Politicians, the Representativeness Heuristic and Decision-Making Biases

Do politicians use the representativeness heuristic when making judgements, that is, when they appraise the likelihood or frequency of an outcome that is unknown or unknowable? Heuristics are cognitive shortcuts that facilitate judgements and decision making. Oftentimes, heuristics are useful, but they may also lead to systematic biases that can be detrimental for decision making in a representative democracy. Thus far, we lack experimental evidence on whether politicians use the representativeness heuristic. To contribute to and extend the existing literature, we develop and conduct a survey experiment with as main participants Dutch elected local politicians from the larger municipalities (n = 211). This survey experiment examines whether politician participants display two decision-making biases related to the representativeness heuristic: the conjunction error and scope neglect. We also run the experiment with a student sample (n = 260), mainly to validate the experimental design. Our findings show that politician participants neglect scope in one scenario and that they display the conjunction error in two of three scenarios. These results suggest that politician participants use the representativeness heuristic. Conversely, our third conjunction error scenario does not find evidence for politician participants displaying this bias. As we discuss in the article, the latter may be an artifact of our experimental design. Overall, our findings contribute fundamentally to our understanding of how politicians process information and how this influences their judgements and decision making