GPT-4

GPT-4 arrived in March 2023 and reset what people expected from a chatbot. It passed exams, wrote usable code, and was accurate enough that the mistakes became interesting rather than constant. Every model since has been measured against it in some way.

Two details make it a useful reference point. It stayed at the top of capability rankings for about a year, whereas leaders since then have typically held the position for around seven weeks before someone passes them. And it was trained on text alone, unlike today’s models, which also learn from images, audio and video. When people are surprised that GPT-4 could sketch a passable unicorn in code without ever having seen a picture, that is why.