ChatGPT: what can the extraordinary artificial intelligence chatbot do?

The program is the latest to emerge from OpenAI, a research laboratory in California, and is based on an earlier AI from the outfit, called GPT-3. Known in the field as a large language model or LLM, the AI is fed hundreds of billions of words in the form of books, conversations and web articles, from which it builds a model, based on statistical probability, of the words and sentences that tend to follow whatever text came before. It is a bit like predictive text on a mobile phone, but scaled up massively, allowing it to produce entire responses instead of single words.

The significant step forward with ChatGPT lies in the extra training it received. The initial language model was fine-tuned by feeding it a vast number of questions and answers provided by human AI trainers. These were then incorporated into its dataset. Next, the program was asked to produce several different responses to a wide variety questions, which human experts then ranked from best to worst. This human-guided fine-tuning means ChatGPT is often highly impressive at working out what information a question is really after, gathering the right information, and framing a response in a natural manner.