03
Lesson 3 · 1 min
What a chatbot really does
A chatbot writes its answer one small piece at a time, each time picking a likely next word.
Under the hood, ChatGPT, Claude and Gemini are large language models, or LLMs. Their core skill is simple: given some text, predict what comes next.
Ask for a recipe for pho and it does not look up a recipe. It writes one, word by word, choosing words that usually follow in texts like this. Because it learned from so much text, the result is often excellent.
This explains a lot. It is why answers sound fluent and confident. It is also why they can be wrong: a sentence can sound right and still be false.
Try it below: pick the next word yourself and watch how the odds change as the sentence grows.
Guess the next word
Press Sample to let the AI add one word at a time. Then slide the temperature and try again.
The best thing about Monday is
What could come next
- the37%
- coffee22%
- that18%
- it11%
- nothing7%
- lunch5%
The AI never “knows” the next word. It gives every possible word a score, turns the scores into odds, then rolls weighted dice. Temperature changes how lopsided the dice are: at 0 it always takes the favourite, so you get the same sentence every time; turned up, long shots get a real chance and the writing gets surprising.
Do it now
Catch it predicting
- 1.Ask a chatbot to finish a famous opening line, like the prompt below.
- 2.Then ask it to finish the same line in a surprising way.
- 3.Notice that the first answer is the most common pattern, and the second is a less likely one.
Finish this sentence in three different ways, from most expected to most surprising: "Every morning before work, I..."
Words from this lesson
- LLM
- An AI trained on huge amounts of text to predict the next word, which lets it write, summarise, translate and chat.
- Chatbot
- A program you talk to in everyday language by typing or speaking, which replies in the same way.
- Model
- The trained file of learned patterns that does the actual work inside an AI product. One model can power many apps.
- Token
- A chunk of text, often part of a word, that AI reads and writes in. Limits and prices are counted in tokens.