The effects of inter-stimulus interval and prime modality in a semantic priming task

Abstract

Background: Semantic priming studies are employed in order to examine how various semantic contexts can influence visual word recognition processes. Although research has shown numerous factors can have an influence on the magnitude of the semantic priming effects found in lexical decision tasks, the majority of these factors have been related to the prime–target relationship itself. However, other factors have also been shown to alter the priming effect. Two such factors are the inter-stimulus interval (ISI) and presentation modality. The inter-stimulus interval may be used to independently assess automatic and strategic processes, whereas presentation modality is typically used to assess the different processing time courses that occur with spoken or written words. These factors have not been adequately investigated in the normal population. A more in-depth understanding of the relationships between prime modality, inter-stimulus interval, and word recognition processes in a sample of individuals with typical language abilities may provide valuable when examining lexical access and storage in language disordered populations such as those with aphasia. Aims: The focus of the present study was to examine the impact of relatively short and long inter-stimulus intervals on processing time in a visual and cross-modal lexical decision task. Previous research has not fully addressed whether convergent processes occur during cross-modal tasks or if an amodal semantic system exists. The utilisation of slow and fast inter-stimulus intervals should allow for a clearer distinction relative to processing. Methods & Procedures: A series of four lexical decision tasks was used to investigate reaction time and accuracy. The four tasks resulted from the combination of the independent variables ISI (0 ms or 400 ms) and prime modality (auditory or visual). Outcomes & Results: Results indicated that participants exhibited a larger priming effect when stimuli were presented in the 0 ms condition. Results also indicated that participants responded more accurately when the target word was presented auditorily. Conclusions: It was concluded that automatic spreading activation occurred in both the visual and auditory modalities, providing further evidence of an amodal semantic system. These observations are helpful in developing a clearer understanding of lexical storage and access in language impairments such as aphasia.