Differential effect of visual and auditory spatial cues on visual numerosity judgment
33.326, Sunday, 18-May, 8:30 am - 12:30 pm, Jacaranda Hall
Yasuhiro Takeshima1, Jiro Gyoba1; 1Tohoku University
Numerosity judgment of visual objects includes various perceptual and cognitive processes. Previous studies have indicated that there are two processes in numerosity judgmentsa subitizing process for up to three or four items and a counting process for over three or four items. These numerosity judgment processes are reported to reflect different types of attentional functions. However, the differential attentional effect between sensory modalities has not yet been well examined. The present study compared the attentional effect of auditory cues with that of visual cues on visual numerosity judgment. In Experiment 1, we directed attention by using the correspondence between visual stimulus elevation (top or bottom) and auditory pitch (high or low). In Experiment 2, we examined the effect of visual cues (upward or downward arrow) on visual numerosity judgment. The results indicated that auditory cues facilitated both the subitizing and counting processes. However, visual cues facilitated only the counting process, which is known to be related to spatial attention. Therefore, the present results replicated the facilitation effect on counting process by spatial attention. In contrast, the capacity of subitizing is reported to be related to working memory. Moreover, several previous studies found that spatial auditory cues improve the encoding process in visual working memory. These findings suggest that auditory cues could improve the capacity of the subitizing process and this possibility was confirmed by the present study. However, visual spatial attention did not affect the subitizing process. Therefore, visual and auditory spatial cues would have different facilitative functions in numerosity judgment.