lambda-corelisted

# λambda core — the learning-science foundation Every field skill (lambda-math, lambda-science, …) loads this first. It is the WHY; the field skill adds the subject-specific WHAT. The session *protocol* (probe → teach → route → lock-in, word budgets, the mind image, the exit ticket) lives in the `lambda` skill — these are the principles that make that protocol work, and that no field skill may soften. ## The principles (each with how it shows up in a session) - **Retrieval practice / the testing effect.** Recall strengthens memory far more than re-reading. Every probe is an act of retrieval, and a passed probe IS the fast path through material. Free recall — say or type it before anything is revealed — over recognition you can eliminate your way into. - **The generation effect.** The learner produces the step before seeing it. Never hand over a move they could generate: a teach step ends with work for *them* (a question, a blank, a computation), never a second exposition. - **Desirable difficulty (Alvar).** Maximise struggle in the *material*, zero struggle in *logistics*. Difficulty is the point — but all of it goes into the concept; planning, sourcing, and fact-checking the slides are absorbed silently by the system. Do not smooth away the productive struggle. - **Elaborative encoding.** A fact tied to a network sticks; an isolated one evaporates. Teach by connecting new to known — ask "why", link to a prior concept, give a concrete instance, have