The Influence Of Auditory Spatial Attention On Cross-modal Semantic Priming Effect

Target stimulus is recognized faster and more accurately when a semantically related prime stimulus is presented before, which is named the semantic priming effect. Some researchers have explored the semantic priming effect under different stimulus contents or modalities, and under the effect of attention or consciousness. They found that semantic priming could trigger the N400 effect. However, there are few studies on the influence of attention on cross-modal semantic priming effect. In order to explore the relationship between them, we used Event-Related Potentials(ERP) to study the further efforts among the N400 effect by analyzing the cross-modal semantic priming effect under the influence of auditory spatial attention using a combined auditory spatial attention and cross-modal priming paradigm.This experiment used the common animals-describing pictures and artificial objects in daily life as the visual priming stimuli and corresponding sounds as the auditory target stimuli. In order to obtain the direction information, the sounds were filtered by the head-related transfer function(in a horizontal plane, 45° to the ahead direction on the left and right). Before each stimulus was presented, the monitor instructed the attended direction to the subjects, then the subjects were asked to concentrate on the sound from the attended direction and tried to ignore the sound from unattended direction, at last a classification judgment from the attended direction was presented.The behavioral result indicated that the subjects had a higher correct rate among the classification judgment when attended sounds were semantically congruent with prime pictures than when attended sounds were semantically incongruent with prime pictures. Meanwhile, the ERP result found that the incongruent sounds triggered a negative-going deflection than the congruent sounds, which is called N400 effect. This phenomenon was mostly observed in the frontal, fronto-central, central, centro-parietal and parietal areas on the brain, which was consistent with the previous studies of the cross-modal semantic prime, suggesting that the N400 effect reflected the contextual integration process of the visual-auditory information. Moreover, our result also found that not only the attended sounds but also the unattended sound could induce the N400 effect, suggesting that N400 effect could be observed even if the sound was beyond the focus of attention. Further analysis found that the N400 effect triggered by the attended sound was stronger than that by the unattended sound, suggesting that cross-modal semantic priming effect might be modulated by attention processes.In conclusion, through the further analysis of the relationship between attention and the cross-modal semantic priming effect, we shed new light on the semantic priming effect, and provided more scientific basis for the understanding of the cognition mechanism on semantic priming effect.