Perceptual priming is not a necessary consequence of semantic classification of pictures

Four experiments investigated how repetition priming of object recognition is affected by the task performed in the prime and test phases. In Experime nt 1 object recognition was tested using both vocal naming and two differen t semantic decision tasks (whether or not objects were manufactured, and wh ether or not they would be found inside the house). Some aspects of the dat a were inconsistent with contemporary models of object recognition. Specifi cally, object priming was eliminated with some combinations of prime and te st tasks, and there was no evidence of perceptual (as opposed to conceptual or response) priming in either semantic classification task, even though p erceptual identification of the objects is required for at least one of the se tasks. Experiment 2 showed that even when perceptual demands were increa sed by brief presentation, the inside task showed no perceptual priming. Ex periment 3 showed that the inside task did not appear to be based on concep tual priming either, as it was not primed significantly when the prime deci sions were made to object labels. Experiment 4 showed that visual sensitivi ty could be restored to the inside task following practice on the task, sup porting the suggestion that a critical factor is whether the semantic categ ory is preformed or must be computed. The results show that the visual repr esentational processes revealed by object priming depend crucially on the t ask chosen.