Five constitutional types describe how people are built.
Take the assessment. Read the framework. See yourself.
The framework descends from a 1921 work of constitutional psychology by Elsie Lincoln Benedict, modernised, stripped of the things that did not survive a century of scrutiny, and put on contemporary biological footing. It describes five orientations — Digestive, Circulatory, Muscular, Skeletal, Cerebral — each named for a body system and each pointing at a recognisable shape of attention.
The point is not to predict what people will do. The point is to notice, more carefully, what they are oriented toward. Held lightly, the framework gives a working vocabulary for the kind of difference between people that is otherwise inarticulate. Held heavily, it becomes a horoscope. The site is calibrated for the first reading, and warns against the second.
Most people are dominantly one type and secondarily another. The twenty-six-question assessment identifies both, with a confidence band, and produces a shareable URL. Nothing is stored on a server. The result is what the URL says it is.
Read the framework
The five-type structure, the dominant-secondary blending, what the framework claims and what it does not.
See the limits
The honest critique. Determinism is overstated, empirical validation is sparse, within-type variation is large.
Read the blends
The eight most defensible combinations. Engineer-founder, gentle systems thinker, master craftsperson, and others.
Three reasons this site exists.
Vocabulary. The framework gives words for orientations that otherwise live as inarticulate texture in the room. A Cerebral and a Digestive who have a vocabulary for what is different about them are more likely to stay friends and married than a Cerebral and a Digestive who do not.
Calibration of difference. Each type's vulnerabilities are real and observable in oneself once they have been named. The Cerebral who has been told they live above the neck knows what to look at on the day they have not slept well; the Muscular who has been told they push through one cycle too long knows what they are doing on the day their knee is bothering them again.
Honest framing. Personality frameworks degrade easily into horoscopes. This site refuses several of the moves that drive the degradation: each type page has a section on where the framework breaks down for that type; the assessment uses forced-choice rather than agree-or-disagree; the result includes secondary types and confidence bands rather than a single flattering verdict.