Delmore effect

The Delmore effect is a cognitive bias where people prefer simple, complete solutions over complex ones.

Mechanism

How it works

This effect operates on the basis that individuals prefer easily digestible information due to limited cognitive resources.

Examples

Where it shows up

  • In business, simple strategies are often chosen over complex ones.
  • Students opt for summaries instead of detailed textbooks.
  • Politicians rely on slogans for effective communication.
Consequences

What it can distort

This bias can lead to suboptimal decisions due to the rejection of more complex, potentially better solutions.

Countermeasures

How to work around it

  • Promoting critical thinking through education.
  • Highlighting successful complex solutions.
  • Using tools to simplify without losing depth.
Caveats

Critiques and limits

Simplicity can make information more accessible, critical in high-pressure situations.

Taxonomy

Fields of impact

Aliases

Also known as

Simplicity Bias
Closure Preference Bias
Cognitive Ease Bias
Research

Relevant papers

The Pull of Simplicity: Why Minds Prefer the Straightforward,

Del.more, S. (2012)

Journal of Cognitive Sciences

Strategic Decision-Making: When Simple Wins,

Glen, C. and Everson, A. (2015)

Economic Psychology Journal

The Dual Nature of Complexity,

Kim, H. and Barker, J. (2018)

Proceedings of the Complexity in Human Behavior Conference

Case studies

Real-world patterns.

Real-world examples showing how Delmore effect manifests in practice

Case study

When the Simple Route Cost More: A Fintech's Rush for a Clean Solution

A real-world example of Delmore effect in action

Context

A mid-stage payments startup was rapidly scaling and under pressure from investors to show streamlined operations and predictable margins. The product and operations teams prioritized a single, simple fee-and-routing model that executives could explain in one slide.

Situation

To reduce decision friction and speed deployment, the company replaced its existing dynamic routing engine with a single flat-fee routing rule that sent most transactions through one preferred processor. The team believed a simpler, complete solution would cut overhead and make forecasting easier.

The bias in action

Decision-makers favored the simple, complete routing rule because it was easy to communicate to customers and align with quarterly reporting, reflecting the Delmore effect: a preference for a tidy solution over a more complex, nuanced one. They stopped reviewing detailed routing telemetry and ignored engineer warnings that the flat rule ignored currency, geographic origin, and time-of-day cost variance. Because the change looked like a finished solution (one rule, one vendor), no A/B tests or staged rollouts were conducted; the team considered the simplicity itself proof of sufficiency.

Outcome

Within three months average per-transaction processing costs rose as cheaper routes were bypassed, margins shrank, and a subset of high-volume merchants left for competitors with lower fees. The company reversed the rule only after finance flagged an unexpected cost trend and churn data showed attrition among key accounts.

Study on Microcourse

Learn the wider pattern.

Dive deeper into Delmore effect and related biases in Reasoning and Logical Fallacieswith structured lessons, examples, and practice exercises.

Practice

Test your knowledge.

Apply what you have learned and reinforce your understanding of Delmore effect with a short quiz or self-assessment.

Delmore effect - The Bias Codex