Formulate simply

Trust is not created by content alone. The same message can appear convincing or doubtful depending on how easily it is processed. Font, contrast, and wording all influence processing fluency. The question is: Does ease of processing affect the credibility of a statement? How strong is this effect, and what evidence supports it?

Studies

The Font Contrast Experiment

Reber and Schwarz conducted a groundbreaking experiment on processing fluency in 1999. They presented 40 students at the University of Würzburg with identical statements about cities and countries—half in clear, black Arial font, the other half in pale gray, barely legible font on a white background. Participants were asked to evaluate whether the statements were true. Statements in easily readable font were rated as true 68% more often—even though the content was completely identical. Notably, the difficulty in reading was unconsciously interpreted as a signal that the information was false.

The Instruction Complexity Study

In 2008, Song and Schwarz from the University of Michigan gave twenty students fitness instructions for a stretching routine. Half received them in a clear, black Arial font, while the other half received them in a hard-to-read, ornate Brush font. Although the described exercises were completely identical, participants who received the illegible version estimated the time required at an average of 15.1 minutes, while the other group estimated only 8.2 minutes. The effort involved in reading was mistakenly interpreted as difficulty of the exercise itself. Yet everyone was aware that only the font differed.

The Stock Exchange Names Study

Alter and Oppenheimer analyzed the performance of 89 initial public offerings on the New York Stock Exchange in 2006, categorizing companies by how easily their names could be pronounced. The results were striking: stocks with easily pronounceable names like 'Barnings Inc.' rose by an average of 11% on the first trading day, while those with difficult-to-pronounce names like 'Aegeadux Corp.' gained only 3%. This effect persisted for an entire week. The phonetic simplicity of a company name alone measurably influenced how much money professional investors were willing to risk.

The Stock Name Experiment

Adam Alter and Daniel Oppenheimer investigated in 2006 whether a stock's name influences its performance. They analyzed actual initial public offerings (IPOs) of 89 companies and systematically coded how easily the ticker symbols could be pronounced. Some were simple, like KAR or TALE; others were complicated, like RDO or PXG. The astonishing result: stocks with easily pronounceable symbols rose an average of 11.2% on the first trading day, while difficult-to-pronounce ones gained only 3.4%. The effect even persisted: after six months, the difference was still measurable. Although rational stock analysis should be based on business fundamentals, the mere pronounceability of the name influenced million-dollar investments.

The Fonts Study

In 2008, Hyunjin Song and Norbert Schwarz presented twenty subjects at the University of Michigan with identical recipes—once in easy-to-read Arial and once in ornate Brush script. Participants were asked to estimate how long preparation would take. The same recipe in the hard-to-read font was estimated to take an average of 15.1 minutes, while in the readable font it was estimated at only 8.2 minutes—almost half! Even more striking: when asked whether they would try the recipe, 63% agreed when it was in Arial, but only 27% when it was in Brush. The difficulty of deciphering the text was misattributed—participants assumed it wasn't the font that was complicated, but the task itself.

The Repetition-Truth Experiment

In 1977, Lynn Hasher and colleagues at Temple University presented 60 students with a series of statements such as "The body temperature of chickens is 41°C" and "The Sahara is the largest desert in the world." Some statements were true, others false. Half of the statements were repeated in the second week. The result: Repeated statements were rated as true significantly more often—regardless of their actual truth value. False statements repeated three times showed a 23% higher acceptance rate than when first presented. The mechanism: Repetition increases cognitive ease through familiarity, and this ease is interpreted as a signal of truth.

The Readability Study of Scientific Papers

In 2013, Kimberley Isett and colleagues at Columbia University examined 742 scientific papers from physics. They analyzed linguistic complexity using sentence length, technical term density, and readability indices, then compared these measures with citation frequencies over the following five years. The surprising result: papers written in simpler language were cited an average of 2.6 times more frequently than linguistically complex papers with identical content. The researchers controlled for journal quality, author reputation, and novelty of results—the effect persisted. Simple language made research more influential.

The Stock Ticker Experiment

Daniel Oppenheimer and Adam Alter conducted a remarkable experiment at Princeton University in 2006. They analyzed 89 initial public offerings (IPOs) and examined the relationship between stock ticker pronounceability and price performance. Some tickers were easy to pronounce (KAR, BAL), while others were difficult (RDO, PXG). In the first week following the IPO, stocks with pronounceable tickers rose by an average of 11.2%, whereas those that were difficult to pronounce gained only 3.2%. The effect persisted for months: after one year, pronounceable tickers had risen 33% higher. The same researchers replicated the effect with company names: companies with simple names achieved higher valuations in the first days of trading.

Principle

Which principle for Customer Experience Design can be derived from this? Simplicity in communication builds trust because our brains unconsciously interpret easy-to-process information as a signal of truth and competence. This effect is especially powerful with complex products or services, where customers already face uncertainty—in these cases, poor readability or complicated language can further erode trust. However, the principle works best when simplified presentation doesn't appear superficial or omit important information, as this can trigger distrust. The following guidelines show how to apply this principle in practice.

Guidelines

Use readable typography

High contrast, adequate font size, proven typefaces. Every typographic obstacle reduces not only readability, but also credibility. The following examples illustrate this guideline:

• Apple: San Francisco Font, optimized for readability across all screen sizes. Clear typography as part of brand identity – and credibility.
• GOV.UK: Design system with maximum readability: 19px minimum size, high contrast, simple language. Trust through accessibility.

Writing in plain language

# Improved Text Write for a teenager: use short sentences and simple words. Use real numbers, not vague phrases. Put the most important points first—details come later. Avoid technical terms unless you can explain them in one simple sentence. The following examples illustrate this guideline:

• Hemingway App: Highlighting of complex sentences and passive constructions. The app makes visible what reduces fluency.
• Plain English Campaign: Crystal Mark for clear documents. Companies like Barclays and BT use the seal as a trust signal.

Offer curated selection

Limit choices to 3-5 carefully curated recommendations rather than displaying endless catalogs, and set the most appropriate option as the default selection. Each page should feature only one primary action—place advanced options behind a 'Show more' link. Reducing the number of decisions decreases cognitive load and increases conversion rates. The following examples illustrate this guideline:

• Netflix: 'Top 10 in Germany' – a curated list within the vast catalog. The pre-selection makes the decision easier for indecisive viewers.
• Amazon: 'Amazon's Choice' – a label that highlights one product per category. The customer no longer has to compare all 500 options.

Legible fonts across all media

Use exclusively highly legible fonts (sans-serif for screens, minimum 14px) at all customer touchpoints. Avoid playful, ornate, or overly thin fonts—especially for important information such as prices, terms and conditions, and safety notices. Research shows that hard-to-read fonts make tasks appear more complicated and reduce willingness to take action by up to 50%.

Optimize names for pronounceability

# CX Guideline: Optimize Names for Pronounceability Develop product, service, and company names that are easy to pronounce and remember. Avoid complex acronyms, unusual spellings, or special characters. Test names with non-experts: Can they pronounce the name on the first try? Stock market research demonstrates that easily pronounceable names perform better—because cognitive fluency is misinterpreted as a signal of quality.

Consistently repeat core messages

Consistently repeat your core value propositions, security guarantees, and unique selling points across all touchpoints. Use identical wording on your website, in emails, during sales conversations, and throughout support documentation. Research on the truth illusion effect demonstrates that repetition increases perceived credibility by up to 23%—familiarity creates cognitive ease, which the brain interprets as a signal of truth.

Radically reduce visual complexity

Design interfaces, forms, and documents with ample white space, clear hierarchy, and minimal visual elements. Each additional element increases cognitive load. Eliminate anything that doesn't directly support the core task. Research demonstrates that visually uncluttered designs are perceived as simpler, faster, and more trustworthy—even when the content is identical.

Technical terms only when necessary

Replace technical jargon with everyday language whenever you can do so without losing important meaning. When you must use technical terms, add a brief explanation the first time they appear. Check your writing using the Flesch Reading Ease Score – aim for at least 60 points, which is about newspaper level. Use this simple test: If a smart 14-year-old wouldn't understand it, it's too complex.

Visually resolving complexity

Transform multi-step processes into visual, step-by-step representations. Replace lengthy paragraphs with numbered steps and icons. Convert complex conditional structures into decision trees with clear yes/no branches. Follow this rule: If an explanation contains more than three nested if-then statements, create a diagram.

Progressively reveal information

# CX Guideline: Progressive Disclosure of Information Display only the essential information needed for the immediate decision. Reserve in-depth details for dedicated detail pages or place them behind a "Learn more" link. The primary level should answer: What is it? Who is it for? What does it cost? All other information belongs at the secondary level. For forms: Display only 3–5 fields at a time rather than presenting all 20 fields simultaneously.

Keep product names pronounceable

# CX Guideline: Keep Product Names Pronounceable Choose product names and designations that are pronounceable on first reading. Avoid cryptic abbreviations (like XR-7000-Pro-Plus), random number-letter combinations, and names with more than three syllables. Use this test: Can someone accurately communicate the name over the phone without spelling it out? If not, it's too complex. Simple, pronounceable names are more memorable, recommended more often, and perceived as more trustworthy.