Zero-risk bias

Biological Parallel

Territorial animals preferentially eliminate minor threats completely (zero snakes in core territory) over reducing major threats partially (80% fewer lions overall). Zero creates categorical certainty: this zone is SAFE. Partial reduction leaves residual uncertainty requiring ongoing vigilance—you must still monitor for the 20% lion encounters. The bias reflects binary ancestral categories (safe vs unsafe, edible vs toxic) where complete elimination offered cognitive closure and freed attention. Zero percent means you can stop monitoring entirely.