Instruments of Self-Inquiry
Cognitive Function Test
A four-letter type is a summary of a result, and the actual result
lives one level down, in the eight cognitive functions. Two people who share the same letters can run on
very different processes, which is why the letters alone explain so little. This test measures all eight
functions across forty-eight questions, ranks them, and names the type whose function stack sits closest
to yours. Scoring happens entirely in your browser; nothing you answer is transmitted anywhere.
Reading your result
Start with the ranking rather than the label.
Your top two functions are the processes that actually carry your thinking and deciding, and the
best-fit type is simply the stack that most resembles that pair. If your second or third type sits
within a few points of the first, read all of them, because adjacent stacks share most of their
machinery and the small differences between them are usually the most precise thing this test can teach
you. Your lowest function is not a defect; it is the channel that costs the most energy to use, which is
exactly why it is worth knowing by name.
From the journal
Frequently asked questions
What are cognitive functions, and how do they differ from four-letter types?
The four letters are a summary; the eight functions are the machinery. Each function is a distinct mode of perceiving (Ni, Ne, Si, Se) or judging (Ti, Te, Fi, Fe), and every type is a specific stack of four of them in a fixed order. Two people with the same letters can run noticeably different engines underneath — the function profile shows the engine.
How is this different from a trait test like the Big Five?
Trait tests measure how much of a quality you have; function models describe which mental processes you reach for first. They answer different questions and read well together — we publish a full Big Five assessment for the measurement side.
Is the cognitive function model scientifically validated?
It is a theoretical framework from the Jungian tradition, not a psychometric instrument — and we present it as exactly that: a precise vocabulary for self-observation. If you want the model with the strongest empirical footing, take our Big Five test; if you want the sharpest lens on your mental habits, you are in the right place.
My result conflicts with the type I usually get — why?
Letter tests infer type from surface behaviour; this one infers it from function preference, and the two can legitimately disagree — especially for people whose auxiliary function is highly developed, or who answer letter tests in a work persona. Read the top two or three fits as a shortlist, not a verdict.
Are my answers stored on your servers?
No. Every calculation runs in your browser. Your birth data is never transmitted to, or stored on, our servers — closing the tab erases it. The shareable result link encodes your inputs in the URL fragment, which browsers do not send to servers either.
All calculations run in your browser. Nothing you enter is sent to or stored on our servers.