Technique · Influence
Find and back the deciding cue
Identify the one element most buyers act on at a conversion point (a price, a rating, a badge, the word "free", a logo) and make sure the substance behind it is always present. Under load, decisions hinge on one cue, so that cue deserves the most care.
Plain label: deciding-cue auditAlso known as: trigger feature, cue validity, click, whirr, single-cue decision, decision driver
How it works
In recurring decisions people respond to a single salient feature rather than the whole offer, because that feature usually travels with the real thing. A cue that shows up without its substance converts once and then teaches users to distrust it. Knowing which cue carries the decision tells a team where a small change in accuracy, placement or wording will matter most.
In the book. Animals and people respond to one trigger feature of a situation, and the response is usually right because the feature normally comes with the real thing (Ch.1, pp.2-3, 7). INF-T-FN-02 (Influence Ch.1, p.2)
In a product [S]. Find the cue people act on at each conversion point, then write a rule that guarantees the substance whenever the cue shows. In the decision-point lens this is what separates coverage 3 from coverage 2: the deciding cue is identified and backed.
Evidence Evidence grade C. Limited evidence: few or small studies.. The model is well grounded; the book's product examples are anecdotes.
Evidence warning
These are single anecdotes; use them to choose what to measure, not as effect sizes.
What the research says
A shop's slow-selling turquoise sold out after a note meant to halve the price was read as doubling it; buyers who could not judge the stones read the higher price as quality.
Influence Ch.1, pp.1, 4-5
Misprinted tire coupons that offered no saving drew as many buyers as correct ones: the coupon's form, not the saving, did the work.
Influence Ch.1, pp.5-6
Before you start
- Decision-driver survey answers or click data from the conversion page
How to build it
- Web
- Add a one-question post-purchase survey ("What made you decide today?") listing the page's cues, and read it next to last-click data. Fix the top cue first: real counts, a date on ratings, a badge that links to its criteria.
- E-commerce
- Audit every badge and label on product pages ("Bestseller", "Sale", the star rating) against a written rule that guarantees the substance, and remove labels that can appear without it.
- B2B
- Ask closed-won and closed-lost buyers which single item settled the decision (the security report, a customer logo, the price) and make that item easy to verify.
What can go wrong
- Polishing a cue that is not the deciding one; measure before redesigning.
- A cue that sometimes appears without its substance (a "Bestseller" badge on a new item) erodes every badge on the site.
Pairs well with
- Pairs with in-t-sp-12: once the deciding cue is known, put honest proof next to it.
- Pairs with in-t-ep-03 on mobile and at checkout, where people lean hardest on one cue.
In practice
Where it shows up
Sources
Influence · Robert Cialdini
Ch.1, p.2 · Ch.1, p.7
Source IDs: INF-T-FN-02
Book content is paraphrased, never quoted at length. Last verified October 24, 2026.
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