“Skippy peanut butter recently redesigned its plastic jar. “The jar used to have a smooth bottom,” explained Frank Luby, a price consultant with Simon-Kucher & Partners in Cambridge, Massachusetts. “It now has an indentation, which takes a couple of ounces of peanut butter out of the product.” The old jar contained 18 ounces; the new has 16.3. The reason, of course, is so that Skippy can charge the same price.
That dimple at the bottom of the peanut butter jar has much to do with a new theory of pricing, one known in psychology literature as coherent arbitrariness. This says that consumers really don’t know what anything should cost. They wander the supermarket aisle in a half conscious daze, judging prices from cues, helpful and otherwise. Coherent arbitrariness is above all a theory of relativity. Buyers are mainly sensitive to relative differences, not absolute prices. The new Skippy jar essentially amounts to a 10 per cent increase in the price of peanut butter. Had they just raised the price 10 per cent (to $3.39, say), shoppers would have noticed and some would have changed brands. According to the theory, the same shopper would be perfectly happy to pay $3.39 for Skippy, just as long as she doesn’t know there’s been an increase.”