Models of communication strictly as a function of intention and control founder when confronted by variationist findings of perseveration at different levels of linguistic structure in use. When Poplack (1981) finds that Spanish [s] leads to more [s] and that “zeros lead to zeros,” it is unclear how speaker intention is involved. But, it is clear that what a speaker says at one point will influence what this same speaker says next. Here we identify perseveration of pronominal and null subjects in three dialects of Spanish: Madrid, San Juan, and New York City. In null subject Spanish, expression of subject pronouns leads to more pronouns, and expression of null subjects leads to more nulls. We argue that a perspicuous account of perseveration may be found within Spreading-Activation Theory (Dell 1986), a psycholinguistic theory of production based on speech errors. Thus, this work integrates quantitative dialect description with psycholinguistic explanation.