Adaptive Decision-Making and the Vote: The Case of Spain

Abstract

The normative focus of the study of political behaviour assumes that voters are rational and that all apply the same method of reasoning when they have to choose. Given the limitations of the normative view of voting theory, some authors have chosen to explain the voter’s decision from a descriptive perspective. In this paper, we develop an adaptive model to describe the different decision-making processes that voters apply. Our ultimate goal is to identify rules that characterize the political behaviour of individuals. To achieve this, we use a classification technique from the field of automatic learning: decision trees. At the empirical level, we have discovered that Spanish voters apply different decision processes that are guided by the heuristic criterion of cost saving of information about the incumbent, the government’s actions and the future of the country’s economy. The decision trees obtained enable us to classify voters into four categories: ritualists, voters influenced by affective factors, those influenced by government performance and forward-looking voters.