Universal Design Principles

List of 200 design principles presented in:

Lidwell, W., Holden, K., & Butler, J. (2023). Universal Principles of Design, Updated and Expanded Third Edition. Rockport Publishers.

1. Abbe Principle

Measure things so that the measuring scale is aligned with the distance being measured.

The so-called Abbe error, in physical measurements is an error that is amplified by distance. The principle can be applied to other contexts though. So are real world experiments often better than those done in the laboratory.

Therefore measurement and interventions are best taken close to the real thing.

2. Accessibility

Things should be designed to be usable, without modification, by as many people as possible.

There are four characteristics of accessible designs:

1. Perceptibility — everyone can perceive the design, regardless of sensory abilities.
2. Operability — everyone can use the design, regardless of physical abilities.
3. Simplicity — everyone can easily learn and understand the design, regardless of experience, literacy, or concentration level.
4. Forgiveness — designs minimize the occurrence and consequences of errors.

3. Ackoff’s Law

It is better to do the right things wrong than the wrong things right.

Ackoff’s law states that doing the wrong things even if perfectly executed will never be successful. While doing the right things sufficiently is more likely to succeed.

Efficiency follows strategy and agility.

Doing the right things is ‘wisdom’, and doing things right is ‘efficiency’.

4. Aesthetic-Usability Effect

Aesthetic things are subjectively perceived as easier to use than ugly ones.

Research suggest that people are more likely to accept, care for, keep, display, and repeatedly use aesthetic things. Additionally, these things are perceived to have greater value and prices than uglier things with the same functionality.

5. Affordance

The physical characteristics of a thing that influence its function and use.

If the form and features of a thing make it well suited for its intended use affordances are good. So is a button good for pushing and a lever good for pulling, but not the other way around.

Good affordances remove friction and prevent errors, while bad affordances often lead to false usage.

When affordances are correctly applied, it will seem inconceivable that a thing can function or be used otherwise.

6. Alignment

The arrangement of elements along a common axis based on their edges, centers, or areas.

7. Anchoring

The subconscious influence of reference points on decision-making and judgment.

If there is a range of different signals, the first, and last one are often taken as the anchors, with the signals in between having less of an influence.

While most of the research focusses on numbers, the effect applies to all senses. Sounds, arguments, colors all change in light of the referenced anchor.

Anchors are hard to circumvent and play a part in decision-making and judgments.

8. Anthropomorphism

The attribution of humanlike characteristics to nonhuman things.

Humans recognize certain forms and patterns as humanlike — specifically those that resemble faces and body proportions. In design this can be used to attract attention and positive feedback, if done tastefully.

Robots that interact with humans are frequently given humanlike appearances (standing upright, friendly faces) and/or communication skills. Overly realistic humanlike looks and communication are however uncanny.

Abstract anthropomorphic forms, can elicit associations of sexuality and vitality (feminine forms), empathy (babylike, round) or elicit masculine, aggressive associations (angular shapes).

9. Aposematism

The use of conspicuous markings to grab attention and signal danger.

In nature bright color combinations, behaviors such as rattling or hissing, and patterning such as zigzags and stripes attract attention and signal danger to potential predators. Aposematic signals evolved to be seen and to be remembered.

The long-wavelength colors of red, orange, and yellow are more contrasting against natural green backgrounds than green, blue, and violet and more conspicuous under a range of lighting and weather conditions. They are also effectively detected and interpreted by people with color blindness and commonly used to attract attention and signal danger in safety signage.

Aposematic patterns that feature angular versus round features appear to be the most effective danger signals to humans, such as patterns with triangles, diamonds, stripes, and zigzags.

10. Apparent Motion

The illusion of real motion created by presenting similar still images in rapid succession.

11. Appeal to Nature

The fallacy that natural things are inherently better or safer than human-created things.

12. Archetypes, Psychological

Universal forms and patterns that trigger desired emotional and attentional responses.

13. Archetypes, System

Repeating cause-effect structures that yield similar patterns of behavior across different systems.

14. Attractiveness Bias

The tendency to ascribe positive traits to attractive people and the products they use.

15. Baby-Face Bias

Tendency to perceive younger, rounder features as gentle, safe, and submissive.

16. Back of the Dresser

Apply consistent quality to all parts of a design, whether visible or hidden.

17. Biophilia Effect

Exposure to natural environments reduces stress and improves human well-being.

18. Box’s Law

All models are wrong, but some are useful; focus on the utility of simple models.

19. Brooks’ Law

Adding personnel to a late task can slow it down due to coordination overhead.

20. Brown M&M’s

Using minor indicators to verify that complex documentation has been thoroughly reviewed.

21. Bus Factor

The number of key team members who must be lost for a project to fail.

22. Cathedral Effect

Ceiling height influences thinking; high ceilings promote creativity, while low ceilings promote focus.

23. Causal Reductionism

The tendency to fixate on a single cause for complex effects while ignoring multiple causes.

24. Chesterton’s Fence

Do not change or remove something until you understand why it exists.

25. Clarke’s Laws

Maxims regarding the difficulty of distinguishing possible from impossible innovation.

26. Classical Conditioning

Influencing visceral responses by associating a neutral stimulus with a trigger stimulus.

27. Closure

The brain automatically completes recognizable forms when they are incomplete or interrupted.

28. Cognitive Dissonance

Mental discomfort caused by conflicting thoughts or values.

29. Color Effects

Instinctive or learned responses and behavioral changes triggered by exposure to colors.

30. Color Theory

Practical knowledge regarding color mixing and application to reinforce meaning.

31. Common Fate

Elements moving in the same direction and velocity are perceived as a single group.

32. Comparison

Presenting variables in common ways to illustrate patterns and relationships.

33. Confirmation

Using verification steps to minimize errors during critical or irreversible actions.

34. Confirmation Bias

The tendency to favor information that supports initial expectations while ignoring contrary evidence.

35. Consistency

Usability improves when similar things have similar styles and functions.

36. Constraint

Limiting possible actions to simplify usability and prevent errors.

37. Contour Bias

A preference for curved or contoured visual objects over angular ones.

38. Control

The level of user control should correspond to their proficiency and experience.

39. Convergence

Similar characteristics tend to evolve independently in similar environments.

40. Conway’s Law

The structure of a product reflects the communication structure of its organization.

41. Cost-Benefit

Value is determined by acquisition/use costs versus the benefits provided.

42. Creator Blindness

The inability of a creator to see fundamental flaws in their own creation.

43. Crowd Intelligence

Emergent intelligence where group averages are often better than individual responses.

44. Death Spiral

A phenomenon where groups persist in self-destructive behaviors by following flawed processes.

45. Defensible Space

Designing environments to signal ownership and deter crime through surveillance.

46. Depth of Processing

Recalling information is improved when people think hard about or analyze it.

47. Design by Committee

A consensus-based design process that often “averages out” aesthetic and functional results.

48. Desire Line

Traces of wear or use that indicate how people actually prefer to interact with a system.

49. Development Cycle

Stages of product creation: requirements, design, development, and testing.

50. Diffusion of Innovations

How new ideas and products gain acceptance across subgroups in a population over time.

51. Don’t Eat the Daisies

Exhaustive documentation cannot account for every possibility; prioritize goal clarity instead.

52. Dunbar’s Number

A theoretical limit to the number of stable social relationships one can maintain (approx. 150).

53. Dunning-Kruger Effect

Unskilled individuals overestimate their ability while experts underestimate theirs.

54. Entry Point

Initial points of entry set the emotional tone for all subsequent interactions.

55. Error, Design

Action or inaction induced by design that yields unintended or undesirable results.

56. Error, Human

Action or omission leading to an unintended result, categorized as slips, lapses, or mistakes.

57. Expectation Effects

Outcomes are changed by initial expectations (e.g., placebos).

58. Exposure Effect

Things become more likeable or credible purely through repeated exposure.

59. Face Detection

A hardwired tendency to see faces in patterns, used to grab attention.

60. Face-ism Ratio

The prominence of the face in an image influencing perceptions of character or intelligence.

61. Factor of Safety

Designing beyond expected loads to offset unknowns and prevent system failure.

62. Faith Follows Function

Prioritize functional requirements over a designer’s ideological beliefs or values.

63. Feature Creep

Continuous addition of features that increases complexity and project risk.

64. Feedback

Providing immediate information about the results of actions to aid usability.

65. Feedback Loop

A cycle where outputs are fed back into a system to stabilize or change it.

66. Fibonacci Sequence

Numerical pattern forming many organic and aesthetic structures in nature.

67. Figure-Ground

The brain automatically separates visual stimuli into focal objects and background.

68. First Principles

Irreducible truths used as the foundation for innovation and problem-solving.

69. Fitts’ Law

acquiring a target is determined by its distance and size.

70. Five Hat Racks

Organizing information in five ways: Category, Time, Location, Alphabet, or Continuum.

71. Five Tenets of Queuing

Principles for improving the psychology and experience of waiting.

72. Flexibility Trade-offs

As design flexibility increases, performance in specific tasks decreases.

73. Flow

A state of optimal experience characterized by intense focus and enjoyment.

74. Forgiveness

Designing to help users avoid errors and minimize their consequences.

75. Form Follows Function

Purpose and goal should drive the design of a product’s form.

76. Framing

Influencing decision-making by how information is presented.

77. Freeze-Flight-Fight-Forfeit

The four ways humans respond to extreme stress.

78. Gall’s Law

All successful complex systems must evolve from simple working systems.

79. Gamification

Using game mechanics to increase engagement and modify behavior.

80. Garbage In – Garbage Out

System output quality is dependent on the quality of its inputs.

81. Gates’ Rule of Automation

Automation magnifies both the efficiencies and deficiencies of a process.

82. Gloss Bias

An innate preference for glossy surfaces linked to an evolutionary need for water.

83. Golden Ratio

An aesthetic ratio of approximately 1.### 618 found in nature and design.

84. Good Continuation

Elements along smooth curves or straight lines are perceived as related.

85. Groupthink

Dysfunctional group decision-making caused by a culture of compliance and unanimity.

86. Gutenberg Diagram

The eye-movement pattern (Z-pattern) users follow on text-heavy pages.

87. Habituation

A decrease in response to a stimulus after repeated exposure.

88. Hanlon’s Razor

Malicious explanations should be avoided if incompetence or ignorance suffices.

89. Hick’s Law

Decision time increases as the number of available options increases.

90. Hierarchy of Needs

Lower-level goals (functionality) must be met before higher-level ones (creativity).

91. Highlighting

Techniques used to focus attention on specific elements or areas.

92. Horror Vacui

A tendency to fill empty space with objects or information to indicate value.

93. Icarus Matrix

Evaluating design iterations based on cost versus learning outcome.

94. Iconic Representation

Using pictorial images to make actions and concepts easier to find and learn.

95. Identifiable Victim Effect

The tendency to respond more strongly to a specific person’s plight than a large group’s.

96. IKEA Effect

Valuing things more because of the personal effort expended in creating them.

97. Inattentional Blindness

Failure to process visual inputs when attention is focused elsewhere.

98. Interference Effects

comping stimuli that slow down mental processing.

99. Inverted Pyramid

Presenting critical information first, followed by elaborative details.

100. Iron Triangle

Project constraints of time, cost, and scope.

101. Iteration

Repeating design phases (analysis, prototyping, testing) to refine versions.

102. Kano Model

Classifying features based on their impact on customer satisfaction.

103. KISS

Keep It Simple, Stupid; simple designs work better and are more reliable.

104. Knowing-Doing Gap

The disconnect between an organization’s knowledge and its actual practice.

105. Learnability

The ease with which functions can be understood and used over time.

106. Left-Digit Effect

The leftmost digit in a price disproportionately influences perceived value.

107. Legibility

The visual clarity and identification of text elements.

108. Levels of Invention

Classifying inventions from minor improvements to revolutionary breakthroughs.

109. Leverage Point

System variables where small changes produce significant effects.

110. MAFA Effect

The Most Average Facial Appearance is perceived as the most attractive.

111. Magic Triangle

Feature placement (eyes, nose, mouth) that creates the illusion of sentience.

112. Maintainability

Ease of accessing, inspecting, and repairing a system over time.

113. Mapping

The correspondence in layout/movement between controls and their effects.

114. Maslow’s Hammer

The tendency to approach all problems based only on available tools or expertise.

115. MAYA

Most Advanced Yet Acceptable; balancing novelty with familiarity.

116. Mental Model

Internal simulations of how systems or interactions work based on experience.

117. Miller’s Law

Working memory capacity is limited to roughly seven (or four) chunks.

118. Mimicry

Copying properties of familiar things to improve usability or function.

119. Minimum-Viable Product

version of a product used to gauge demand with minimum investment.

120. Mnemonic Device

Vivid imagery or rhymes used to assist in information recall.

121. Modularity

Managing complexity by dividing systems into independent units.

122. Nirvana Fallacy

Rejecting practical solutions because they are not perfect.

123. No Single Point of Failure

Designing systems to remain operational after component failure.

124. Normal Distribution

Symmetrical distribution where data clusters around a central average.

125. Not Invented Here

Tribal resistance to ideas originating outside one’s social group.

126. Nudge

Influencing behavior without restricting options or changing incentives.

127. Number-Space Associations

Serial information is intuitively organized along a spatial number line.

128. Ockham’s Razor

Selecting the simplest among functionally equivalent designs.

129. Operant Conditioning

Modifying behavior using rewards and punishments.

130. Orientation Sensitivity

Horizontal and vertical orientations are processed more easily than diagonal ones.

131. Paradox of Great Ideas

Innovative ideas appear crazy and are often opposed when first introduced.

132. Paradox of Unanimity

Total agreement in a group may signal a flawed decision process.

133. Pareto Principle

80% of system output is driven by ### 20% of its variables.

134. Peak-End Rule

Experiences are judged by their most intense point and their conclusion.

135. Performance Load

Mental or physical effort required to accomplish a goal.

136. Performance vs. Preference

Users’ preferences do not always match what helps them perform best.

137. Perspective Cues

Visual properties that create depth perception and three-dimensionality.

138. Perverse Incentive

An incentive that results in undesirable or unintended behaviors.

139. Phonetic Symbolism

The association between sounds and physical properties or meanings.

140. Picture Superiority Effect

Pictures are remembered significantly better than words.

141. Play Preferences

Biological and developmental biases in how groups engage with toys.

142. Poka-Yoke

Mistake-proofing mechanisms to detect and correct errors before failure.

143. Premature Optimization

Optimizing components before their importance is understood.

144. Priming

Activating concepts in memory to influence later behavior.

145. Process Eats Goal

Following a process even when it undermines the primary goal.

146. Product Life Cycle

Stages of product existence: introduction, growth, maturity, decline.

147. Progressive Disclosure

separation of information into layers displayed only when needed.

148. Progressive Subtraction

Systematic simplification of a design over its life cycle.

149. Propositional Density

Deep meaning conveyed relative to surface design elements.

150. Prospect-Refuge

Preference for safe spaces that allow surveillance without being seen.

151. Prototyping

creating simple models to visualize and evaluate requirements.

152. Proximity

elements close to one another are perceived as related.

153. Readability

ease with which text can be understood.

154. Reciprocity

The human tendency to respond to kind gestures with kindness.

155. Recognition over Recall

Memory for recognizing options is better than recalling them from memory.

156. Redundancy

using backup or fail-safe elements to maintain performance.

157. Reverse Salient

A lagging component that prevents total system development.

158. Root Cause

The first event in a causal chain that leads to a problem.

159. Rosetta Stone

Laying a foundation for understanding by including keys of common understanding.

160. Rule of Thirds

technique of composition where a medium is divided into thirds.

161. Saint-Venant’s Principle

Local effects of structural loads dissipate at a distance.

162. Satisficing

Selecting a satisfactory solution rather than the optimal one.

163. Savanna Preference

preference for natural environments resembling the African savanna.

164. Scaling Fallacy

Assuming forces and interactions scale linearly with size.

165. Scarcity

Desirability increases when items are in short supply.

166. Selection Bias

Distortion resulting from unrepresentative initial samples or audiences.

167. Self-Similarity

Property where repeating patterns appear at multiple scales.

168. Serial Position Effects

Better recall for items at the beginning and end of a sequence.

169. Shaping

Training behavior through successive approximations and reinforcement.

170. Signal-to-Noise Ratio

Maximizing essential information while minimizing distracting noise.

171. Similarity

Elements that look alike are automatically perceived as related.

172. Social Proof

Uncertain individuals copy the actions of others to behavior.

173. Social Trap

Individual short-term interest conflicting with group long-term interest.

174. Status Quo Bias

Tendency to favor the current state over change.

175. Stickiness

Features (SUCCESs) that make an idea memorable and shareable.

176. Storytelling

Using narrative elements to provide context and engagement.

177. Streetlight Effect

Tendency to look for information only where it is easiest to find.

178. Structural Forms

Solids, frames, and shells used as basic rigid structures.

179. Sunk Cost Effect/Fallacy

Continuing an endeavor purely because an investment was already made.

180. Supernormal Stimulus

Exaggerated stimulus version that triggers a stronger response.

181. Survivorship Bias

Focusing only on successful “survivors” and ignoring failures.

182. Swiss Cheese Model

Layered defenses used to prevent accidents.

183. Symmetry

Correspondence between configuration elements used for balance.

184. Testing Pyramid

Multilayered framework used to efficiently identify defects.

185. Threat Detection

Identifying potential danger through hardwired mechanisms.

186. Top-Down Lighting Bias

Perceiving depth based on lighting from above.

187. Uncanny Valley

Decline in likeability for objects that are almost human-like but not perfect.

188. Uncertainty Principle

Act of measuring system performance can interfere with the system.

189. Uniform Connectedness

Elements connected by visual properties like lines are perceived as related.

190. User-Centered vs. User-Driven Design

Understanding needs versus simply executing requests.

191. Veblen Effect

Products become more desirable as price increases (status symbol).

192. Visibility

Indicating system status and possible actions to aid recognition.

193. Visuospatial Resonance

Match between visible information and internal representations.

194. von Restorff Effect

Uncommon items in a group are most likely to be remembered.

195. Wabi-Sabi

Style emphasizing naturalness and subtle imperfection.

196. Waist-to-Hip Ratio

Physical ratio used as a cue for fitness and attractiveness.

197. Wayfinding

process of using environmental information to navigate to a destination.

198. Weakest Link

Intentionally weakening an element to fail safely and protect others.

199. WYSIWYG

What You See Is What You Get; design matching delivery.

200. Zeigarnik Effect

Unfinished tasks are remembered better than finished ones.