Six instruments.
Decades of validation.
BASLN does not invent new cognitive tests. It administers compressed digital versions of instruments spanning over 60 years of peer-reviewed research, from foundational 1958 studies to modern NASA-developed test batteries. This page explains each one and links to the primary sources.
Honest disclosure
The underlying tests are validated. BASLN's specific iOS implementation has not yet been formally validated against the gold-standard hardware. We plan to run that validation study on iOS. Until it's published, treat BASLN as a self-tracking tool built on research-grade tasks, not a clinical instrument.
- 01 · PVT-B
Psychomotor Vigilance Test (PVT-B)
Reaction time · Vigilance
Tap the moment a counter appears. No learning effect. The gold-standard measure of fatigue in sleep deprivation research.
Run on the ISS as the astronaut Reaction Self-Test. Used in thousands of peer-reviewed sleep studies.
Primary citation
Basner M, Mollicone D, Dinges DF (2011). Validity and sensitivity of a brief psychomotor vigilance test (PVT-B) to total and partial sleep deprivation. Acta Astronautica, 69(11–12), 949–959.
Read the paper → - 02 · 2-Back
Spatial 2-Back
Working memory
Watch a shape appear in one of 9 positions. Report when the current position matches the one two steps ago.
The spatial N-back paradigm is a canonical working-memory task, validated in neuroimaging work by Jonides et al. (1993). NASA's Cognition battery uses a fractal-identity variant for spaceflight research.
Primary citation
Jonides J, Smith EE, Koeppe RA, Awh E, Minoshima S, Mintun MA (1993). Spatial working memory in humans as revealed by PET. Nature, 363, 623–625.
Read the paper → - 03 · DSST
Digit Symbol Substitution (DSST)
Processing speed
Match digits to symbols as fast as possible against a reference key. The single best predictor of complex operational performance.
In NASA-funded research, DSST average response time explained 34% of the variance in simulated 6DF spacecraft docking performance.
Primary citation
Basner M, Moore TM, Hermosillo E, Nasrini J, Dinges DF, Gur RC, Johannes B (2020). Cognition Test Battery Performance is Associated with Simulated 6 DF Spacecraft Docking Performance. Aerospace Medicine and Human Performance, 91(11), 861–867.
Read the paper → - 04 · Stroop
Color-Word Stroop
Executive function · Inhibitory control
Identify the color a word is printed in, not the word itself. Measures your ability to override automatic responses.
One of the most validated executive-function instruments in experimental psychology.
Primary citation
MacLeod CM (1991). Half a century of research on the Stroop effect: an integrative review. Psychological Bulletin, 109(2), 163–203.
Read the paper → - 05 · Arithmetic
Arithmetic Verification
Processing speed under load
Verify whether simple equations are true or false, under time pressure. A compact proxy for cognitive throughput.
Serial addition / subtraction tasks have been a core component of operational cognitive batteries since the Walter Reed Performance Assessment Battery (WRPAB).
Primary citation
Thorne DR, Genser SG, Sing HC, Hegge FW (1985). The Walter Reed performance assessment battery. Neurobehavioral Toxicology and Teratology, 7(4), 415–418.
Read the paper → - 06 · TMT-B
Trail Making B
Cognitive flexibility · Task switching
Connect alternating numbers and letters as fast as possible. Measures the cost of switching rules on the fly.
Core measure in clinical neuropsychology since Reitan (1958).
Primary citation
Reitan RM (1958). Validity of the Trail Making Test as an indicator of organic brain damage. Perceptual and Motor Skills, 8, 271–276.
Read the paper →
On “measure vs. infer”
Consumer wearables measure HRV, sleep stages, and respiratory rate. They then apply proprietary composites to produce a “readiness” or “recovery” score. These scores are useful heuristics for autonomic state.
Autonomic state is not cognitive state. The correlations between HRV-derived readiness scores and actual cognitive performance have not been established at scale by independent researchers. BASLN does not argue wearables are wrong. It argues they are answering a different question.
If you want to know whether your reaction time is 80ms slower than yesterday, the only way to find out is to measure your reaction time.