Abstract: A number comparison task was performed to examine the role of attention in number processing. Two main number comparison effects, number distance effect and number notation effect, were investigated in two attention conditions: attended (fixation) or unattended (3ºleft or right beside the fixation).Different number magnitude (large: 6-9 & small: 1-4) and number notations (Chinese & Arabic) were used. The task is to compare the numbers with 5. The number distance effect and number notation effect were investigated using ANOVA analysis. Both the error rates and RT data showed that, for number distance effect, both large numbers and small numbers had very clear distance effect in attended condition; however, only small numbers had distinct distance effect in unattended condition. For number notation effect, both small numbers and large numbers had no notation effect in attended condition; however, only small numbers showed a significant notation effect (the performance of Chinese numbers were significant better than Arabic numbers) in unattended condition.

Key words: attention, number processing, number distance effect, number notation effect