Humans Overlook Subtraction. So Does AI.

Ever notice that every time you ask AI to improve something, it adds content?

When it edits an email, it adds a new paragraph. If you ask it to edit a Slack message, it adds more words. It improves your apps by adding more features, more refinements.

It reminds me of the 2021 article in Nature titled “People systematically overlook subtractive changes.” When you ask people to improve something, they often don’t consider removing things. Subtractive changes just don’t occur to most people. The researchers even found that telling people to “improve” something made the bias worse.

Then I found a paper in 2024 that tested if AI inherits the human bias toward additive changes. It does.

So what I’ve been thinking about is this.

When you ask AI to edit a Slack message, it will polish it beautifully. But it’ll never come back and say, “should you even send this?”

AI seems to operate inside the task. It never questions the task.

Building things got so cheap that we stopped asking whether the thing should exist in the first place. The effort used to be the filter. When making something costs you time and cognitive load, the effort itself forced the question — is this even worth it? Take the cost away and the question never comes up.

And your LLM won’t volunteer it either. It inherits the same human bias.

So the skill that seems to be in short supply today isn’t using AI. Most of us are already doing that. It’s the question that AI will never ask.

Not “how do I make this better.” It’s “should this thing exist at all?”