N-Back
N-Back (Kirchner 1958) became a brain-training star after Jaeggi et al. (2008, PNAS) reported that adaptive dual N-Back training improved fluid intelligence. Measures continuous updating of working memory.
Intermediate: 2-back, 24 trials, 600ms + 2400ms ISI.
Squares light up one at a time on a 3×3 grid. If the current position matches the one 2 step(s) ago, press Match (or space).
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References: Jaeggi et al. (2008); Kane et al. (2007); Owen et al. (2005).
N-Back · scientific basis
N-Back (Kirchner 1958) became a brain-training star after Jaeggi et al. (2008, PNAS) reported fluid-intelligence gains from adaptive dual N-Back training. Owen et al. (2005) meta-analysis established its neural basis.
Expert-mode parameters
These are the standard parameters from the canonical paradigm (used by the "Expert" difficulty).
| Parameter | Standard value | Source |
|---|---|---|
| Stimulus duration (Expert) | 500 ms | Jaeggi 2008 |
| ISI | 2500 ms | Jaeggi 2008 |
| Trials per block | 20 + n | Jaeggi 2008 |
| Target ratio | ~30% (first 3 trials excluded) | Jaeggi 2008 |
Healthy-population norms (by age)
Age-stratified norms below apply to the **2-back** standard protocol (Jaeggi 2008); assessment mode picks the band matching your actual profile age. 1-back is easier (+0.5 d', +5% acc); 3-back is harder (−0.5 d', −5% acc). Working memory peaks at ages 18-34 and declines ~1 d' per two decades after that.
| Age band | d' excellent | d' good | accuracy mean | Evidence |
|---|---|---|---|---|
| Ages 8-9 | ≥ 1.8 | ≥ 1.3 | ~46% | medium-weak |
| Ages 10-11 | ≥ 2.1 | ≥ 1.5 | ~52% | medium-weak |
| Ages 12-13 | ≥ 2.4 | ≥ 1.8 | ~58% | medium-weak |
| Ages 14-15 | ≥ 2.6 | ≥ 2.0 | ~64% | weak (interp.) |
| Ages 16-17 | ≥ 2.8 | ≥ 2.2 | ~68% | weak (interp.) |
| Ages 18-24 | ≥ 3.0 | ≥ 2.35 | ~72% | strong |
| Ages 25-34 | ≥ 3.0 | ≥ 2.35 | ~72% | strong |
| Ages 35-44 | ≥ 2.9 | ≥ 2.25 | ~70% | medium |
| Ages 45-54 | ≥ 2.65 | ≥ 2.0 | ~66% | medium |
| Ages 55-64 | ≥ 2.4 | ≥ 1.75 | ~62% | medium |
| Ages 65+ | ≥ 2.1 | ≥ 1.45 | ~56% | medium |
Standard output metrics
- ·d-prime (d') — Signal-detection sensitivity; recommended primary
- ·Hit rate — Fraction of targets correctly flagged
- ·False-alarm rate — Fraction of non-targets incorrectly flagged
- ·Criterion C — Bias toward responding match
Citations
- Jaeggi, S. M., Buschkuehl, M., Jonides, J., & Perrig, W. J. (2008). Improving fluid intelligence with training on working memory. PNAS, 105(19), 6829-6833. DOI
- Kane, M. J., Conway, A. R. A., Miura, T. K., & Colflesh, G. J. H. (2007). Working memory, attention control, and the N-back task. J Exp Psychol LMC, 33(3), 615-622. DOI
- Owen, A. M., McMillan, K. M., Laird, A. R., & Bullmore, E. (2005). N-back working memory paradigm: A meta-analysis. Hum Brain Mapp, 25(1), 46-59. DOI
- Haatveit, B. C., et al. (2010). The validity of d prime as a working memory index. J Clin Exp Neuropsychol, 32(8), 871-880. DOI
All reference ranges come from published peer-reviewed literature. For personal training reference only — not a medical diagnosis. Full methodology: docs/PARADIGMS.md.
This tool is for educational and entertainment purposes only and does not constitute medical advice or a clinical diagnosis.