The original test

The Braverman test, explained

A 315-question test from a 2005 book sorts people into dopamine, acetylcholine, GABA and serotonin types. Here is how it works, why people find it compelling, and which parts survive contact with the evidence.

7 min readUpdated 2026-09-16

The Braverman Nature Assessment — usually just "the Braverman test" — comes from Eric R. Braverman's 2005 book The Edge Effect.1 It asks 315 true/false questions and tells you two things: which of four brain chemicals is your dominant nature, and which ones you are deficient in.

It's had a long life online because the premise is appealing and the output is specific. This page covers what it actually measures, the exact scoring rules (people mostly arrive looking for those), and what the research says about each of its claims.

How it's structured

Two parts, four groups each.

Part 1 — dominant nature. 200 questions, 50 per chemical, answered for how you are most of the time. Each group is organised into Memory and Attention, Physical, Personality, and Character sections, though those subsections aren't scored separately.

Part 2 — deficiencies. 115 questions answered for how you feel right now: 25 each for dopamine, acetylcholine and serotonin, and 40 for GABA.

The scoring rules, in full

Every TRUE is worth one point to its group. There is no reverse scoring and no weighting.

Part 1. Count the TRUE answers in each group. The highest is your dominant nature.

• Ties go to whichever comes first in the order dopamine → acetylcholine → GABA → serotonin. So a tie between dopamine and acetylcholine is scored as dopamine.2
• 35 or more in one group is what Braverman calls classically dominant, which he says suggests a less-than-balanced life.
• Any other nature scoring 10–15 points or more below your dominant one is described as a lifelong relative deficiency.

Part 2. Count the TRUE answers in each group and circle the highest — that's your most deficient nature, and the book says to address it first.

Which version you have

If you've found different copies with different question counts, they are genuinely different, and the differences matter more than they look.

• The book version has 315 items.
• The main online version has 314 — it drops one acetylcholine deficiency item.
• The paid report version drops another, and asks the Character section before Personality.
• One site's FAQ claims the complete test is 321 questions. No version I have been able to inspect contains 321 items, and the online versions contain fewer than the book, not more.

More consequentially, the online versions contain transcription errors that change meaning. "I have trouble getting out of bed" appears as "I have little trouble getting out of bed", which reverses it. A serotonin item reading "I have very low blood pressure" became "I have low blood pressure", making it identical to a GABA item — so one answer now counts toward two natures.

What the test gets right

It would be easy to dismiss the whole thing, and that would be wrong.

Two structural choices are genuinely good. Separating how you generally are from how you feel right now matches what the evidence shows: traits are relatively stable and only weakly tied to brain chemistry, while current states are changeable and much more strongly tied to it. And giving people a result that implies an action is why anyone takes a test at all.

What the research actually supports

Taking the four natures one at a time.

Dopamine is the one that survives closest to intact. Dopamine is well established in reward, effort and exploration: dopamine agonists given for Parkinson's disease cause impulse-control disorders in roughly 17% of the patients taking them — two to three times the rate in patients who aren't,3 and dopamine responsivity predicts willingness to work for a reward.4 But the trait it maps onto is exploration and drive, not the "rational, tough-minded, achievement-oriented" character the book describes.

Serotonin is inverted. The book describes serotonin types as impulsive, thrill-seeking and living in the moment. The research points the other way: serotonin tracks constraint. Lowering serotonin increases aggression and impulsivity,5 and cortical 5-HT2A binding is associated with the inward, anxious facets of neuroticism.6 Thrill-seeking belongs to dopamine.

GABA has no validated personality trait behind it. The book's GABA nature — stable, dutiful, organised, roughly half the population — doesn't correspond to anything measurable. GABA research concerns anxiety and cortical excitability, which is closer to the book's deficiency checklist than its personality type.

Acetylcholine has none either. The book describes acetylcholine types as creative, intuitive and romantic. The one brain-imaging finding linking the cholinergic system to a personality trait points to higher harm avoidance — anxiety-proneness — which is close to the opposite.

The deeper problem: no questionnaire can do this

Set the four natures aside. There is a more basic issue.

There is no validated way to measure brain neurotransmitter levels in a living person, and certainly not with a questionnaire.7 Blood and urine tests don't reflect brain levels. The causal evidence runs in one direction only: change someone's chemistry with a drug and you reliably change their behaviour. That is not the same as observing behaviour and inferring the chemistry.

And even if you could measure a level, the level may not be the variable that matters — controlled experiments find that people with identical hormone levels can have opposite responses.

I could find no published study of the Braverman assessment's reliability or validity: no internal consistency figures, no test-retest data, no factor analysis, and no comparison against any biological measure. Braverman's own published research is on brain electrical activity and dopamine genes,8 9 and none of it tests this questionnaire.

Where the field actually went

Psychology did not abandon the idea that biology shapes personality. It went somewhere more careful, in two directions.

Traits are dimensions, not types. A meta-analysis of more than 300 taxometric findings, across roughly half a million people, found dimensional models outnumbering categorical ones by about five to one — with the categorical results concentrated in the weaker studies.10 The HiTOP consortium's position is blunter still: no common mental disorder has ever been empirically verified as a discrete category.11 Sorting people into four natures is the wrong shape from the start.

The checkable differences are elsewhere. The physical differences that do reliably shape behaviour tend to be ones you can actually test: circadian phase, iron status, thyroid function, sleep apnea, medication effects. None of them are neurotransmitter natures, and all of them have a confirmation route — which is the thing a questionnaire result never has.

If you came for your result

You can still score the test with the rules above; they're accurate to the book. What the score won't tell you is anything about your neurotransmitters.

If you want the version of this that keeps the honest parts — the trait/state split, the sense that biology matters, a result that implies something — that's what this test is. It measures nine dimensions instead of four types, grades every biological claim by how good the evidence is, refuses to give you a percentile it hasn't earned, and says plainly what hasn't been checked about it.