Sound-induced flash illusions at different spatial locations were affected by personality traits

Sound-induced flash illusion (SiFI) is an auditory-dominated effect in which observers will misperceive the number of flashes due to simultaneously presented beeps, which includes fission and fusion illusions. Although several individual differences have been found in SiFI, little is known about the effect of personality traits. In the present study, we presented flashes in near space and beeps in far space (Vnear_Afar) and flashes in far space and beeps in near space (Vfar_Anear) to better approximate the real world. We collected 103 participants' Big Five questionnaire results and their SiFI task performance to investigate the difference in trait level on the SiFI in the performance of accuracy, d' and c. The results show that all five personality traits had certain effects on the SiFI to different degrees, and different personality traits played different roles in the fission illusion and fusion illusion. The high agreeableness group was more prone to the fission illusion, and the report criteria were less strict. The report criteria of the low neuroticism group were stricter for the fusion illusion. The extraversion, conscientiousness and low openness groups were more prone to the fusion illusion in the Vnear_Afar condition than in the Vfar_Anear condition. The study indicated that personality traits were important but easily overlooked factors in multisensory illusion, which might make a difference between the fission illusion and the fusion illusion.