Steps Back

Working-memory exercise, a spatial n-back. Stones light up one at a time. Say whether each one is the same stone as one, two or three steps back.

How it works

Nine stones sit in a three by three grid. One lights for a second, then the grid goes quiet, and three seconds after it lit the next one lights. For each stone you answer one question: is it the same stone as the one a set number of steps back? At level 1 that is one step back, the stone just before. Level 2 asks for two steps back and level 4 for three. The first few stones of a round are only to watch, since there is nothing yet to compare them with.

Tap Same spot or Different spot before the next stone lights. A round has twenty answered steps; six of them are matches. If no answer arrives before the next stone, that step counts as wrong, so a quick best guess is better than waiting.

Levels 3 and 5 add near misses: a stone that matches the step just before or just after the one you are tracking. Those are different, and they are what make the exercise about updating what you hold rather than a feeling of having seen it recently.

Read the in-game instructions before beginning. You can return home between exercises; there is no requirement to finish all six in one visit.

Understanding your result

The score is the average of two rates: matches you caught, and different stones you correctly passed. Answering Same every time, or never answering, scores 50, not higher. A score of 85 or more moves you up a level; under 55 moves you down one.

The n-back is a well-studied laboratory task. Practising it reliably makes people better at the n-back and at close relatives of it. The claim that it raises general intelligence or everyday memory did not hold up in larger follow-up studies. Treat your score as performance on this task.

Practice effects in a game do not by themselves prove improvement in everyday memory or prevention of cognitive decline. If you are concerned about a change in memory, speak with a qualified health professional.

Cost and saved progress

This exercise is free. It runs in a modern browser, requires JavaScript, and has no sign-up. Your saved game progress remains on this device in this browser. Clearing browser data can remove it.

Choose another memory exercise or learn about limbr.