This paper identifies a feature of human brain neural nets that may be described as the principle of ease of processing (PEP), and that, it is argued, is the primary force guiding a learner towards a target grammar. It is suggested that the same principle lies at the heart of Optimality Theory, which characterizes the course of language acquisition as a progressive reranking of a hierarchy of universal and violable constraints. It is observed that the hierarchy a learner is in possession of at any particular time is the learner's present characterization of the grammar of the target language and will determine what outputs nets involved in linguistic processing produce for any given inputs to those nets. It is suggested that spatial metaphors may give a clearer insight into the workings of neural nets, and that the process of self-organization of nets is seen in accordance with the PEP as a realignment of the positions of linguistic elements in a multidimensional space that is a characterization of the target language. (Contains 46 references.) (Author/NAV)