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One-Back Letters is the simplest n-back task: say whether each letter matches the one immediately before it. It exists as a stepping stone — the rolling-window habit is easy to learn at 1-back and hard to learn at 2-back, so starting here makes the harder versions accessible.
Letters appear one at a time at a fixed tempo.
Respond when a letter matches the one immediately before it.
Stay silent on non-matches.
Keep the tempo — the rhythm is part of the task.
Accuracy across the run is your score.
A game is 25 letters, one every two seconds. Letters that are easy to confuse with numbers (I and O) are left out, and about a third of letters repeat the one before.
Press Match (or Space) on a repeat to score 1. Pressing when it is not a repeat is a false alarm; a repeat you let pass is a missed match. Accuracy is matches divided by matches plus false alarms.
The updating habit itself: hold one item, compare, replace. It is the mechanism every higher n-back builds on, isolated to its simplest form. Another memory game to try next: Senior Memory.
1-back is the entry level of the n-back task that Wayne Kirchner introduced in 1958: respond when the current item is the same as the one just before it. It needs only one item in memory, but that item has to be replaced on every step.
Brain-imaging meta-analyses of n-back studies find the same frontal and parietal network active across versions, with activity increasing as N rises. 1-back is where the task is taught; once it is easy, 2-back is the step that genuinely loads working memory.
Hold exactly one letter and replace it every beat. Do not build a list.
Name the letter silently as it appears. The verbal tag makes the comparison automatic.
Do not press on every item. Silence is the answer most of the time.
If you find this easy, move to N-Color Back at 2-back rather than staying here.
As training, largely yes. As a way to learn the mechanic before attempting 2-back, it is genuinely useful.
Once you can run a full session at high accuracy without effort.
Same family, one stream and N of one. Dual N-Back runs two streams at N of two or more.
At high tempo the comparison has to complete before the next item arrives. That is the constraint the higher levels exploit.