Dual N-Back · Guides
Stroop test: the colour rule and a worked comparison
Recognise congruent and incongruent colour words, calculate a fictional response-time difference and read it with accuracy and protocol limits.
In this guide5
Respond to the ink colour
If the word RED appears in blue ink, the colour response is blue. Read the instructions first: a task asking for the written word uses a different rule. Stroop is the name of a family of experimental tasks, not a diagnosis from a phone game.
Distinguish the trial types
A congruent trial has matching word and ink, such as BLUE in blue ink. An incongruent trial combines different word and ink, such as RED in blue ink. Keep those labels consistent when comparing results. A neutral comparison condition, if present, is a separate category.
A fictional response-time difference
Imagine correct congruent responses average 600 ms and correct incongruent responses average 760 ms under the same protocol. The difference is 760 − 600 = 160 ms. These numbers are invented for the calculation; 160 ms is not a normal score, a personal target or an estimate of your attention.
Read the difference with the protocol
Record errors in each condition and the rule used to summarise time. The proportion of trial types, response method and comparison condition can affect interpretation. A congruent–incongruent difference combines the effects relative to those two conditions; it does not isolate a single mental process.
Keep practice and broader claims separate
Practice can change performance on a familiar task. That observation alone does not establish reduced impulsivity or improved attention in daily life. Keep the device and task comparable, and do not use the result to diagnose an attention or memory disorder.
Questions
Is a 160 ms Stroop difference normal?
This guide uses invented averages of 600 and 760 ms to explain subtraction. The resulting 160 ms is not a norm, diagnostic threshold or target.
Does practice prove improved everyday attention?
A change on a familiar Stroop task does not by itself demonstrate improved attention or reduced impulsivity in daily life.
What should I compare alongside response times?
Keep errors, trial types, response rules and device conditions visible. Different comparison conditions can change the meaning of the time difference.
Further reading
- Stroop (1935), Studies of interference in serial verbal reactions, Journal of Experimental Psychology
- MacLeod (1991), Half a century of research on the Stroop effect: an integrative review, Psychological Bulletin
- Deary, Der & Ford (2001), Reaction times and intelligence differences: a population-based cohort study, Intelligence
- Jaeggi et al. (2010), The relationship between n-back performance and matrix reasoning, Intelligence
Guides
How to play dual n-back: a clear first session
Understand position matches, sound matches and the meaning of N before your first dual n-back session.
Dual N-Back settings on iPhone: audio, feedback and levels
Understand audio, feedback, N-levels, progression locks and session length with an annotated screenshot of the Dual N-Back iPhone app.
Dual n-back scoring: formulas, examples and calculator
Understand hits, misses and false alarms in dual n-back. Compare scoring formulas with a worked example and an interactive calculator.
Does dual n-back training work? What the evidence actually says
An honest walk through the research on dual n-back: what improves, what does not, why the meta-analyses disagree, and how to train without fooling yourself.