Prototype Effect

Products are explained through examples—cars through reference models, software through use cases, insurance through sample customers. The intuitive assumption: concrete examples make abstract concepts tangible and understandable. Yet every example carries the risk of narrowing rather than broadening perception. Customers might think, "That's not me" or "I don't need that." The question is: when do concrete examples aid understanding, and when do they limit it—and what does the evidence tell us?

Studies

The Art Pictures Experiment

Douglas Medin and Marguerite Schaffer conducted an experiment on category formation at the University of Illinois in 1978. Sixty-four students learned to assign abstract geometric patterns to two fictitious artists. Each 'artist' had a prototype with five characteristic features—such as specific shapes, colors, and arrangements. However, participants never saw the prototypes themselves, only variations containing 3-4 of the typical features. In the test phase, they were asked to categorize new patterns. The surprising result: categorization did not follow the abstract prototype but rather the similarity to the concrete training examples they had seen. Patterns that resembled many training examples were categorized faster and more confidently—even when they were further from the theoretical prototype. The observed exemplars, not the abstract rule, determined the category boundaries.

The Law Students Study

In 1977, Lee Ross and colleagues at Stanford University investigated how law students work with legal precedents. They presented 90 students with two court cases involving a fictitious legal problem. Half the students received two very similar cases, while the other half received two different cases. The students were then asked to evaluate a new case. Those who had studied similar example cases applied the underlying principles much more narrowly—only when the new case strongly resembled their examples. In contrast, the group exposed to different examples recognized the broader principle and applied it more flexibly. A single example, or very similar examples, narrowed students' conception of when a legal principle applies. Only exposure to a range of different examples enabled transfer to new situations. The concrete examples shaped students' mental category boundaries more powerfully than the abstract legal rule itself.

Principle

Which principle for Customer Experience Design can be derived from this? The core principle is: Examples shape expectations—show the full range, not just the ideal. Customers form their understanding of a product or service primarily through concrete examples, so the selection of exemplars shown largely determines what they perceive as possible and typical. Companies should therefore deliberately present a representative diversity of use cases, user profiles, and outcomes to set realistic expectations and maximize perceived relevance. This is especially critical for innovative products or services where customers lack established category concepts—in these cases, a few well-chosen examples can define the entire market. The following guidelines demonstrate how to apply this principle in practice.

Guidelines

Demonstrate diversity in use cases

Present deliberately diverse examples of product usage and customer profiles. Avoid showcasing only the ideal case or a homogeneous user group. A SaaS tool shouldn't feature only tech startups—include SMEs, non-profits, and sole proprietors as well. An insurance company shouldn't show only young families—represent singles, seniors, and self-employed individuals too. The range of examples determines who feels addressed and what seems possible. The more diverse the examples, the broader the mental category.

Omit examples of non-target audiences

Negative examples ("Not suitable for...") can unintentionally narrow category perception. Explicitly stating "Our software is not for small teams under 10 people" makes this boundary more salient than necessary. Better approach: Show positive examples of your target audience without mentioning non-target groups. Exception: When the distinction is purchase-critical, such as technical requirements. In these cases, frame it as a factual requirement ("Requires SQL knowledge") rather than a negative example ("Not for SQL beginners").

Initial contact with representative specimen

The first example shown becomes the mental anchor for the entire category. In product demos or website content, the initial example should be deliberately chosen: Does it demonstrate the core function? Does it appeal to the primary target audience? Is it neither too simple nor too complex? A CRM tool that first shows an enterprise setup with 50 custom fields will lose small and medium-sized business customers. One that starts with a two-person team will deter corporations. The entry example should match the median complexity of the target audience.

Leading from the concrete to the abstract

Begin with concrete examples, then transition to the abstract principle. "Customer A uses it this way, Customer B uses it differently—the underlying principle is..." This sequence harnesses the strength of examples (comprehensibility) while avoiding their weakness (overly narrow interpretation). Relying solely on example-based communication forces customers to extract the principle themselves, which may lead them to derive the wrong rule. Explicitly stating the abstraction after presenting multiple examples corrects their mental model and enables them to transfer the concept to new situations.