"Cognitive debt" happens to developers using AI for coding: Dumbing down via AI use starts within weeks

[highplainsdem]

Bluesky post from Simon Willison, who is very much pro-AI:

Short musings on "cognitive debt" - I'm seeing this in my own work, where excessive unreviewed AI-generated code leads me to lose a firm mental model of what I've built, which then makes it harder to confidently make future decisions simonwillison.net/2026/Feb/15/...

— Simon Willison (@simonwillison.net) 2026-02-15T05:22:07.330Z

From his blog:

https://simonwillison.net/2026/Feb/15/cognitive-debt/

How Generative and Agentic AI Shift Concern from Technical Debt to Cognitive Debt (via) This piece by Margaret-Anne Storey is the best explanation of the term cognitive debt I've seen so far.

Cognitive debt, a term gaining traction recently, instead communicates the notion that the debt compounded from going fast lives in the brains of the developers and affects their lived experiences and abilities to “go fast” or to make changes. Even if AI agents produce code that could be easy to understand, the humans involved may have simply lost the plot and may not understand what the program is supposed to do, how their intentions were implemented, or how to possibly change it.

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I've experienced this myself on some of my more ambitious vibe-code-adjacent projects. I've been experimenting with prompting entire new features into existence without reviewing their implementations and, while it works surprisingly well, I've found myself getting lost in my own projects.

I no longer have a firm mental model of what they can do and how they work, which means each additional feature becomes harder to reason about, eventually leading me to lose the ability to make confident decisions about where to go next.

From Margaret-Anne Storey's blog:

https://margaretstorey.com/blog/2026/02/09/cognitive-debt/

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I saw this dynamic play out vividly in an entrepreneurship course I taught recently. Student teams were building software products over the semester, moving quickly to ship features and meet milestones. But by weeks 7 or 8, one team hit a wall. They could no longer make even simple changes without breaking something unexpected. When I met with them, the team initially blamed technical debt: messy code, poor architecture, hurried implementations. But as we dug deeper, the real problem emerged: no one on the team could explain why certain design decisions had been made or how different parts of the system were supposed to work together. The code might have been messy, but the bigger issue was that the theory of the system, their shared understanding, had fragmented or disappeared entirely. They had accumulated cognitive debt faster than technical debt, and it paralyzed them.

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But what can teams do concretely as AI and agents become more prevalent? First, they may need to recognize that velocity without understanding is not sustainable. Teams should establish cognitive debt mitigation strategies. For example, they may wish to require that at least one human on the team fully understands each AI-generated change before it ships, document not just what changed but why, and create regular checkpoints where the team rebuilds shared understanding through code reviews, retrospectives, or knowledge-sharing sessions.

Second, we need better ways to detect cognitive debt before it becomes crippling. Warning signs include: team members hesitating to make changes for fear of unintended consequences, increased reliance on “tribal knowledge” held by just one or two people, or a growing sense that the system is becoming a black box. These may be signals that the shared theory is eroding.

Finally, this phenomenon demands serious research attention. How do we measure cognitive debt? What practices are most effective at preventing or reducing it in AI-augmented development environments? How does cognitive debt scale across distributed teams or open-source projects where the “theory” must be reconstructed by newcomers? As generative and agentic AI reshape how software is built, understanding and managing cognitive debt may be one of the most important challenges our field faces.

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At least some developers have finally realized that they are being dumbed down by AI, with cognitive debt being added to the technical debt problem, which I first posted about on DU months ago - https://www.democraticunderground.com/100220891592 - but had seen software engineer Grady Booch posting about well before that.

And I've mentioned, again and again, how using AI dumbs people down in almost every way it's relied on - something teachers had noticed very quickly, of course, after OpenAI's Sam Altman made his unilateral decision to release ChatGPT in late 2022, when it instantly became a favorite cheating tool with students too uneducated to notice how much that flawed tool inevitably got wrong. Using AI makes people forget what they knew, in the same way lack of exercise weakens muscles. AI deskills people. And that's in addition to people who are planning to rely on AI never acquiring skills in the first place.

Scientific studies, even from Microsoft, backed up the obvious anecdotal evidence that people using AI were being dumbed down.

But it still seemed quite useful, especially for coding.

Even though evidence was piling up that it didn't help nearly as much as AI users thought it was helping with coding. That developers were often greatly overestimating time saved.

And now there's finally recognition of how much AI dumbs down people who are using it for coding.

Unfortunately that's after it's been used for a lot of coding, adding technical debt as well as a lot of security risks to code around the world.

As I've said before, generative AI is not only the most harmful non-weapon tech ever developed, it's also the stupidest.

And trillions are being wasted on it because of hype from AI robber barons who think their theft of the world's intellectual property to train a type of AI that they'll never get to stop hallucinating will soon lead to superintelligent AI that they hope will reward them by helping them take over the world, and giving them godlike powers including immortality.