  Nativism is, of course, one possibility. Natural selection might have built a specialized language faculty, containing inborn knowledge  about language (e.g., knowledge of UG), which subsequently was  selected for because it helped human children to acquire linguistic  competence, and having linguistic competence enhanced our ancestors'  fitness. A problem with this hypothesis, however, is that it is  unclear how a language faculty containing innate representations of  UG might have arisen in the human mind. One view is that the language faculty was built up piecemeal by natural selection. This approach  underlies Pinker and Bloom's (1990) and Jackendoff's (1999) proposals as to the adaptive functions of various grammatical features and  devices. Other nativists, however, reject the adaptationist  framework. For instance, Berwick 1998, has argued that efforts to  explain the piecemeal development of knowledge of linguistic  universals in our species may be unnecessary in light of the new,  Minimalist conception of syntax (see Chomsky 1995). On this view,  all parametric constraints and rules of syntax are consequences of a  fundamental syntactic process called Merge: once Merge was in place,  Berwick argues, the rest of UG automatically followed. Chomsky,  taking another tack, has suggested that language is a  ‘spandrel,’ a byproduct of other non-linguistically  directed selective processes, such as “the increase in brain  size and complexity” (1982:23). And finally Bickerton 1998, on  yet another tack, posits a massive saltative episode in which large  chunks of syntax emerged all at once, although this posit is  implicitly withdrawn in Calvin and Bickerton 2000.