# The AI Systems of Left 4 Dead

*Source* · `src-booth-2009-ai-systems-l4d` · status: **n/a**

| field | value |
|---|---|
| kind | Talk / video |
| authors | Michael Booth |
| venue | Artificial Intelligence and Interactive Digital Entertainment Conference (AIIDE) 2009, Stanford |
| date | 2009-10 |
| url | https://cdn.fastly.steamstatic.com/apps/valve/2009/ai_systems_of_l4d_mike_booth.pdf |
| accessed | 2026-10-24 |

## Notes

Slides hosted by Valve; venue from the AAAI AIIDE 2009 speaker list. AI Director adaptive pacing: per-survivor emotional intensity rises with damage, incapacitation, and nearby kills and decays when not engaged; phases Build Up, Sustain Peak (3-5 s), Peak Fade, Relax (30-45 s); mobs every 90-180 s on Normal; boss events (Tank, Witch, nothing) shuffled along the route.

## Backlinks (computed)

**cited by:** [Storyteller director](../mechanic/storyteller-director.md)

## Citation

Michael Booth (2009-10). *The AI Systems of Left 4 Dead*. Artificial Intelligence and Interactive Digital Entertainment Conference (AIIDE) 2009, Stanford https://cdn.fastly.steamstatic.com/apps/valve/2009/ai_systems_of_l4d_mike_booth.pdf

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Provenance: created in run `2026-10-24-taxonomy-m7`.