MIT and Harvard build MatrAIx, an AI simulation of 8.3 billion virtual humans
alex_verem · x · 2026-11-11
- MIT and Harvard researchers built MatrAIx, an AI simulation of 8.3 billion virtual people—roughly Earth's entire population.
- Each persona carries up to 1,290 traits (age, language, job, personality, habits, risk tolerance) and acts like a real user: filling surveys, talking to chatbots, shopping, clicking through real desktop and mobile apps.
- The team ran 18,189 tests across 8 tasks using Anthropic and OpenAI models; personas stayed true to assigned traits in 91.5% of controlled trials, dropping to 83% inside real apps.
- 1 million personas are released free for non-commercial research; 600k were built from public data (Wikipedia bios, Amazon reviews, surveys) with names and contact details removed.
- The authors stress human studies are still needed before applying results to real people or big decisions—but simulations can flag bad prices or confusing screens before launch.
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