Part 2: Behind the Scenes: How AI Like ChatGPT Generates Text

In our journey to understand AI hallucinations, it's crucial to first grasp how Large Language Models (LLMs) like GPT generate text. This process, rooted deeply in probabilities and patterns, is the foundation of their functionality.

Deep Dive into Text Generation Mechanics

The core mechanism behind text generation in LLMs like GPT is their ability to predict the most likely next word or phrase in a sequence. This is achieved through a complex interplay of statistical analysis and pattern recognition. Each word or phrase prediction is based on the vast amounts of text data the model was trained on, encompassing a wide range of languages, styles, and topics.

Transformer Architecture Explained

A key component in these models is the Transformer architecture. Unlike previous models that processed text sequentially, the Transformer can handle various parts of the text in parallel, greatly enhancing its efficiency. This architecture is particularly adept at understanding context within large blocks of text, a critical factor in generating coherent and relevant language.

Addressing Misconceptions about LLMs' Text Generation

Contrary to popular belief, LLMs like ChatGPT do more than just piece together parts of their training data. They are not simple copy-paste tools but sophisticated systems capable of generating new, coherent text based on learned patterns. The outputs, while influenced by the training data, are not direct replications but novel creations.

Despite these advanced capabilities, LLMs have limitations. Their lack of real-world understanding and reliance solely on text-based patterns can sometimes lead to outputs that are nonsensical or disconnected from reality—phenomena we refer to as AI hallucinations.

LLMs vs. Word Processor Autocomplete

A common question is how LLMs differ from the autocomplete feature in word processors. Unlike simple autocomplete systems, which typically predict the next few words based on recent input, LLMs like GPT can generate coherent and contextually rich text over extended narratives. This comparison illustrates the sophistication of LLMs in understanding and generating language:



Large Language Models (LLMs)

Word Processor Autocomplete

Complexity and ScaleTrained on vast, diverse datasets, allowing for a deep understanding of complex language patterns.Based on simpler algorithms with limited datasets, focusing on common word predictions.
Contextual UnderstandingCapable of grasping broader context, enabling coherent text generation over extended conversations or narratives.Limited ability to understand context, focusing on immediate preceding words.
Generative CapabilitiesCan generate entire paragraphs, simulate dialogues, answer questions, and write in various styles.Primarily designed to complete sentences or suggest the next few words.
Potential for HallucinationsCan create convincing but potentially false or nonsensical information due to their advanced generative nature.Errors are usually limited to less contextually appropriate word suggestions, not fabricated content or narratives.


While LLMs like GPT have remarkable language processing abilities, they also have inherent limitations that can lead to what we term as 'AI hallucinations.' Two key limitations are particularly instrumental in this regard:


  1. Lack of Real-World Knowledge: LLMs, including GPT, are trained on a vast array of text data, but they don't possess real-world experience or consciousness. Their 'knowledge' is limited to the patterns and information contained in their training data. This means when faced with queries requiring up-to-date information or real-world context, LLMs might generate responses that are plausible in language but disconnected from actual, current facts.
  2. No Mechanism to Validate Truth or Relevance: GPT and similar models lack an internal mechanism to judge the truthfulness or relevance of the information they generate. They can predict and form linguistically correct sentences, but they don’t have the capability to verify the factual accuracy of their own outputs. This can lead to situations where the AI confidently provides information or narratives that are coherent in structure but entirely fictional or irrelevant to the given context.


These limitations are crucial to understand as they set the stage for the occurrence of AI hallucinations – instances where the model generates text that, while statistically probable and linguistically coherent, is either factually incorrect, logically inconsistent, or contextually irrelevant.


As we've explored the intricate process of how LLMs generate text, it becomes apparent that their advanced capabilities come with unique challenges. These challenges can manifest as AI hallucinations, a subject we will delve into in the next part of our series.

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Pete Slade
November 23, 2023