Artificial intelligence, explained
What AI and large language models are, who builds them, and why it matters.
Artificial intelligence (AI) is software that performs tasks we usually associate with human intelligence — recognising images, understanding language, writing text or making predictions. Most of today's excitement is about a branch called machine learning, where systems learn patterns from vast amounts of data rather than being programmed with fixed rules.
Large language models
The tools behind chatbots like ChatGPT, Claude and Gemini are 'large language models' (LLMs). They are trained on enormous quantities of text and learn to predict the next word, which lets them answer questions, summarise and write. They are powerful but imperfect — they can sound confident while being wrong, an error often called a 'hallucination'.
Who builds it, and what it needs
A handful of well-funded labs — including OpenAI, Anthropic and Google DeepMind — lead the field, alongside big technology companies. Training these models requires huge amounts of computing power, which is why specialised chips (from firms such as Nvidia) and vast data centres have become so valuable.
Promise and worry
AI is being used in medicine, science, software and everyday tools. It also raises real concerns: misinformation, job disruption, bias, and questions about safety and control — which is why governments are now writing rules for it. See our glossary for the key terms.