To the extent that the views of most voters on different issues do tend to be grouped into recognizable clumps, this is not because they are all going through the same coherent thought process—or any coherent thought process. It is because they are taking cues from groups with which they identify. The groups might be organized interest groups or identifiable segments of society or the economy. They might be friends and neighbors—and if so, this would accentuate the regional patterns that Pinker addressed. Most of all, the cues come from political parties. Most voters identify with Republicans or with Democrats, and because of this they tend to adopt most of the views that go with their preferred party. A person's views on some issues might underlie the party identification in the first place, but once identified, the rest of the views in the clump associated with the selected party are usually taken on as well.
Anthropologists could help in understanding this phenomenon. It is essentially a form of tribalism. People identify with either the Republican tribe or the Democratic tribe and shape their views on matters of public policy accordingly.
One indication of how much political views and alignments are at least as much a matter of group affinity as an intellectually cogent approach to formulating an ideology is the role of a very anti-intellectual factor: racial affinity and racial preference. Voters' preferences this year are at least as much divided along racial lines as in any other recent election. This no doubt reflects not only the less malign forms of racial affinity but also differential patterns of racial prejudice between followers of the two political parties.
All of this is yet another regrettable consequence of the evolution of American party politics in the direction of a sharper, harsher party division with little room for intraparty free thinking. The demise of moderate Republicans is the principal manifestation of this evolution. The message implied by much of the party politics of today is that all the right answers exist on one side of the divide or the other. This has made the American electorate more mentally lazy than ever. Its part in the political game is simply to pick a tribe and fall in line.