Definition
Miller's Law (the magic number 7±2) describes the capacity of human working memory. When applied to email, it suggests that subscribers can comfortably process around 5-9 distinct pieces of information before cognitive overload sets in.
Application
- Bullet points: Limit to 5-7 key benefits or features
- Product grids: 3-4 products across (mobile-friendly) rather than 7-9
- Navigation links: 5-7 main links in header or footer sections
- Key messages: Identify your 1-3 most important points and lead with those
Why It Matters
Exceeding cognitive capacity causes subscribers to either skim past important content, miss your CTA, or close the email entirely. Structuring content within Miller's Law limits improves comprehension, recall, and action.
Related Glossary Terms
Accessible CTA (Email)
An accessible CTA is a button or link coded with sufficient colour contrast, visible focus states, descriptive screen-reader text, and a minimum touch target of 44×44 pixels.
AIDA Model for Email
The AIDA model (Attention, Interest, Desire, Action) is a classic copywriting framework used to structure email campaigns that guide subscribers from awareness to conversion.
Anchoring Effect in Email Marketing
The anchoring effect is a cognitive bias where the first piece of information presented (the anchor) influences subsequent decisions, used in email to frame pricing and value perception.
Authority Principle in Email Marketing
The authority principle is a persuasion concept where people trust and follow the guidance of perceived experts, used in email marketing through credentials, certifications, and expert positioning.
BAB Framework for Email
The BAB framework (Before-After-Bridge) is a copywriting structure that paints a picture of the subscriber's current struggle, contrasts it with a better future, and presents your solution as the bridge.
Cognitive Dissonance in Email Marketing
Cognitive dissonance is the mental discomfort experienced when holding conflicting beliefs, used in email marketing through post-purchase reassurance, objection handling, and consistency appeals.