Why do people misperceive long-term environmental change?

Environmental sciences seek to provide an unbiased quantitative and mechanistic basis for decision making, but conservation and management are often driven by personal perception of the environment. This, in turn, is made up of personal experiences, information exposure, personal values and beliefs. When documented changes in the natural world are in dissonance with people’s perceptions, unintended environmental consequences (e.g. overlooked degradation, unacknowledged conservation successes) may occur. Here we compare long-term changes in the abundance of trees and birds and human perception thereof. We identify mismatches and personal characteristics driving these mismatches. We find that people were more often wrong than right (66% of the cases) in their assessment of species’ changes that occurred in their lifetime, and change blindness prevailed as a perception phenomenon. Importantly, when species populations increased, respondents often exhibited change blindness, while population declines were more accurately perceived. This finding underlines the importance of relying on hard data rather than perception for decision making. Our study has implications for conservation science, restoration and land management practice, for which we recommend that (long-term) decision making should integrate hard monitoring data to mitigate the effects of change blindness and shifted baselines.