How food manufacturers get away with changes like this
In his book Priceless: The Hidden Psychology of Value, William Poundstone writes that consumers might switch peanut butter brands if the price goes up. But if the price stays the same and the jar invisibly shrinks? No harm, no foul. That's why in 2008, Poundstone notes that Kellogg's also made thinner cereal boxes of Cocoa Krispies, Froot Loops, and Apple Jacks, but kept the width, height, and price the same... and no one noticed.
No one is looking at the label of a cereal box or a peanut butter jar to see how much food is in there. You trust your eyes and the price you've seen over and over again. That's how companies can get away with this.
But those changes were in 2008. What's going on in the peanut butter game today?
Peanut butter companies don't want to talk about this
I reached out to Hormel, which has owned Skippy since 2013. Back in 2008, when the jar changes were made, Unilever owned it. I asked why the peanut butter jar has a dimple, and if the shape has changed recently. Hormel didn't respond to my question, but a spokesperson did say that, "We have not changed the jar since we acquired the brand in 2013."