The compositionality of lexical semantic representations: clues from semantic errors in object naming.

We present evidence that semantic errors in object naming can arise not only from impairment to the semantic system but also from damage to input and output processes. Although each of these levels of disruption can result in similar types of semantic errors in object naming, they have different types of consequences for performance on other lexical tasks, such as comprehension and naming to definition. We show that the analysis of the co-occurrence of semantic errors in naming with different patterns of performance in other lexical processing tasks can be used to localise the source of semantic errors in the naming process. Finally, we argue that the similarity of semantic errors in object naming, resulting from damage to different components of the naming processes by which they are activated by visual input, as well as the processes by which they activate output representations.