Conversion UX psychology

Six principles from behavioral psychology that make a conversion flow feel easier and more worthwhile. Distilled from the YouTube video “The UX Psychology Behind Apps People Can’t Stop Using” (uxpeak), with implementation notes added.

Scope. Apply these only on pages and flows that sell something or require sign-up: landing pages, signup and onboarding, forms, pricing, upgrade and paywall screens, checkout. Do not apply them to informational, internal or non-conversion pages. They are conversion tactics, not general design defaults.

1. Smart defaults, not blank forms

The psychology. Every open choice costs effort, and more choices means more abandonment (the classic jam study: 24 flavors sold worse than 6). Most people (70-90%) never change a default, and read it as a recommendation.

Do.

• Pre-select the most common or most likely option (plan, currency, region, toggle).
• Pre-fill what you already know (country from locale, name from the auth provider).
• Show the payoff before the action: “12 results waiting” beats a bare “Search”.

Avoid. Defaults that quietly cost the user money or share their data. A default must be the option you would honestly recommend.