One question before you start

Do you think human and AI writing became more similar over time?

Press a key.

Plot twist! Human and AI writing are not becoming more alike

We examine which words follow 72 common words like “the” and “and” in Reddit’s r/explainlikeimfive posts and ChatGPT conversations from WildChat, comparing each year’s patterns against a 2016–2026 Reddit baseline to track changes in sentence structure over time.

The measurement itself

Two lines that never meet

The gap, on its own scale

Source: Jensen–Shannon divergence across 72 seed words, with matched sample sizes and a pre-AI human reference. 90% intervals: ±0.004 — thinner than these lines are drawn.

Try it on a word

The Humanometer

Humanometer

Built from the data we collected, our Humanometer algorithm maps words along a human-to-AI spectrum based on how frequently each side uses them.

All fourteen at once

Every category we measured, on one wheel. Each spoke is scaled to whichever side uses it more, so the leader touches the rim and the other sits in proportion behind it.

Human AI numbers are the share of passages using that category

Between the Words

Each word is positioned by who uses it more: Reddit commenters on the right, Claude/WildChat on the left. Higher words appear more often across both corpora.

Let’s awaken your senses!

Select all squares with things that make you cringe

Human Senses

How often humans and AI use sensory language.

A cloud drawn against a blue sky, with the words: let your imagination wander
press enter

What people saw

Two gumball machines: a human head and a robot head

Imagination words
used 1.67× as often

Each machine holds the imagination words its own side actually uses, in its real proportions, and its crank turns once per word. Reddit reaches for imagination in 2.24% of passages against WildChat’s 1.34% — 1.67× as often.

Your friend’s having a bad day.
What’s your first move?

Pick one.

An open first aid bag

Help find a solution

0

Be there and listen

0

Empathy

Plot twist #2!

This graph counts words from a fixed empathy-related list, such as “empathy,” “compassion,” “sympathize,” “heartfelt,” etc. It measures their frequency, rather than how empathetic a response is.

Talking about empathy vs. showing it

Across 50 r/Advice posts answered by both humans and AI, how often do their replies express empathy, rather than simply recommend being empathetic?

Human AI

“The limits of my language mean the limits of my world.”

Ludwig Wittgenstein, Tractatus Logico-Philosophicus

Ori Shemer

Design Engineering

Zak Vaneck

Mechanical Engineering

Data

  • r/explainlikeimfive, 2016–2025 — the human side. 2016–17 pooled is the pre-AI reference.
  • WildChat, 2023–2025 — the AI side. Zhao et al., WildChat: 1M ChatGPT Interaction Logs in the Wild, arXiv:2405.01470.
  • r/Advice 2021 + AI answers written to the same 50 questions — the topic-matched test.
  • Frontiers in Psychology via PubMed Central, 2018–19 against 2025–26 — the same question asked of academic prose, where the genre holds still.

Background

  • Kosmyna et al., Your Brain on ChatGPT: Accumulation of Cognitive Debt when Using an AI Assistant for Essay Writing Task. MIT Media Lab, arXiv:2506.08872.
  • Yakura et al., Empirical Evidence of Large Language Model’s Influence on Human Spoken Communication. 2025.
  • Liang et al., The Widespread Adoption of LLM-Assisted Writing Across Society. arXiv:2502.09747.
  • Liu, Asymmetric Discourse Homogenization and Shared Language Technology: Evidence from Reddit. arXiv:2608.13674.