The learning algorithm
The learning algorithm allows learners to repeat the right content at the right time.
The learning algorithm of ovos play is based on the Leitner system according to Sebastian Leitner, who is known for systematic learning with flashcards. Learning takes place through staggered repetition: Content is repeated daily, every other day and every five days in order to achieve long-term retention in the memory.
Leitner's research is based on Ebbinghaus' forgetting curve, which states that what has been learned is forgotten after just a few hours:

This can be counteracted by repeating the content:

Note:
Neurodidactics has shown that connections are formed in the brain after just 20 minutes of training. If these are trained regularly, the information can be transferred from short-term to long-term memory.
Pro tips:
With the practice function learners can regularly repeat the content - 10 cards are always drawn from the card deck pool per session. The learning algorythm gives learners quiz questions that they have not answered for a while or have often answered incorrectly. This guarantees lasting learning and variety.
With the duel mode, learners can playfully compete against each other and thus acquire and consolidate knowledge through fun.
Duelling mode in ovos play:

This also promotes intrinsic motivation, i.e. the inner drive to want to do something. These three factors are important for this:
Autonomy: Learners can decide for themselves, e.g. the avatar or which deck of cards they start with.
Competence: Learners' abilities must be challenged - content must not be too easy or too difficult.
Connectedness: Learners need to feel connected to what they are doing.
Pro tip:
To keep motivation high, you can use playful elements such as the code card. You can use them for different content, e.g. to illustrate a process, ask for an important number or simply for fun 🙂
Code card:

Previous chapter: Use different media: image, audio, video and text
More information:
How does the learning algorithm work in ovos play?
Can points and progress measurements be individualized?
How does the "Code" card work?
Sources:
Sebastian Leitner (1972). So lernt man lernen: Der Weg zum Erfolg.
Grein, Marion (2013): Qualifiziert unterrichten: Neurodidaktik: Grundlagen für Sprachlehrende. Deutsch als Fremdsprache
Gamification Masterclass, hosted by Dr. Zac Fitz-Walter (2020)