Border bias: the belief that state borders can protect against disasters.

In this research, we documented a bias in which people underestimate the potential risk of a disaster to a target location when the disaster spreads from a different state, but not when it spreads from an equally distant location within the same state. We term this the border bias. Following research on categorization, we propose that people consider locations within a state to be part of the same superordinate category, but consider locations in two different states to be parts of different superordinate categories. The border bias occurs because people apply state-based categorization to events that are not governed by human-made boundaries. Such categorization results in state borders being considered physical barriers that can keep disasters at bay. We demonstrated the border bias for different types of disasters (earthquake, environmental risk) and tested the underlying process in three studies.