Reduce complexity

Complex decisions require weighing multiple factors. More information should lead to better decisions—or so the assumption goes. Yet customers ignore important details, overlook nuances, and reduce multidimensional problems to a single dimension. The question is: Why do people systematically simplify, even when complete information is available—and what does the evidence tell us?

Studies

The Dictionary Experiment

Christopher Hsee conducted a series of experiments on isolated evaluation at the University of Chicago in 1996, coining the term "Evaluability Hypothesis." He asked 150 students to evaluate two dictionaries: Dictionary A had 20,000 entries and was in mint condition, while Dictionary B had 10,000 entries but was slightly worn. In separate evaluation—where each person saw only one dictionary—participants were willing to pay an average of $24 for the mint-condition Dictionary A and only $20 for the larger but worn Dictionary B. The condition was easy to evaluate, while the number of entries was difficult to assess. In direct comparison, the relationship reversed: Dictionary B suddenly became worth $27 because the number of entries became comparable. The striking finding: the same factor (number of entries) was completely ignored when it was difficult to evaluate in isolation—even though it is objectively more important than condition.

The Apartment Experiment

Anuj Shah and Daniel Oppenheimer systematically investigated how people process multidimensional information at Princeton University in 2008. They asked 89 students to choose between two apartments. Apartment A was cheaper but had a longer commute to campus. Apartment B was more expensive but closer. The researchers varied how the information was presented: numerically ($620 vs. $730, 20 minutes vs. 10 minutes) or categorically ('cheaper' vs. 'more expensive', 'farther' vs. 'closer'). With numerical presentation, 63% of students chose based primarily on a single dimension—usually price. With categorical presentation, this proportion increased to 84%. The pattern became even more pronounced with three dimensions: 71% completely ignored at least one of the three available pieces of information. The study demonstrated that the more dimensions available, the more strongly people simplify—even when all information is presented clearly and relevantly.

Principle

Which principle for Customer Experience Design can be derived from this? The core principle is simple: reduce decisions to one clear, dominant dimension rather than presenting multiple factors as equally important. Since people naturally simplify complex decisions, companies should strategically define this dimension in advance to shape how customers evaluate their options. This approach works best for products or services with many comparable features, but is less relevant for highly emotional or very simple purchasing decisions. The key is choosing a dimension that is both meaningful to customers and favorable to your offering. The following guidelines show how to apply this principle in practice.

Guidelines

Establish a dominant dimension

Instead of presenting all product benefits as equally important, clearly define and prominently feature one primary decision dimension. For example, a financial product can be optimized for returns, security, liquidity, and costs—but the communication should lead with one factor as the main argument. Other dimensions should be communicated as satisfied requirements, not as equivalent selection criteria. This approach reduces cognitive load and prevents customers from focusing on an unintended dimension.

Making difficult-to-assess dimensions comparable

Important but abstract product features are often ignored when customers find them difficult to evaluate. The solution: Create reference points and comparisons. Instead of stating "99.8% availability," communicate "equivalent to a maximum of 17 hours of downtime per year—half the industry average." Instead of "256-bit encryption," write "the same technology banks use to protect transactions." Through contextualization, abstract features become evaluable and begin to factor into the decision-making process.

Offer pre-weighted decision matrices

When customers face complex products with multiple dimensions, they tend to simplify their decision-making by focusing on a single, often arbitrary dimension. Instead, provide structured decision aids with meaningful prioritization built in. Example: A configurator for industrial machinery shouldn't display all 15 specifications as equally important. Rather, it should group them into 'must-have criteria' (capacity, space requirements) and 'optimization criteria' (energy efficiency, maintenance intervals). This approach guides attention toward the truly decisive factors without appearing condescending.

Present information sequentially rather than in parallel

Instead of presenting all product dimensions simultaneously, guide users through the decision step by step. First, establish the primary dimension and secure commitment, then introduce additional dimensions as confirmation. For example, a software selection might begin with the core question "For how many users?"—which is easy to evaluate—followed by feature scope, integration options, and support levels, which are harder to assess. This sequencing prevents overwhelm and ensures that critical dimensions aren't overlooked.

Minimize steps

Every step is an opportunity for abandonment. The shortest path to the goal is the best. Combine what can be combined. Only ask what is truly necessary. The following examples illustrate this guideline:

• E-Commerce: Amazon's 1-Click ordering: All necessary information is already stored. One click instead of five pages – dramatically higher conversion.
• SaaS-Anmeldung: 'Sign up with Google' – one click instead of an 8-field form. Reducing it to a single step multiplies sign-ups.

Intelligent defaults for the most common cases

Set pre-selections for the most common scenarios: default the delivery address to match the billing address, pre-select the most frequently chosen shipping method, and preset typical quantities. Most users accept the defaults—not because they've carefully considered them, but because changing them requires effort. Use this behavioral tendency strategically to improve user experience and increase conversion rates.

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.