185+ Principles to Validate Any Design

Working memory holds only 7±2 items. Cutting cognitive load lifts productivity up to 500% and reduces errors through simpler interfaces.

Nielsen's consistency heuristic (1990) demonstrates internal and external consistency reduce cognitive load 30-40%, with users operating 40-50% faster (Shneiderman 1987) through predictable patterns enabling automatic responses versus conscious interface relearning for designers.

Nielsen's Jakob's Law (2000) demonstrates users spend 95-99% time elsewhere creating dominant mental models, with Carroll (1987) showing familiar patterns execute 5-10× faster through positive transfer for designers.

Hick's Law (1952) demonstrates decision time increases logarithmically T = a + b log₂(n) with choice alternatives, showing 2 choices require 380ms, 4 choices 520ms, 8 choices 680ms, with each doubling adding constant 150-200ms increment through hierarchical brain processing.

Reveal complexity in stages so users aren't overwhelmed. Progressive disclosure cuts time to first action 30-50% while keeping 70-90% feature discovery.

Fitts's Law (Fitts 1954, MacKenzie 1992) demonstrates movement time follows MT = a + b × log₂(2D/W), with larger closer targets reducing interaction time 40-60% and error rates 50-70% through quantifiable motor performance optimization.

Poor conversational design increases clarification requests 3-5x. Apply Grice's maxims to build chatbots and voice UIs that users actually understand.

AI transparency (DARPA XAI 2017, Jobin et al. 2019) requires explainable reasoning and disclosed limitations, with transparent systems improving decision accuracy 40-60% and reducing bias 30-40% through verified reasoning and appropriate trust calibration.

Inclusive wellbeing (Holmes 2018, WHO 2020) optimizes for physical, mental, emotional, and social health across diverse populations, proactively designing for stress reduction, social connection, and meaningful engagement beyond task completion.

Chunking organizes information into meaningful groups enabling users to remember 40 binary digits (Miller 1956) versus 7-9 individually, multiplying effective working memory capacity by restructuring content to align with 7±2 cognitive constraints rather than attempting to expand fundamental limits.

Miller's Law: humans hold 7 chunks in working memory. Keep menus, forms, and options within this limit to cut cognitive load and boost task completion.

Recognition beats recall consistently with 85-95% accuracy versus 35-50% (Tulving 1973), requiring substantially less mental effort as interfaces providing visible cues outperform memory-dependent navigation by making options visible rather than requiring users to remember information.