Thierry Grenot
Thierry Grenot

Hallucinations, LLMs and conversational AI

Hallucinations, LLMs and conversational AI

What is a hallucination?

Hallucinations are “false or misleading responses that appear plausible”, presented with confidence. Concrete examples: fabricated statistics, invented quotations, fictional historical events, names of places or people created from thin air.

Understanding large language models

LLMs are deep neural networks trained on massive datasets to predict the next word. Their key characteristics:

  • Excellence in generating syntactically correct text
  • Absence of genuine understanding or semantic knowledge
  • Computation-based rather than comprehension-based function
  • Training requiring billions of parameters and thousands of specialised servers

The origins of LLM “knowledge”

Knowledge emerges from training data rather than inherent understanding. For ChatGPT and similar models, web content provides contextual information. LLMs calculate “most probable word sequences” rather than determining factual accuracy.

Why LLMs seem magical

Their appeal stems from natural language interaction — a conversational rather than formal mode. Users perceive them as understanding because they respond contextually and maintain dialogue coherence.

Causes of hallucinations

  • LLMs’ inability to distinguish probable sequences from accurate ones
  • Insufficient, biased or misleading training data
  • Ambiguous or imprecise prompts

Research suggests hallucinations are inherent to LLM technology: “Hallucination is Inevitable: An Innate Limitation of Large Language Models”.

Professional consequences

In a business context, hallucinations risk:

  1. Spreading misinformation — particularly dangerous in journalism, science and medicine
  2. Creating legal liability — incorrect financial or legal advice causing damages
  3. Eroding trust — clients losing confidence in organisations using unreliable AI
  4. Causing strategic errors — false data influencing business decisions
  5. Causing ethical harm — especially in healthcare and public policy

LLM hallucinations in a professional context

Mitigation strategies

Current approaches include:

  • Adding semantic capabilities through intent recognition
  • Contextual coherence analysis
  • Mixture of Experts (MoE) architecture
  • Comparing outputs across multiple LLMs
  • Human annotation for model refinement
  • Retrieval-Augmented Generation (RAG) systems

Key takeaway

LLMs revolutionise conversational AI through fluent text generation, but require robust verification mechanisms and user education — particularly in precision-critical sectors such as law, finance and healthcare.