A probability--time&space trade-off model in environmental risk perception

This paper addresses the issue of environmental risk perception in a multidimensional framework involving perceived risks in both time and space. A representation of the probability--time&space trade-off (PTST) is obtained in which the probability--time trade-off (PTT) and the probability--space trade-off (PST) are combined. The PST is analogous to the PTT, due to the fact that the probabilistic distance, the temporal distance, and the spatial distance are psychologically equivalent. PTST provides a formal model to accommodate the intuition of the temporal and spatial distances being a source of uncertainty in the process of environmental risk perception and provides an explicit formula to transform objective distances into a subjective probability. Finally, we present an experiment in a between-subjects design in which we manipulate the temporal and spatial distances of a water pollution risk in the questionnaires. The subjects are asked to give their probability judgments toward the spatial-temporal events and they typically believe that they are less likely to suffer health problems when the temporal and spatial distances of pollutants extend longer. The results verify the validation of the proposed PTST model.