Confirmation bias

We look for, notice and remember evidence that fits what we already believe.

Wason (1960), On the Failure to Eliminate Hypotheses in a Conceptual Task.

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What is Confirmation bias?

Confirmation bias is a behavioural bias (judgement family): we look for, notice and remember evidence that fits what we already believe. Users skim reviews and comparisons for support of the option they already lean towards; teams read A/B results the same way. Nudgeswipe rates the evidence as strong. Source: Wason (1960), On the Failure to Eliminate Hypotheses in a Conceptual Task.

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The original study

Wason (1960), On the Failure to Eliminate Hypotheses in a Conceptual Task.

What the paper reports: In Wason's number-rule task, most of 29 participants announced at least one wrong rule; those with two or more wrong rules were unable or unwilling to test their hypotheses.

Summarised from the paper's abstract.

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The research

Users skim reviews and comparisons for support of the option they already lean towards; teams read A/B results the same way.

● Strong evidence (provisional)

Provisional rating: we cite only the original paper so far. It stays provisional until a replication or meta-analysis is added.

Source: doi.org/10.1080/17470216008416717

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Key takeaways

Honest nudge
Show the downsides and the fit criteria up front, so people can check rather than just confirm.
Dark-pattern line
Curating only agreeing reviews or comparisons so a shopper's first impression is never challenged.

Use it

Apply this with your agent

The prompt carries this bias, its evidence rating and the honest-vs-dark line.

You are helping me apply a behavioural bias ethically in my product.

Bias: Confirmation bias (Judgement, strong evidence): We look for, notice and remember evidence that fits what we already believe.
How it works: Users skim reviews and comparisons for support of the option they already lean towards; teams read A/B results the same way.
Source: Wason (1960), On the Failure to Eliminate Hypotheses in a Conceptual Task. https://doi.org/10.1080/17470216008416717
Honest use: Show the downsides and the fit criteria up front, so people can check rather than just confirm.
Dark-pattern line: Curating only agreeing reviews or comparisons so a shopper's first impression is never challenged.
Page: https://nudgeswipe.com/biases/confirmation-bias/ (JSON: https://nudgeswipe.com/api/biases/confirmation-bias.json)

Rules: say a brand "uses" a tactic, never that it "worked"; outcomes are not public unless the company published them; no invented uplift estimates; flag mixed evidence. Honest nudge = true, visible, easy to reverse, and in the user's interest. Dark pattern = hides costs, fakes scarcity or popularity, shames, or makes leaving harder than joining. Quote company-published results as "X reports", with the source link, and don’t generalise them. Don’t cite retracted or failed-to-replicate studies as support (e.g. Ariely & Wertenbroch 2002). Don’t state study figures unless they’re on this page or in a source you can link. If an idea crosses the line, link the matching deceptive.design pattern.

Tasks:
1. Ask me for my product, the flow and the goal.
2. Audit where confirmation bias already shapes that flow, for better or worse.
3. Propose 2-3 ethical experiments: hypothesis, variant, primary metric, guardrail metric.
4. Flag dark-pattern risks. The rating is provisional: no replication or meta-analysis is cited yet.

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Frequently asked questions

What is Confirmation bias?

Confirmation bias is a behavioural bias: we look for, notice and remember evidence that fits what we already believe.

How does Confirmation bias work?

Users skim reviews and comparisons for support of the option they already lean towards; teams read A/B results the same way.

How strong is the evidence for Confirmation bias?

Nudgeswipe rates it strong evidence (provisional). Original source: Wason (1960), On the Failure to Eliminate Hypotheses in a Conceptual Task.

How can you use Confirmation bias honestly?

Show the downsides and the fit criteria up front, so people can check rather than just confirm.

When does Confirmation bias become a dark pattern?

Curating only agreeing reviews or comparisons so a shopper's first impression is never challenged.

In the wild

No teardown yet

We haven't captured a real product or email using confirmation bias yet. Seen one? Use the prompt above to audit your own flow, or browse all teardowns.

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