 From the 1960's onwards the party systems discussed in Lipset and Rokkan's theory partially 'unfroze' as the traditional cleavages seemed to become less deterministic for voting behaviors than before.The importance of the religious cleavage, for example, has significantly declined because of widespread secularization.Some authors argue that from this period onwards cleavages have therefore lost their overall importance for political outcomes, as particularization and individualization of voters supposedly caused the decline in overall political party identification and group formation.