13.5 Direct attention

Use position, contrast, size, and annotation to guide attention. When most values provide context and one requires action, a restrained highlight is often more effective than a rainbow palette.

Visual grouping follows familiar principles:

• proximity suggests relatedness;
• similarity suggests membership;
• enclosure creates a group;
• connection implies a relationship; and
• continuity helps the eye follow a pattern.

Use these effects deliberately. A shared colour may imply that two categories are related even when they are not.