Abstracts

International audienceA central question concerns how the human brain stores and accesses these conceptual representations as they related to pictures and words. The current study was aimed at investigating the object processing as a function of modality and object category, and also at evaluating semantic priming in a reality decision task. Eighty participants, ranging in age from 18 to 35 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 material consisted of 144 picture and 144 word stimuli: half of them were meaningful and the other half meaningless. The meaningful picture stimuli consisted of line drawings of easily identifiable objects. Half of the stimuli belong to biological categories, and the other half to man-made categories. The pictures were matched with respect to familiarity, visual complexity and name agreement. Half of the meaningless picture stimuli were chimeric objects and the other half, nonobjects. Chimeric objects were made up of two halves of objects, and nonobjects were constructed by mixing up the lines of several objects.French words corresponded to the objects presented as pictures. Pseudowords were constructed in accordance with the orthographic and phonological rules of French and nonwords were strings of consonants. All linguistic stimuli were matched for lengh, and legal words also for lexical frequency. Results showed longer RTs and more errors for picture stimuli than for words, in both experiments.In contrast to Experiment 1, chimeric objects were associated with shorter RTs than pseudowords, suggesting that this different pattern could be related to the prime presentation with an advantage for picture targets, since they are composed of two halves of real objects. Moreover, biological objects were associated with longer RTs and more errors than man-made for pictures for both experiments and also for words in Experiment 2. According to our data, decision task only requires lexical/structural processing when stimuli are presented in isolation whereas this task may involve implicit semantic access when it is performed as part of a semantic paradigm. A category effect was demonstrated with a word superiority in reality decision tasks, independently of semantic priming. Present findings provide additional evidence favoring the biological/man made dichotomy