The closer they are, the more they interfere: Semantic similarity of word distractors increases competition in language production

Heterogeneous effects of semantic distance in language production have sparked a debate on the central assumption of many language production models, namely that lexical selection is a competitive process. In the present ERP study we manipulated semantic distance in the picture word interference (PWI) paradigm systematically within taxonomic hierarchies. Target - distractor pairs were either closely related members of the same basic level category, hence sharing many semantic features (e.g., orangutan and gorilla), or distantly related members of the same superordinate category, sharing fewer features (e.g., orangutan and horse). Across related conditions, broad category membership (e.g., animals) was kept constant. Naming times reflected a systematic increase of semantic interference as semantic distance decreased. Early and later ERP modulations related to the semantic distance manipulation were observed at posterior regions starting at 234 ms and with an additional fronto-central cluster starting at 346 ms. Early effects are interpreted as indexing lexical selection processes while the late effects may reflect an N400-like component. Taking the behavioral and ERP modulations together, these results are in line with models of lexical selection that include an early competitive lexical selection process.