Serial Position Effects and Lexical Activation in Spelling: Evidence from a Single Case Study

Abstract

A single case study of a 'deep dysgraphic' patient is reported. The majority of her errors consist of non-word and fragment responses in which initial letters tend to be correctly produced (e.g. book ? b, dentist ? dentant). The probability of making an error at a given position increases linearly from word beginning to word end for all spelling tasks requiring lexical access. This serial position effect cannot be attributed to damage to the graphemic buffer, since a different pattern is found in a buffer-taxing task which does not require lexical access. It is also unlikely to reflect a neglect deficit, since the serial position effect is related to ordinal positions rather than positions left or right of word-centre. It is argued that the patient's pattern reflects incomplete activation of lexical-orthographic representations. Our data are consistent with models of lexical activation in which the activation of letter nodes is a function of ordinal position.