Enriqueta Aragones

The Effect of Candidate Quality on Electoral Equilibrium: An Experimental Study

When two candidates of different quality compete in a one-dimensional policy space, the equilibrium outcomes are asymmetric and do not correspond to the median. There are three main effects. First, the better candidate adopts more centrist policies than the worse candidate. Second, the equilibrium is statistical, in the sense that it predicts a probability distribution of outcomes rather than a single degenerate outcome. Third, the equilibrium varies systematically with the level of uncertainty about the location of the median voter. We test these three predictions using laboratory experiments and find strong support for all three. We also observe some biases and show that they can be explained by quantal response equilibrium.

Candidate quality in a downsian model with a continuous policy space

This paper characterizes a unique mixed strategy Nash equilibrium in a one-dimensional Downsian model of two-candidate elections with a continuous policy space, where candidates are office motivated and one candidate enjoys a non-policy advantage over the other candidate. We show that if votersʼ utility functions are concave and the median voter ideal point is drawn from a unimodal distribution, there is a mixed strategy Nash equilibrium where the advantaged candidate chooses the ideal point of the expected median voter with probability one and the disadvantaged candidate uses a mixed strategy that is symmetric around it. Existence conditions require the variance of the distribution to be small enough relative to the size of the advantage.

Campaign Rhetoric: A Model of Reputation

We analyze conditions under which a candidates campaign rhetoric may affect the beliefs of the voters over what policy the candidate will implement in case he wins the election. We develop a model of repeated elections with complete information in which candidates are purely ideological. Voters strategies involve a credible threat to punish candidates that renege of their campaign promises, and in equilibrium all campaign promises are believed by voters, and honored by candidates. We obtain that the degree to which promises are credible in equilibrium is an increasing function of the value of a candidates reputation.

Government formation in a two dimensional policy space

Given any allocation of parliament seats among parties, we characterize all the stable government configurations (supported by at least a majority of the parliament) in terms of winning coalitions and policy outcomes. We consider a two dimensional policy space and we assume that there are four parties that care mainly about holding office, and only instrumentally about policy. We find that for any distribution of seats in the parliament only two scenarios are possible: either there is a party that is a member of almost all equilibrium coalitions (dominant party scenario) or there is a party that is never a member of an equilibrium coalition (dominated party scenario). We characterize the key party for each possible scenario and we show that it is sufficient that the key party has intense preferences over one the issues to guarantee the formation of a stable government coalition.

Accuracy Vs. Simplicity: A Complex Trade-Off

Inductive learning aims at finding general rules that hold true in a database. Targeted learning seeks rules for the predictions of the value of a variable based on the values of others, as in the case of linear or non-parametric regression analysis. Non-targeted learning finds regularities without a specific prediction goal. We model the product of non-targeted learning as rules that state that a certain phenomenon never happens, or that certain conditions necessitate another. For all types of rules, there is a trade-off between the rules accuracy and its simplicity. Thus rule selection can be viewed as a choice problem, among pairs of degree of accuracy and degree of complexity. However, one cannot in general tell what is the feasible set in the accuracy-complexity space. Formally, we show that finding out whether a point belongs to this set is computationally hard. In particular, in the context of linear regression, finding a small set of variables that obtain a certain value of R2 is computationally hard. Computational complexity may explain why a person is not always aware of rules that, if asked, she would find valid. This, in turn, may explain why one can change other peoples minds (opinions, beliefs) without providing new information.

Incumbency (Dis)Advantage When Citizens Can Propose

This paper analyses the problem that an incumbent faces during the legislature when deciding how to react to citizen proposals such as the outcome of referenda or popular initiatives. We argue that these proposals constitute a potential source of electoral disadvantage when citizens factor in their evaluation of the incumbent his reaction to these proposals. This is because an incumbent politician may jeopardize his re-election by implementing policies close to his preferred ones but unpopular among the electorate. We characterize conditions under which this potential disadvantage becomes in fact an electoral advantage for the incumbent. We fi nd that the choices of the incumbent during the legislature will be closest to citizens policy proposals when the intensity of electoral competition is neither too soft nor too tough. Finally, we use our results to discuss some implications of the use of mechanisms such as referenda and popular assemblies on electoral competition and on the incumbency advantage phenomenon.

Fact-Free Learning, Second Version

People may be surprised by noticing certain regularities that hold in existing knowledge they have had for some time. That is, they may learn without getting new factual information. We argue that this can be partly explained by computational complexity. We show that, given a knowledge base, finding a small set of variables that obtain a certain value of R2 is computationally hard, in the sense that this term is used in computer science. We discuss some of the implications of this result and of fact-free learning in general.