Why AI chatbots make things up: hallucination explained

Why AI chatbots make things up: hallucination explained

  • December 21, 2025

If you’ve spent any time using modern AI like ChatGPT or Claude, you’ve probably had a “wait, what?” moment. You ask a question, and the chatbot gives you a perfectly formatted, highly confident answer that is completely, 100% wrong. In the industry, we call this “hallucination,” and it remains one of the most fascinating and frustrating quirks of artificial intelligence.

Even with the massive leap forward we’ve seen with “reasoner” models—which use test-time compute to “think” before they speak—AI still sometimes pulls facts out of thin air. It isn’t trying to lie to you; it’s simply doing exactly what it was designed to do: predict the next most likely word in a sequence. Understanding why this happens can help you use these tools more effectively and, more importantly, know when to take their answers with a grain of salt.

Read more