The case
Ask around and you'll hear confident memories of the Jiffy jar, and of the moment it "changed" to Jif. The jar never changed. The peanut butter was introduced as Jif and has never carried another name.
Two neighbors on the shelf explain the mix-up. Jiffy corn muffin mix has been in the same aisle since 1930, and Skippy peanut butter shares the shape and the vowel sound. Jif plus Skippy, said quickly, is Jiffy.
Why our brains do this
A blend of two real brand names produces a third that feels real. The word "jiffy" already exists in English, which makes the blend even stickier.
Sources: Wikipedia — Jif (peanut butter) · Wikipedia — Jiffy mix · Wikipedia — False memory: the Mandela effect
