The claimed curvilinear link between left-right attitudes and dogmatism lacked significance tests

Evidence

Smithers and Lobley’s (1978) study comes closest of these to supporting Rokeach’s central premise of a curvilinear relationship between left-right social attitudes and D Scale scores. The subjects were 539 Bradford University (England) students. But, as Stone (1980) pointed out, no test of the significance of the curvilinear relationship was presented. — Bob Altemeyer, The Authoritarian Specter, 4254