The Science Behind the Four Minutes
Every Keel test is adapted from validated cognitive assessments used in research and clinical settings. Here is the full explanation: what each test measures, why those domains matter, how your baseline is calculated, and how to interpret what you see.
The five tests
Each test, the domain it measures, and its validated research basis.
The Symbol-Digit Test: Processing Speed, Explained
The symbol-digit coding task is one of the most replicated measures in cognitive neuroscience. Here is what it measures, why, and what your score actually tells you.
The Spatial Memory Test: Visuospatial Working Memory, Explained
Keel's spatial memory test probes the hippocampus and parietal cortex — two regions involved early in Alzheimer's pathology. Here is what it measures and why spatial memory matters.
The Semantic Fluency Test: Language and Executive Function, Explained
Naming as many items in a category as you can in 60 seconds sounds simple. The neuroscience behind why it is one of the most diagnostically informative tasks in clinical practice is not.
The Reaction Time Test: Processing Speed and Attention, Explained
Simple reaction time is one of the oldest measures in experimental psychology — and one of the most sensitive indicators of neurological integrity. Here is why milliseconds matter.
The Sequence Memory Test: Working Memory, Explained
Working memory is the cognitive workspace where you hold and manipulate information right now. Here is how Keel measures it, what the research shows, and why it matters for long-term brain health.
How your data works
Baseline calculation, trend interpretation, practice effects, and reading your results honestly.
How We Calculate Your Baseline
Your Keel baseline is not a score relative to other people. It is a statistical model of your own cognitive performance over time. Here is how it works.
What Your Trend Line Means
Your Keel trend line is the most important thing the app shows you. Not any single score. Here is how to read it, what patterns matter, and what does not.
Why Four Minutes? The Case for Brief, Daily Assessment
Longer tests produce richer single-session data. But daily compliance with a long test is nearly zero. Here is the science behind why four minutes, every day, is better.
Practice Effects: Why Your Early Scores Go Up (And Why That is Not Cheating)
When you start using Keel, your scores improve for the first few weeks. This is not your brain getting smarter — it is a well-understood phenomenon in cognitive assessment. Here is what it is and how Keel handles it.
Bad Days vs. Real Changes: How to Tell the Difference
Not every dip in your Keel scores means something. Most do not. Here is a framework for understanding the difference between noise, reversible effects, and trends worth attention.
See the tests for yourself
No account required. Four minutes, five tests. The first session gives you a feel for what Keel measures and how.
Free to start. No account required. Not a diagnostic tool.