What Is AI Writing?

AI writing is text generated by a large language model. It has consistent, recognizable patterns. Here's what it looks like and why it's different from human writing.

What AI Writing Actually Is

AI writing is text produced by a large language model (LLM) — a neural network trained on billions of words of human text. The model predicts the most likely next token given what came before. It doesn't think, reason, or have opinions. It produces statistically likely continuations of text.

This process creates characteristic patterns. The model learned from human writing — but it learned the average of human writing, not any individual voice. The result is text that sounds fluent but has specific tells.

Three Types of AI Writing

Academic AI

ChatGPT, Claude, Gemini writing essays, reports, summaries. Characterized by formal structure, vocabulary spikes, transition addiction, closing rituals. The most detectable type — AI defaults to academic register even when not asked.

Detection rate: 75–90%

Narrative AI

AI writing stories, creative fiction, social media posts. Characterized by phrase loops, subject monotony, semantic circularity. Harder to detect than academic AI but has its own distinct tells.

Detection rate: 65–80%

Humanized AI

AI text run through a humanizer tool (Undetectable AI, QuillBot). Vocabulary swapped, sentence structure varied. Phrase loops and transition persistence often survive. Hardest to detect.

Detection rate: 50–65%

7 Signs of AI Writing Anyone Can Spot

  1. Vocabulary spikes — "delve", "meticulous", "nuanced", "tapestry", "pivotal". If a text has 3+ of these in 500 words, that's unusual.
  2. Transition addiction — "Furthermore", "Moreover", "Additionally", "Consequently" every paragraph. Human writers use "also", "but", "so".
  3. Perfect structure — Every paragraph is 60–80 words. Every section has exactly the right number of points. No messiness, no digression.
  4. Closing ritual — "In conclusion, this essay has demonstrated..." followed by a summary of everything. Human writing ends more abruptly.
  5. No personal opinions — AI presents balanced perspectives but never commits. "On one hand... on the other hand... ultimately it depends."
  6. No factual errors — Human writers misremember dates, names, and details. AI is eerily accurate on common facts (though it hallucinates on obscure ones).
  7. Completeness — AI covers every angle of a topic. Human writers focus on what interests them and skip the rest.

AI Writing vs Human Writing — Quick Examples

AI WRITING

"Climate change represents a pivotal challenge that demands immediate attention. It is worth noting that the multifaceted nature of this issue requires a comprehensive approach. Furthermore, the nuanced interplay between economic and environmental factors cannot be understated. In conclusion, addressing climate change requires collective action."

HUMAN WRITING

"I started paying attention to climate change when I noticed the lake near my house was three feet lower than it was when I was a kid. That's not an argument — it's just what made it real for me. The politics of it don't interest me much. The water level does."

The human example has: a personal observation, an incomplete thought ("that's not an argument"), a digression, and an abrupt end. The AI example has: 4 vocabulary markers (highlighted), a transition, a significance marker, and a closing ritual.

How Different AI Models Write

ChatGPT — formal, structured, vocabulary-heavy Claude — epistemic hedging, careful qualifications Gemini — encyclopedic, factual, citation-like Grok — casual with depth, dry humor Copilot — action-oriented, instructional

Despite these style differences, all five share the universal AI patterns — vocabulary spikes, low burstiness, transition density — because they were all trained on similar human text data.