ChatGPT

ChatGPT is a chatbot developed by OpenAI and launched on November 30, 2022. Based on large language models (LLMs), it enables users to refine and steer a conversation towards a desired length, format, style, level of detail, and language. Successive user prompts and replies are considered at each conversation stage as context.[2]

ChatGPT is credited with starting the AI boom, which has led to ongoing rapid investment in and public attention to the field of artificial intelligence.[3] By January 2023, it had become what was then the fastest-growing consumer software application in history, gaining over 100 million users and contributing to the growth of OpenAI's current valuation of $80 billion.[4][5] ChatGPT's release spurred the release of competing products, including Gemini, Ernie, LLaMA, Claude, and Grok.[6] Microsoft launched Copilot, based on OpenAI's GPT-4. Some observers raised concern about the potential of ChatGPT and similar programs to displace or atrophy human intelligence, enable plagiarism, or fuel misinformation.[7][8]

ChatGPT is built on OpenAI's proprietary series of generative pre-trained transformer (GPT) models and is fine-tuned for conversational applications using a combination of supervised learning and reinforcement learning from human feedback.[7] ChatGPT was released as a freely available research preview, but due to its popularity, OpenAI now operates the service on a freemium model. Users on its free tier can access the GPT-3.5-based version, while the more advanced GPT-4 and other features are released under the "ChatGPT Plus" paid subscription service.

Training

ChatGPT is based on particular GPT foundation models, namely GPT-3.5 and GPT-4, that were fine-tuned to target conversational usage.[9] The fine-tuning process leveraged supervised learning and reinforcement learning from human feedback (RLHF).[10][11] Both approaches employed human trainers to improve model performance. In the case of supervised learning, the trainers played both sides: the user and the AI assistant. In the reinforcement learning stage, human trainers first ranked responses that the model had created in a previous conversation.[12] These rankings were used to create "reward models" that were used to fine-tune the model further by using several iterations of proximal policy optimization.[10][13]

Time magazine revealed that, to build a safety system against harmful content (e.g., sexual abuse, violence, racism, sexism), OpenAI used outsourced Kenyan workers earning less than $2 per hour to label harmful content. These labels were used to train a model to detect such content in the future. The outsourced laborers were exposed to "toxic" and traumatic content; one worker described the assignment as "torture". OpenAI's outsourcing partner was Sama, a training-data company based in San Francisco, California.[14][15]

ChatGPT initially used a Microsoft Azure supercomputing infrastructure, powered by Nvidia GPUs, that Microsoft built specifically for OpenAI and that reportedly cost "hundreds of millions of dollars". Following ChatGPT's success, Microsoft dramatically upgraded the OpenAI infrastructure in 2023.[16] Scientists at the University of California, Riverside, estimate that a series of prompts to ChatGPT needs approximately 500 milliliters (18 imp fl oz; 17 U.S. fl oz) of water for Microsoft servers cooling.[17] TrendForce market intelligence estimated that 30,000 Nvidia GPUs (each costing approximately $10,000–15,000) were used to power ChatGPT in 2023.[18][19]

OpenAI collects data from ChatGPT users to train and fine-tune the service further. Users can upvote or downvote responses they receive from ChatGPT and fill in a text field with additional feedback.