Pictures and Words: Priming and Category Effects in Object Processing

This study investigated the influence of semantic priming on object processing as a function of both presentation modality and object category in a reality decision task. Participants performed a mixed decision (i.e., object and lexical decisions) on picture and word stimuli presented in isolation (Experiment 1) and in a semantic priming paradigm (Experiment 2). The results showed longer RTs and more errors for picture targets than for word targets, in both experiments. Category effects were also demonstrated: biological objects were associated with longer RTs and more errors than man made objects, only for pictures in Experiment 1 but in both modalities in Experiment 2. Thus, our data reveal a word superiority effect in reality decisions, independently of semantic priming, and provide additional evidence favoring the biological/man made dichotomy. Finally, our data show that the mixed decision task only requires lexical/structural processing when stimuli are presented in isolation and may involve implicit semantic access when participants perform the task as part of a semantic paradigm.