August 31, 2025

How was ChatGPT Created?

ChatGPT was created by OpenAI using a machine learning technique called deep learning, specifically a type of model known as a transformer neural network. Here’s a simplified breakdown of how it was built:

1. Base Technology: The Transformer

  • Introduced in a 2017 paper called “Attention Is All You Need”, transformers are designed to understand and generate human-like language.
  • They process words in relation to all other words in a sentence (via “attention”), which makes them much better at understanding context.

2. Pretraining (Learning Language)

  • The model was trained on a large corpus of text from the internet (books, websites, articles, etc.).
  • It used a technique called unsupervised learning, where it learned to predict the next word in a sentence. For example:
    • Input: “The cat sat on the”
    • Target: “mat”
  • This phase is called pretraining, and it helps the model learn grammar, facts, reasoning, and basic world knowledge.

3. Fine-Tuning with Human Feedback

  • After pretraining, the model was fine-tuned using Reinforcement Learning from Human Feedback (RLHF):
    • Human reviewers ranked model outputs based on quality.
    • These rankings were used to train a reward model.
    • The model was then optimized to generate responses that humans rate more highly.
  • This is what makes ChatGPT more helpful, honest, and aligned with user intentions.

4. Continuous Updates

  • OpenAI continues to improve the model with new training methods, safety features, and user feedback.
  • ChatGPT now runs on GPT-4 (as of 2024), which is more powerful and refined than earlier versions.