An extension and test of converse's "black-and-white" model of response stability

In one of the most influential works in the public opinion literature, Phil ip Converse proposed a "black-and-white" model that divided respondents int o two groups: opinion holders and unstable opinion changers. We extend the model by allowing for a group that makes rational opinion changes over time . This enables us to (I) explore e hypotheses about the adequacy of Convers e's original model, (2) estimate the percentage of the population that belo ngs to each of the groups, and (3) examine the evidence for Converse's basi c claim that unstable changers truly exhibit nonattitudes. Contrary to Conv erse's suggestion that the unstable group is essentially giving random resp onses, the results imply that the response behavior of this group may be be st interpreted in terms of Zaller's notion of ambivalence. The results also undermine the measurement-error model, which maintains that unstable respo nses are mainly attributable to deficient survey instruments, not individua l opinion change. We use data collected at four time points over nearly two years, which track Swiss citizens' support for pollution reduction.