alt Hacker NewsMy grad school research was on computational models of human/machine cognition, and I'm now commercializing it as a 'proof-of-human API' for bot detection, spam reduction, and identity verification.
One of the mistakes people assume is that AI capability means humanness. If you know exactly where to look, you can start to identify differences between improving frontier models and human cognition.
One concrete example from a forthcoming blog post of mine:
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In fact, CAPTCHAs can still be effective if you know where to look.
We ran 75 trials -- 388 total attempts -- benchmarking three frontier AI agents against reCAPTCHA v2 image challenges. We looked across two categories: static, where each image grid is an individual target, and cross-tile challenges, where an object spans multiple tiles.
On static challenges, the agents performed respectably. Claude Sonnet 4.5 solved 47%. Gemini 2.5 Pro: 56%. GPT-5: 23%.
On cross-tile challenges: Claude scored 0%. Gemini: 2%. GPT-5: 1%.
In contrast, humans find cross-tile challenges easier than static ones. If you spot one tile that matches the target, your visual system follows the object into adjacent tiles automatically.
Agents find them nearly impossible. They evaluate each tile independently, produce perfectly rectangular selections, and fail on partial occlusion and boundary-spanning objects. They process the grid as nine separate classification problems. Humans process it as one scene.
The challenges hardest for humans -- ambiguous static grids where the target is small or unclear -- are easiest for agents. The challenges easiest for humans -- follow the object across tiles -- are hardest for agents. The difficulty curves are inverted. Not because agents are dumb, but because the two systems solve the problem with fundamentally different architectures.
Faking an output means producing the right answer. Faking a process means reverse-engineering the computational dynamics of a biological brain and reproducing them in real time. The first problem can be reduced to a machine learning classifier. The second is an unsolved scientific problem.
The standard objection is that any test can be defeated with sufficient incentive. But fraudsters weren't the ones who built the visual neural networks that defeated text CAPTCHAs -- researchers were. And they aren't solving quantum computing to undermine cryptography. The cost of spoofing an iris scan is an engineering problem. The cost of reproducing human cognition is a scientific one. These are not the same category of difficulty.
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Replies
>The first problem can be reduced to a machine learning classifier. The second is an unsolved scientific problem.
I can't believe people are still using this as a generic anti-AI argument even though a decade ago people were insisting that there's no way AI can have the capabilities that frontier LLMs have today. Moreover it's unclear whether the gap even exists. Even if we take the claim that the grid pattern is some sort of fundamental constraint that AI models can't surpass, it doesn't seem too hard to work around by infilling the grids pattern and presenting the 9 images to LLMs as one image.
How does your software work with blind people like me who use screen readers?
Your key finding is that humans process the grid as one visual scene — but that's a finding about sighted cognition.
Isn't this, like most things, a sensitivity specificity tradeoff?
How many real humans should be blocked from your system to keep the bots out?
What is the Blackstone ratio of accessibility?