Most training is built around watching and re-reading — the things that feel like learning but fade within weeks. Derry is built around what the evidence actually shows makes knowledge stick: effortful retrieval, spaced over time, mixed across skills. Here is the science, and exactly how the platform puts it to work.
The single most robust finding in the science of learning is the testing effect: the act of pulling an answer from memory strengthens that memory far more than reviewing the same material again. Effort is the point — retrieval that takes work produces durable learning.
Reviewing material at increasing intervals dramatically outperforms massed study ("cramming"). A little forgetting between sessions makes the next retrieval more effortful — and therefore more powerful. Crammed knowledge tests well tomorrow and is gone next month.
Practising one skill to exhaustion before moving on feels productive but teaches the pattern, not the judgement. Interleaving different problem types forces you to first work out which approach applies — the skill you actually need on the job.
Learning conditions that feel harder in the moment — retrieval, spacing, interleaving, varied practice — produce stronger, more flexible, longer-lasting learning. Conditions that feel smooth (re-reading, highlighting) produce fluency you mistake for mastery.
Knowledge sticks when you tie new ideas to what you already know and put them into your own words — and when you attempt a solution before being taught it. Generating an answer, even a wrong one, primes you to learn the right one.
Learners are poor judges of their own knowledge — fluency feels like competence. Reflection (what worked, what didn't) and calibration (rating your confidence and checking it against reality) close that gap and direct effort where it's needed.
The evidence is just as clear about what to stop doing.
| Feels like learning | What the evidence shows |
|---|---|
| Re-reading notes and highlighting | Produces fluency and false confidence, not durable memory. |
| Massed practice / cramming | Good for a test tomorrow; largely gone within weeks. |
| Watching lectures on repeat | Passive exposure without retrieval builds little lasting skill. |
| Blocking one skill until "done" | Teaches the procedure but not when to use it. |
Grounded in the cognitive-science of durable learning, summarised for a general audience in Make It Stick: The Science of Successful Learning (Brown, Roediger & McDaniel, 2014) and in the primary research on retrieval practice (Roediger & Karpicke, 2006), distributed practice (Cepeda et al., 2006), interleaving (Rohrer & Taylor, 2007) and desirable difficulties (Bjork). These describe how learning works in general; individual results depend on the effort you put in. Derry Training LLC.
