Availability heuristic

We judge how likely or common something is by how easily examples come to mind.

Tversky & Kahneman (1973), Availability: A heuristic for judging frequency and probability.

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What is Availability heuristic?

Availability heuristic is a behavioural bias (judgement family): we judge how likely or common something is by how easily examples come to mind. Vivid stories, recent news and testimonials make outcomes feel more common than they are. Nudgeswipe rates the evidence as strong. Source: Tversky & Kahneman (1973), Availability: A heuristic for judging frequency and probability.

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The research

Vivid stories, recent news and testimonials make outcomes feel more common than they are. Products show it in "people like you just…" feeds and case-study carousels.

● 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/10.1016/0010-0285(73)90033-9

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Key takeaways

Honest nudge
Use real, representative examples and give base rates alongside the story.
Dark-pattern line
Featuring rare best-case outcomes so they look typical (e.g. one customer's windfall as the headline).
Grey-area example: ZOE leads with first-name member quotes and "world-leading science" →

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: Availability heuristic (Judgement, strong evidence): We judge how likely or common something is by how easily examples come to mind.
How it works: Vivid stories, recent news and testimonials make outcomes feel more common than they are. Products show it in "people like you just…" feeds and case-study carousels.
Source: Tversky & Kahneman (1973), Availability: A heuristic for judging frequency and probability. https://doi.org/10.1016/0010-0285(73)90033-9
Honest use: Use real, representative examples and give base rates alongside the story.
Dark-pattern line: Featuring rare best-case outcomes so they look typical (e.g. one customer's windfall as the headline).
Page: https://nudgeswipe.com/biases/availability-heuristic/ (JSON: https://nudgeswipe.com/api/biases/availability-heuristic.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 availability heuristic 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 Availability heuristic?

Availability heuristic is a behavioural bias: we judge how likely or common something is by how easily examples come to mind.

How does Availability heuristic work?

Vivid stories, recent news and testimonials make outcomes feel more common than they are. Products show it in "people like you just…" feeds and case-study carousels.

How strong is the evidence for Availability heuristic?

Nudgeswipe rates it strong evidence (provisional). Original source: Tversky & Kahneman (1973), Availability: A heuristic for judging frequency and probability.

How can you use Availability heuristic honestly?

Use real, representative examples and give base rates alongside the story.

When does Availability heuristic become a dark pattern?

Featuring rare best-case outcomes so they look typical (e.g. one customer's windfall as the headline).

Which brands use Availability heuristic?

Nudgeswipe has 2 teardowns of brands using it, including ZOE, Trading 212. Whether it lifted their results is not public unless a teardown cites it.

In the wild

2 real examples

zoe.com

ZOE Homepage screenshot, captured 16 Oct 2026

Social proofGrey area

ZOE leads with first-name member quotes and "world-leading science"

ZOE · Homepage

trading212.com

Trading 212 Homepage screenshot, captured 16 Oct 2026

Availability heuristicGrey area

Trading 212 shows a sample "Your earnings" widget from share lending, under a risk warning

Trading 212 · Homepage

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