Let me begin by saying that, though I oppose ideological voter models in general, the two-dimensional model is least unrealistic. Why? Because the number of points a given distance away from a given point is proportional to the distance to the power of one less than the number of dimensions. Thus, only in two dimensions is the number of points a given distance away from a given point proportional to the distance. That’s consistent with kinship, in which the average individual’s number of relatives of a given coefficient of relationship is proportional to the reciprocal of the coefficient of relationship.
But the problem with ideological voter models is that they allow voters to inhabit an objective center, whereas in reality we’re all extremists, each the center of his own universe, with concern for others that diminishes as rapidly as kinship. Our parents are marginally more centrist, having twice our kinship with everyone but ourselves, but only Adam and Eve are truly centrist.
What I propose is a family tree voter model, in which a candidate’s utility is equal to the product of his fitness and his coefficient of relationship to the voter. It is unnecessary that a candidate actually have his coefficient of relationship, only that he acts as if he does (though it’s worth noting that we evidently prefer elderly candidates, verging on senility, which is hard to explain without a literal family tree model).