Create clarity

Purchase decisions are postponed when uncertainty is present. Customers wait for more information before committing. Yet sometimes they would make the same decision regardless of what that additional information reveals. The question is: Does uncertainty paralyze decision-making even when it's irrelevant to the outcome, how can this blockage be overcome, and what does the evidence tell us?

Studies

The Hawaii Experiment

Amos Tversky and Eldar Shafir conducted a groundbreaking experiment in 1992 that revealed the limits of rational decision-making. They surveyed Stanford students immediately after an important final exam about an attractive special-price Hawaii vacation. Students who already knew they had passed booked at a rate of 54%—they wanted to celebrate. Those who knew they had failed booked at an even higher rate of 57%—they needed to recover. However, students who didn't yet know their exam results booked at only 32%. Keep in mind: the trip was equally attractive in all scenarios, but the uncertainty blocked decision-making entirely.

The Gambling Paradox

In the same study, Tversky and Shafir presented participants with a hypothetical gamble: a 50% chance of winning $200 and a 50% chance of losing $100. Afterward, they asked whether participants wanted a second round. Following a win, 69% said yes—they felt they were on a lucky streak. Following a loss, 59% said yes—they wanted to recoup their losses. But when the outcome of the first round remained sealed in an envelope, only 36% wanted to continue playing. The only difference: without a concrete outcome, participants lacked the emotional narrative needed to justify their decision.

Violation of rational decision-making

Shafir's experiments violated a fundamental principle of decision theory: Leonard Savage's 1954 "Sure-Thing Principle." It states that if action X is optimal in both scenario A and scenario B, then X should also be chosen when there is uncertainty between A and B. Yet people systematically made different choices under uncertainty than they did in both known scenarios. The reason: people need a concrete narrative to justify their decisions. This demonstrates that uncertainty alone can completely block rational decision-making.

Principle

Which principle for Customer Experience Design can be derived from this? The Disjunction Effect reveals that customers delay decisions when uncertainties exist—even when these uncertainties objectively shouldn't influence the decision. For customer experience, this means companies must actively eliminate all ambiguities and create a sense of completeness, rather than rationally convincing customers that open questions are irrelevant. This approach proves particularly effective in complex purchase situations or extended decision-making processes, where multiple factors can amplify uncertainty. However, the principle only works when uncertainty is genuinely resolved, not merely addressed superficially. The following guidelines demonstrate how to implement this principle in practice.

Guidelines

Offer decision checklists

Help the customer identify and resolve their own open questions. A checklist with 'Do I have all the information?' reduces the feeling of uncertainty. The following examples illustrate this guideline:

• Immobilienfinanzierung: 'Do you have all the documents? ✓ Proof of income ✓ Credit report ✓ Equity.' The checklist provides assurance that nothing is missing.
• B2B-Software: 'Clarify before purchase: Budget, stakeholders, timeline.' The explicit list helps resolve internal uncertainties.

Play through scenarios

When the customer thinks through both outcomes, the disjunction effect disappears. Interactive damage simulators, 'what-if' tools – anything that makes both scenarios concrete. The following examples illustrate this guideline:

• Versicherungen: Interactive claims simulator: 'Your bicycle is stolen. Here's how the process works...' The concretization closes the open loop.
• Altersvorsorge: 'This is what your pension looks like with/without supplementary provision.' Both scenarios visualized – the uncertainty is resolved.

Communicating product limitations

Communicate product limitations openly—transparently show who or what the product is ideal for and who or what it isn't. This honesty builds trust and prevents ill-suited purchases that lead to dissatisfaction. The following examples illustrate this guideline:

• Trade Republic: For intensive day trading with many orders per day, traditional brokers with flat-rate models are better suited.
• FINN: If you know for certain that you will use a vehicle for longer than three years, classic leasing is more economical.