Less at once

Purchase decisions require processing—comparing options, weighing information, and retaining details. But human capacity is limited. The question is: How much information can a person process simultaneously, and what happens when this limit is exceeded? What evidence exists about this phenomenon?

Studies

The Magic Number Seven

In 1956, George Miller conducted psychology's most famous memory experiment at Harvard University. He had hundreds of test subjects listen to number sequences like "3-8-1-9-4-2-7" and immediately repeat them. Whether numbers, letters, or tones, around 7 elements was the limit. Then Miller discovered something fascinating: participants who stored "1-9-8-4" as a year rather than four individual digits could suddenly remember much longer sequences. The surprising finding: it's not the amount of information that's limited, but the number of memory slots—and we determine what fits into a slot through clever "chunking."

Why Chess Masters See More

William Chase and Herbert Simon tested chess players of varying skill levels at Carnegie Mellon University in 1973. They showed participants a position with 25 pieces for just 5 seconds. Masters subsequently reconstructed 16-20 pieces correctly, while beginners recalled only 6-7. The crucial test came when they used randomly placed pieces that never occur in real games—the advantage disappeared completely, with both groups recalling only about 6 pieces. The key insight: masters don't store individual pieces but rather familiar attack patterns as chunks. Without meaningful structure, even decades of expertise cannot overcome the 7±2 rule.

Principle

Which principle for Customer Experience Design can be derived from this? Structured summaries at the end of customer conversations or complex interactions are essential for transferring critical information from limited working memory into permanent long-term memory. Since people can only process approximately 4-7 units of information simultaneously, important details and agreements are easily lost without systematic consolidation. Summaries are particularly effective when they not only recap the discussed points but also define clear next steps and responsibilities—this creates both clarity and commitment. However, this principle only works if the summary itself avoids overload and focuses on the truly essential points. The following guidelines demonstrate how to implement this principle in practice.

Guidelines

Summarize conversations in writing

Send a written summary via email after each consultation—including the options discussed, decisions made, and next steps. Working memory loses details quickly. A written summary prevents "I thought you said..." misunderstandings and provides the customer with a document to reference and share. The following examples illustrate this guideline:

• Finanzberatung: After each conversation: 'Summary of your appointment on [Date]: We discussed... You decided... Next steps are...'
• Möbelhaus-Beratung: After kitchen planning: PDF with all dimensions, selected appliances, materials, and the agreed delivery date.

Document next steps

At the end of every customer conversation, document who will do what and by when. Unclear next steps lead to stagnation. The customer waits, the company waits, and nothing happens. A clear action list—"You'll send us the measurements by Friday. We'll prepare the quote by Wednesday"—creates accountability and prevents momentum loss. The following examples illustrate this guideline:

• Projektmanagement-Prinzip: Like 'action items' in meetings: task, person responsible, deadline - for every customer contact.
• CRM-Integration: Automatic reminders to both parties when deadlines are approaching or have been exceeded.

Assign responsibilities clearly

Assign a personal contact person by name with direct contact information. Anonymous ticket systems and rotating contact persons create frustration. A named representative ('Your contact person is Maria Müller') gives customers security and increases their perception of the company's commitment. The following examples illustrate this guideline:

• Premium-Service: 'Your personal advisor' instead of 'The support team will take care of it'. Photos and direct phone extensions strengthen the connection.
• Handwerker-Portale: MyHammer demonstrates: Customers want to know who's coming - name, photo, reviews. The same applies to service contacts.