AI hallucinations sound bad, but what are they?

When I asked Gemini the following question: “What are ai hallucinations?” Here is the respose: AI hallucinations refer to instances where the AI generates outputs that are:

• False or misleading: The AI presents information as factual, even though it’s incorrect or fabricated.
• Nonsensical or illogical: The output might be incoherent or lack a clear connection to reality.
• Fabricated: The AI might invent information, such as nonexistent facts, sources, or events.

When I asked Gemini what the causes of these hallucinations are, I got the following response: “Training data issues: Biased, incomplete, or flawed training data can lead AI models to learn incorrect patterns. Lack of grounding: AI models may struggle to connect their knowledge to real-world facts and contexts. Overfitting: When a model memorizes training data too closely, it can perform poorly on new, unseen data, leading to fabricated outputs.