Cover photo by Mariia Shalabaieva on Unsplash

The buzz around GPT (Generative Pretrained Transformer) models is hard to miss and one of the most recognizable names, ChatGPT, has garnered significant attention for its AI prowess. But what exactly is ChatGPT and how does it work? This powerful conversational agent is more than meets the eye, so let's break it down really simply.

Transformers, The Heart of ChatGPT

If you were to build an elaborate Lego castle with a verbose instruction manual, you'd probably wish for a simplified step-by-step guide that could explain each piece's role and how it fits into the grand scheme of things. In Natural Language Processing (NLP), Transformers are akin to these complicated guides. They construct meaningful sentences by comprehending each word's part and how they all tie together (the context).

In the paper "Attention is All You Need" by Vaswani et al., transformers were introduced as a model architecture for NLP. They evaluate each word (or 'token') in a sentence and determine its importance in relation to other surrounding words. By paying "attention" to the context of each word, they construct a narrative, much like how we focus more on the most riveting parts of a story.

How Does ChatGPT Work?

ChatGPT could be likened to a voracious young reader, learning by poring over a vast library of text data from books, websites, and other written sources. It hasn't been explicitly instructed on the meaning of each sentence but has instead learned to predict what word logically follows a sequence of words. For instance, given the sentence "I would like a cup of...", it can surmise that a plausible completion might be "tea" or "coffee".

This approach to learning is termed unsupervised learning, where the model discerns patterns and makes predictions without being directly fed the correct answers. Through this intensive learning phase, ChatGPT gains a grasp (figuratively speaking) of grammar, worldly facts, and even some cultural norms, all from deducing what word is likely to come next!

But the learning doesn't stop there. After this unsupervised phase, ChatGPT undergoes another important step, called Reinforcement Learning from Human Feedback (RLHF). During this stage, human evaluators review and rate different model responses to a variety of example inputs. This feedback loop allows the model to fine-tune its outputs and provide even more accurate and appropriate responses.

When you engage with ChatGPT, it applies this learned knowledge to generate responses to your prompts. If you were to ask it to "Tell me a joke", it will create a sequence of words it deems to best complete this prompt, based on the patterns and information it has absorbed.

Understanding Limitations

ChatGPT's capabilities, while impressive, do come with limitations. It's vital to remember that ChatGPT doesn't "understand" text the way humans do. It doesn't possess beliefs, desires, or opinions and instead makes predictions based on patterns observed in data, not personal experiences or thoughts.

Additionally, its knowledge is bound by the timeframe of its training data. For instance, a model trained only up to 2021 will not be privy to events that occurred post-2021, in 2023.

Moreover, OpenAI has implemented stringent safety measures and guidelines for the content generated by ChatGPT. It is designed to refuse generating inappropriate or unsafe content, and efforts are constantly being made to improve its ability to detect and refuse such requests. However, it's not perfect

The Magic of ChatGPT

So there you have it! The magic of ChatGPT is less mystical and more a product of a meticulous and advanced learning process. It's a skilled Lego builder, adept at understanding each piece's role so it can construct marvelous castles without a pre-existing blueprint. It's not without its flaws but can be a powerful tool when imployed in the right context and with the right prompting!