Learning science essentials

Why it matters

Most people teach the way they were taught: explain the topic clearly, show some slides, then move on. Learners nod along, the feedback forms say "great session", and a week later most of it is gone. Cognitive psychology has studied why this happens for more than a century, and it has found a few techniques that reliably make learning last. They are cheap, they work for beginners and experts, and almost every training course underuses them.

Throughout this course we follow one example: a 90-minute workshop that teaches new junior developers to use Git (commit, branch, merge and recover from mistakes).

Learning is changing long-term memory

A useful working definition: learning is a lasting change in long-term memory that lets someone do something they could not do before. Two consequences follow.

• Performance during the session is a poor guide. Learners who just watched you run git merge can copy it immediately. That does not mean they can do it next Tuesday on their own. Robert and Elizabeth Bjork call this the difference between performance and learning.
• Feeling fluent is not the same as knowing. Re-reading notes or watching a demo again feels easy, so learners (and trainers) think it is working. Psychologists call this an illusion of fluency.

Retrieval practice: make people pull information out

The testing effect is one of the best-replicated findings in learning science. In a well-known study, Henry Roediger and Jeffrey Karpicke (2006) had students read a passage and then either re-read it or take a recall test with no feedback. After five minutes the re-readers did slightly better. After one week the tested group remembered far more. Pulling an answer out of memory strengthens the memory itself; it is not just a measurement.

In practice, retrieval practice means low-stakes questions that make learners produce an answer:

• Start the session with three questions on last week's topic.
• After a demo, ask "write the command that creates a branch called fix-login" before showing it again.
• End with a one-minute "brain dump": write everything you remember about merging.

It works best when the questions are effortful but answerable, and when learners get the correct answer afterwards.

Spacing: spread practice out

Hermann Ebbinghaus measured his own forgetting in the 1880s and found that memories fade quickly at first and then more slowly: the forgetting curve. He also found that repetitions spread over days beat the same number crammed together. A large meta-analysis by Nicholas Cepeda and colleagues (2006) confirmed this spacing effect across hundreds of studies.

For the Git workshop, that means not teaching everything in one block and never mentioning it again. Instead:

Each return trip is a retrieval opportunity, so spacing and retrieval combine.

Interleaving and desirable difficulties

Interleaving means mixing different kinds of problems instead of practising one kind in a block. Doug Rohrer and Kelli Taylor (2007) found that students who practised mixed maths problems did worse during practice but much better on a later test, because they had to work out which method fits each problem. For Git, mix "undo the last commit", "switch branch" and "resolve a conflict" tasks rather than doing ten of each in a row.

Robert Bjork groups these techniques under desirable difficulties: conditions that slow learning down in the moment but improve long-term retention. The word desirable matters. A task so hard that learners cannot succeed at all is just frustrating.

What the evidence ranks highly

John Dunlosky and colleagues (2013) reviewed ten common study techniques. They rated practice testing and distributed (spaced) practice as high utility, and highlighting, re-reading and summarizing as low utility. This is a good shortlist to remember when you design anything.

Common mistakes

• Treating quizzes only as grading. Ungraded, frequent quizzes are a teaching tool.
• Ending with a recap you deliver. Ask learners to produce the recap instead.
• Judging success by the mood in the room. Smiling, nodding learners are not proof of learning. Check what they can do later.
• Massing everything into one day because the calendar is easier. Add at least one spaced follow-up.

Quick recap

• Learning is a lasting change in long-term memory, not good performance in the session.
• Retrieval practice: make learners recall, then give the answer.
• Spacing: return to material over days and weeks.
• Interleaving and other desirable difficulties feel harder but last longer.

Try it

Take a lesson you have taught or attended. On the Do tab, answer the quiz, then write down one retrieval question you could add at the start and one spaced follow-up you could schedule.