The spatial association of the mathematical symbols «minus and plus»

The influence of spatial-numerical associations in number categorization tasks has been widely discussed, while the role of mathematical symbols is less clear. Specifically, it has been demonstrated that subtraction and addition, reducing and increasing the magnitude of numbers, are associated with left and right space, respectively. This result is explained by invoking a mental number line or a semantic association. The present work investigated the role of the mathematical symbols «minus and plus» presented as fixation points in a spatial compatibility task. Results demonstrated an opposite influence of the two symbols: the processing of the «minus» facilitated responses to the target presented on the left, while the «plus» facilitated responses to the target presented on the right.