The divide between people on either side of the political aisle is now larger than at any point since 1994.

The share of Democrats expressing very unfavorable attitudes toward Republicans grew from 16 percent to 44 percent over that period, according to Pew Research Center. The percentage of Republicans holding very unfavorable views of Democrats rose from 17 percent to 45 percent.

New research in Public Opinion Quarterly identifies what could be a significant factor fueling this rise: Americans' authoritarian tendencies.

Authoritarians are predisposed toward a group-centrism that is grounded in a need for order and certainty. Partisanship, like religion, is a social identity that offers the psychological benefits of tribal membership.

The Colgate University political scientist Matthew Luttig analyzed four sets of survey data that probe respondents on these qualities. His combined results cast doubt on the conventional political science wisdom that Republicans are significantly more prone to authoritarianism than Democrats. To the contrary, he finds that authoritarians "gravitate to both parties' extremes."

In the surveys, authoritarianism is measured via a series of questions about child-rearing beliefs. In essence, they ask which one of a pair of values people see as more important for children: obedience or self-reliance; independence or respect for elders; curiosity or good manners; and being considerate or being well-behaved. Setting aside the issue of whether the questions measure learned cultural dispositions or innate temperament, they do enable researchers to assess the authoritarian values held by respondents. Intensity of partisanship, meanwhile, is measured by asking respondents whether they consider themselves to be "strong" Democrats or Republicans.

Luttig reports that in the 2012 American National Election Studies survey, 13 percent of white Democrats chose the "authoritarian" response to each of the four standard questions, while 19 percent of white Republicans did the same. On both sides, the more authoritarian picks a person made, the higher the probability that he or she would also identify as strongly partisan. (Among Democrats, strong partisanship rose from 34 to 48 percent. Among Republicans, it went from 30 to 49 percent.)

Interestingly, Luttig observes that "some of the strongest members of the Democratic Party are highly authoritarian Whites, individuals typically believed to be members of the White working class." Because many of them are also socially conservative, he speculates that this group may over time decide the GOP "provides a better 'match'" for their values.

Either way, Luttig concludes, "partisan hostility in America today is not entirely rooted in different views of the world, ideological principles, or cultural disagreements." At least part of the problem is people's "powerful but substantively vacuous authoritarian needs to belong."