How Cognitive Biases Like Hyperbolic Discounting and the Peak‑End Rule Shape Better Product Design

As humans we are not always rational; social psychology shows that perception and decision‑making are often biased. Designers can deliberately exploit these biases to craft better products.

01 Hyperbolic Discounting

In 1984 economist Mazur proposed that our brains struggle with lengthy information because uncertainty grows with more data, causing perceived value to decline over time. Consequently, people tend to down‑weight long‑term benefits or costs, treating distant outcomes as less important.

For example, banks may promise future premium services to attract credit‑card applicants, but many users are swayed by immediate gifts such as luggage or kitchen sets. Similarly, many internet products offer first‑month discounts or free trials to provide instant value and boost conversion.

02 Peak‑End Rule

Nobel laureate Daniel Kahneman’s peak‑end rule states that people evaluate an experience based on its most intense moments (the "peak") and its final moments (the "end"). The brain records only the most salient points, not the entire experience.

IKEA exemplifies this rule: while the shopping journey includes long queues and sparse staff, the store creates pleasant peaks (comfortable sofas, cheap accessories, thoughtful pencils) and ends the visit with free ice‑cream and hot‑dogs, leaving a positive overall memory.

Game designers also apply the rule; for instance, the Switch game "Ring Fit Adventure" delivers continuous encouragement (peaks) and a ceremonious ending pose (end) that boosts player satisfaction.

03 Futile Curve

In a rental‑app scenario, users select several apartments and use a "viewing route" feature that plans an optimal order with navigation cues. After launch, both usage frequency and depth were disappointing.

Research revealed high uncertainty: users often change plans mid‑tour, interrupting the intended sequence. They also expect navigation quality comparable to dedicated map apps (Gaode, Baidu). When the product fails to meet these expectations, the cognitive bias of over‑estimated expectations harms satisfaction.

The "futile curve" visualizes design effort (x‑axis) versus user satisfaction (y‑axis). Satisfaction rises with effort up to a point, then drops sharply (the futile zone), before climbing again when effort reaches a breakthrough level.

Designers should aim for a reasonable effort range, align user expectations, and provide sufficient resources to achieve peak experiences.

These three curves expose common cognitive biases; when applied thoughtfully, they enable designers to achieve disproportionate impact with modest effort.

Reference: "Designing Better Products with 84 Cognitive Biases" (original author @gilbouhnick, translator Jiang Wuzha) and "The Conspiracy Behind IKEA’s One‑Dollar Ice Cream" by Lao Zu.