Iconicity in sign language production: Task matters

The present study explored the influence of iconicity on sign lexical retrieval and whether it is modulated by the task at hand. Lexical frequency was also manipulated to have an index of lexical processing during sign production. Behavioural and electrophysiological measures (ERPs) were collected from 22 Deaf bimodal bilinguals while performing a picture naming task in Catalan Sign Language (Llengua de Signes Catalana, LSC) and a word-to-sign translation task (Spanish written-words to LSC). Iconicity effects were observed in the picture naming task, but not in the word-to-sign translation task, both behaviourally and at the ERP level. In contrast, frequency effects were observed in the two tasks, with ERP effects appearing earlier in the word-to-sign translation than in the picture naming task. These results support the idea that iconicity in sign language is not pervasive but modulated by task demands. As discussed, iconicity effects in sign language would be emphasised when naming pictures because sign lexical representations in this task are retrieved via semantic-to-phonological links. Conversely, attenuated iconicity effects when translating words might result from sign lexical representations being directly accessed from the lexical representations of the word.