AI still doesn't write like you do. Here's proof-and how to use it
December 19, 2025
A new peer-reviewed study from University College Cork makes something clear: AI can write clean, fluent sentences, but its style is narrow and predictable. Human prose shows far more range-voice, rhythm, and choices that reflect lived experience.
The research used literary stylometry-the same computational methods used to study authorship-to compare hundreds of human short stories with outputs from models like GPT-3.5, GPT-4, and Llama 70B. The result: AI clusters tightly as a uniform style. Human work spreads out with variety.
What the study found
- AI models produce compact and consistent stylistic patterns across texts. GPT-4 is even more consistent than GPT-3.5.
- Human writing displays wider variation in function words, rhythm, and structural choices-markers of personal voice.
- AI sometimes comes close to human style, but those cases are rare when you zoom out across many samples.
As the lead researcher put it: "While AI writing is often polished and coherent, it tends to show more uniformity in word choice and rhythm. In contrast, human writing remains more varied and idiosyncratic, reflecting individual habits, preferences and creative choices."
And even when AI tries to mimic people: "its writing still carries a detectable fingerprint."
The work appears in Humanities and Social Sciences Communications. You can read the study here.
Why this matters for working writers
- Clients will use AI for drafts and summaries. Your edge is voice, insight, and decisions a model won't risk.
- Uniform style is easy to replace. Distinct style is hard to copy and easier to sell.
- This isn't about writing "like a human." It's about writing like you-consistently, and with range.
How to make your voice unmistakably human
- Vary rhythm on purpose. Mix short lines with long, layered sentences. Let cadence carry meaning.
- Use precise, lived details. Write from memory and observation, not clichés or stock phrases.
- Make specific, sometimes strange choices. Unusual verbs. Concrete metaphors. Hard edges over generic smoothness.
- Set constraints. Write a piece with only one rhetorical device, or ban three overused words you default to.
- Leave a fingerprint. Add one opinion per section that a committee would remove.
- Edit like a pro. Keep the structure tight, but don't sand off everything that makes it yours.
Where stylometry fits (and doesn't)
The researchers warn against using stylometry to police student work or judge authorship in education-it's unreliable and ethically questionable in that context. But it's useful for understanding broad stylistic patterns at scale, which helps explain why AI still reads differently, even when it feels close.
What AI is good for-and where you should step in
- Good for: outlines, rewrites for clarity, idea lists, sensitivity checks, quick summaries.
- Your job: narrative decisions, fresh angles, emotional truth, surprising structure, and a voice people remember.
As one university leader noted, AI's influence is growing fast. The practical move for writers is to use the tools for leverage while doubling down on the parts that make your work irreplaceable.
Next steps
- Audit your last five pieces. Where do you sound generic? Mark every sentence that could come from anyone.
- Create a "voice rulebook" for yourself: favored rhythms, banned phrases, signature moves, and a checklist for final edits.
- Use AI as a sparring partner, not a ghostwriter. Generate options, then rewrite 80% in your voice.
If you want curated tool lists and practical workflows without losing your voice, explore these resources:
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