I've seen a few studies about it. If i remeber correctly, basically making them talk like a caveman increases the information density of every token and decreases the chance that they would allucinate.
As sources this is the one i found but i'm sure there are others:
> Persona-based Prompting Has An Effect on Theory-of-Mind Reasoning in Large Language Models
> Text Compression as a Proxy for LLM Reasoning Efficiency
As sources this is the one i found but i'm sure there are others: > Persona-based Prompting Has An Effect on Theory-of-Mind Reasoning in Large Language Models > Text Compression as a Proxy for LLM Reasoning Efficiency