Universal Principles of Design, Updated and Expanded Third Edition

130 Orientation Sensitivity

Certain line orientations are more quickly and easily processed and discriminated than others.

The efficiency with which people can perceive and make judgments about the orientation of lines is influenced by a number of factors. For example, the time displayed on a standard analog clock can be quickly interpreted because the numbers are positioned at 30-degree increments around the center. The 30-degree increment happens to correspond to the minimum recommended difference in line orientation required to be easily detectable—i.e., differences in line orientation of less than 30 degrees require more effort to detect.¹

Orientation sensitivity is based on two phenomena:

1. Oblique effect—The ability to more accurately perceive ...