Universal Principles of Design, Updated and Expanded Third Edition

127 Number-Space Associations

The intuition that serial information is spatially organized by magnitude along an axis.

People intuitively think of serial information — e.g., a string of numbers, letters of an alphabet, months of a year — in spatial terms, placed in sequential order along a “mental number line”. For example, Western-oriented cultures intuit that number sequences are spatially organized from left to right, small to large. Strong support for this association comes from the SNARC effect (spatial-numerical association of response codes), in which responses to small/large numbers are faster on the left/right side of space, respectively.1

The orientation of this mental number line depends primarily on the direction of writing and ...