The Ghostwriter
Method and sources
Each round deals ten passages, five written by people and five by a machine, drawn at random from a pool of 32. Because every round is balanced, guessing at random scores five, and that is the number each result is measured against. There is no clock. Each answer is quietly timed, because how fast you commit is how the result reads your confidence, but you can take as long as you like. Play again and the passages are ones you have not seen.
The human passages
All are verbatim, unedited text from works in the public domain in the United States — anything published in 1930 or earlier. Nothing here is quoted under a fair-use argument; these works belong to everybody. Each links to its full text so you can check us.
- William Shakespeare, Much Ado About Nothing (1599) Project Gutenberg
- Jane Austen, Pride and Prejudice (1813) Project Gutenberg
- Frederick Douglass, Narrative of the Life of Frederick Douglass (1845) Project Gutenberg
- Herman Melville, Moby-Dick (1851) Project Gutenberg
- Henry David Thoreau, Walden (1854) Project Gutenberg
- Joseph Conrad, Heart of Darkness (1899) Project Gutenberg
- W. E. B. Du Bois, The Souls of Black Folk (1903) Project Gutenberg
- G. K. Chesterton, Orthodoxy (1908) Project Gutenberg
Passages were chosen from the middle of each work and deliberately are not the lines those books are famous for. A study that rewards having recognised the opening of a novel measures your reading history, not your ear.
The machine passages
All 16 were generated by Claude (Opus 5) from a short register brief and nothing else. No passage above — and no other copyrighted or public-domain text — was supplied to the model as an example to imitate. Each brief names a register and a tone, never an author:
- elizabethan prose speech, aphoristic
- elizabethan prose speech, dismissive
- regency social novel, ironic narrator
- regency social novel, village gossip
- victorian maritime narrative, wry
- victorian field-naturalist notebook
- victorian moral essay, contrarian
- transcendentalist nature essay, plain moral turn
- transcendentalist nature essay, aphoristic
- edwardian paradox essay, conversational
- edwardian paradox essay, inverted commonplace
- early modernist fiction, interior
- early modernist fiction, elided
- colonial river narrative, retrospective
- victorian homily, admonitory
- victorian memoir, understated
One thing we chose not to do
Some of the human passages are by Frederick Douglass and W. E. B. Du Bois. We did not generate machine imitations of slave-narrative or early Black sociological prose to sit alongside them. Manufacturing counterfeit testimony of that kind as material for a guessing game is not something this study was willing to do. The machine half covers other registers of the same periods instead, and the deck stays balanced.
What this measures — and what it doesn't
It measures whether you can distinguish these particular passages, which are short, period-flavoured, and stripped of context. It does not measure whether you can spot AI in the writing you actually encounter — a work email, a report, a LinkedIn post. Modern functional prose is a different problem, and probably a harder one.
The result you are shown separates two things that usually get confused: how often you were right, and how often you were sure. Those turn out to be much less related than most people expect, and that gap is the finding this study is really after.
Participation is anonymous. Responses are used in aggregate only. Runs completed implausibly fast are excluded from the published averages. See the Privacy Policy.