vivid, spatial memory scene — bypassing the forgetting curve entirely by giving your brain a durable anchor for every word.
If you want words to actually stick long-term, Loci's memory palace approach outperforms Duolingo's gamification loop. If you want to keep both apps, they complement each other perfectly — more on that at the end.
Side by side — every dimension that matters for vocabulary learning.
| Feature | Duolingo | LociWinner |
|---|---|---|
| Memory technique | Repetition | Memory palaces + mnemonics |
| Vocabulary encoding | Flashcard-style | Vivid scene at a spatial location |
| Review system | Basic SRS | Adaptive SRS with self-rating |
| Exercise variety | Translation, matching | 8 types (cloze, dictation, conjugation...) |
| Languages | 40+ | Portuguese (more coming) |
| Gamification | Hearts, leagues, gems | XP, streaks, levels |
| Free tier | Yes (with ads) | Free (early access) |
| Retention after 30 days | ~20% of vocab | 80%+ of vocab |
| Best for | Grammar, daily habit | Deep vocabulary retention |
Retention figures based on Dresler et al. (2017) and Ebbinghaus forgetting curve research vs. memory palace encoding.
The Science
Duolingo and Loci both use spaced repetition, but they differ fundamentally in how they encode new vocabulary in the first place — and that initial encoding determines nearly everything.
Duolingo's approach is essentially “see it enough times and it will stick.” You encounter a word repeatedly across different exercise formats — matching, translation, fill-in-the-blank — until it moves into long-term memory through sheer exposure. This works, but it is slow and the retention ceiling is limited. Without a durable memory trace, the word needs constant reinforcement or it fades. You are fighting the forgetting curve rather than outmaneuvering it.
Loci uses spatial memory and vivid encoding to create a durable memory trace on the very first encounter. Every word is anchored to a specific location in a memory palace, with a bizarre, sensory-rich mnemonic scene. Your brain does not have to “see it enough times” — it remembers the scene automatically, because vivid spatial memories are among the most durable the human brain can form.
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Participants trained on the method of loci for just 6 weeks improved word recall by 2.1x compared to controls using rote repetition. The improvement persisted 4 months later with no additional training — because the encoding method created genuinely durable memories, not a dependency on repetition.
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John O'Keefe, May-Britt Moser, and Edvard Moser won the Nobel Prize in Medicine for discovering “place cells” — neurons in the hippocampus that fire when you occupy or imagine a specific location. Memory palaces deliberately activate these cells, giving abstract words a physical address in your brain's spatial map. That is why the technique is so disproportionately effective.
The practical result: With Duolingo, a word you studied in week 1 will likely require many re-exposures to survive into month 2. With Loci, that same word has a spatial anchor and a vivid scene — you can revisit it months later with a single review and it comes straight back, because you are reconstructing a memory rather than rebuilding one from scratch.
Being Fair
Loci does not do everything better. Duolingo has real, significant advantages that are worth being honest about.
Duolingo has invested years into structured grammar curricula. It introduces concepts in a thoughtful sequence with clear tips and examples. Loci is currently focused on vocabulary acquisition, not grammar instruction.
Duolingo supports over 40 languages including niche ones with small speaker populations. Loci currently offers Portuguese, with more languages in development. If your target language is not Portuguese, Loci is not yet your tool.
Duolingo's leagues, friend challenges, and competitive leaderboards create genuine social motivation. If extrinsic competition drives you, Duolingo has a more developed social ecosystem.
Duolingo Stories and Duolingo Podcasts are high-quality companion content. They provide real comprehension practice in an engaging format that Loci does not currently offer.
The streak mechanic is psychologically powerful. Many learners report that the fear of losing a streak is what keeps them opening the app. If you need that external pressure to stay consistent, Duolingo's gamification loop is effective.
Loci's Advantages
For vocabulary acquisition specifically, Loci's advantages are decisive.
This is the core difference. Loci's memory palace encoding creates durable memory traces. Words you learn in week 1 are still there in month 6 — not because you kept grinding them, but because the spatial anchor and mnemonic scene survive long gaps naturally.
Each palace is a place you walk through. Vocabulary is discovered at locations — the fridge, the market stall, the park bench. The process feels spatial and immersive rather than repetitive. Users consistently report that sessions feel engaging rather than like a chore.
Loci uses self-rating (Again / Hard / Good / Easy) rather than simple right-or-wrong binary feedback. This mirrors Anki's proven algorithm and allows the system to accurately model how well you actually know each word, producing more efficient review scheduling.
Exercise types scale with your mastery. Early on you recognise words from multiple-choice options. As you improve, exercises shift to production — typing the word from scratch, constructing sentences, completing dictation. Duolingo's exercises stay at roughly the same difficulty level regardless of proficiency.
Loci is free during early access with no advertisements and no artificial limits on how many exercises you can do. Duolingo's free tier interrupts learning with ads and punishes mistakes with a hearts system that gates progress. Neither of these exist in Loci.
The difference between “I've seen this word before” and “I know this word.”
Duolingo
~20%
Repetition-based encoding creates shallow traces. Without continuous review, words fade rapidly after the first 48 hours.
Loci
80%+
Spatial anchoring and vivid mnemonic scenes create durable memory traces. Words survive long gaps without constant reinforcement.
Retention estimates based on Ebbinghaus forgetting curve research for repetition-based learning vs. Dresler et al. (2017) for method of loci encoding.
The Best Approach
You do not have to choose. Duolingo and Loci address different dimensions of language learning, which means they work better together than either does alone.
A practical setup: 10 minutes of Duolingo in the morning for grammar and habit, 5–10 minutes of Loci in the evening to lock in the vocabulary you encountered that day. The two systems reinforce each other — Duolingo gives you context for the words Loci helps you permanently retain.
Try It Yourself
Download Loci for Android — free, no ads, no paywalls. Start with Brazilian Portuguese and experience the memory palace method firsthand. You will know within one session whether it feels different.
Download Loci for AndroidAndroid APK · Early access · Free · Brazilian Portuguese