Perplexity measures how predictable words are in a text. Lower perplexity means logical and fluent writing. Higher perplexity indicates unusual word choices or confusing structures. AI content often scores low in perplexity, while human writing shows more variety.

Burstiness looks at sentence variation. Human writing tends to have higher burstiness, mixing short and complex sentences for rhythm. AI, however, produces flatter, repetitive text with low burstiness.

Examples

• High perplexity: incoherent sentences with unexpected word order.
  
  

• Low perplexity: common phrases with logical flow.
  
  

• High burstiness: diverse sentence lengths and dynamic flow.
  
  

• Low burstiness: repetitive patterns and uniform structure.
  
  

Role in AI Detection
AI detectors use burstiness and perplexity to distinguish human text from machine-generated content. Humans naturally introduce unpredictability and variety, while AI sticks to safer, predictable patterns.

By mastering burstiness and perplexity, writers can create engaging content, and researchers can train AI to sound more human.

View details here: What is Perplexity And Burstiness in AI Writing?