Two numbers on the front of a jar. Cost to us: $2.10. What we added: 90c. The first feeling is admiration, because nobody else in the aisle shows you this. The second feeling arrives a beat later, slightly against your will, carried by arithmetic that does itself: 90 cents on $2.10 is a 43% markup. On peanut butter. And with that, the most honest label in the shop has produced the exact feeling it was built to prevent: the faint, unmistakable sense of being had.
The honesty that should work
The case for printing the markup is strong, and I believed all of it. Admit the thing everyone assumes you are hiding, and the admission does your persuading for you: Guinness turned the slow pour, the least convenient thing about the product, into the entire advertisement. A grocer that says, out loud, here is what we make on this jar, is running the same play, converting suspicion into confession and confession into credibility. The play looks especially strong here, where most of the aisle belongs to a duopoly whose regulator has found that competition is not working well for consumers (Commerce Commission 2022). Against that backdrop, the shop that shows its working looks like the only honest player in the room, and the whole appeal rests on one assumption: that transparency and trust are the same thing.
They are not, and a 40-year-old experiment marks the exact point where they part.
The number is also an anchor
In 1986 Kahneman, Knetsch, and Thaler put pricing scenarios to ordinary people and asked one question of each: fair or unfair? The famous one is a hardware store that has been selling snow shovels for $15 and raises the price to $20 the morning after a big snowstorm. 82% called it unfair (Daniel Kahneman 1986). Not unaffordable: unfair. The rise violated a norm about what a seller is entitled to. People carry a rough reference transaction in their heads, a sense of what a thing usually costs and what a seller may reasonably take, and they police prices against it without ever being able to say where the line sits. The researchers called the norm dual entitlement: the buyer is entitled to the terms they are used to, the seller to a reasonable profit, and the shopper patrols the border between the two.
Now run the honest jar through that finding. While the markup is invisible, the 90 cents is folded into a single number, $3.00, and $3.00 gets judged the only way it can be: against every other jar of peanut butter you have ever bought. Print the cost beside it and you have changed the contest. The 90 cents is no longer judged against other jars. It is judged against the $2.10 it sits on, and against a fair-markup norm you did not know you carried until a printed number invited you to apply it. The revealed cost is not neutral information. It is a reference point, and a reference point is a thing people measure you against.
This is the part the transparency pitch skips. You do not get to show a number and control which comparison it triggers. Everlane built a clothing brand on exactly that gamble, a printed cost breakdown under every garment, materials and labour and transport laid bare, and the honesty was real and widely admired, and admiration did not rescue the business: the company slid from its peak and survives in reduced circumstances. The unresolved question was never whether the numbers were true. It was which frame won at the shelf: look how little we take, or look how much they add.
The safer anchor
So the design problem for a grocer built on showing its working is not honesty versus secrecy. It is which comparison the honesty sets up. A capped, modest, permanent margin is a fair deal on any reading of dual entitlement; whether it feels fair depends on the anchor beside it, and a printed cost anchors the shopper to the one comparison that makes 90 cents read as greed. The fix is not less honesty. It is a different anchor.
Put your whole price next to what the same jar costs at the duopoly down the road, and the contest changes again. The shopper is no longer weighing your 90 cents against your $2.10. They are weighing your $3.00 against the other shelf, and the revealed markup flips from suspect to hero. The number to print, in other words, is not your cost. It is their price. Same transparency, opposite reference point, opposite feeling.