Restorff Effect
In 1933 Hedwig von Restorff discovered that: Isolating an item against a crowded or homogenous background facilitates the learning of that isolated item. [1] This is often called the isolation effect, and it is useful when designing mnemonics.
Wallace, W. P. (1965). Review of the historical, empirical and theoretical status of the von Restorff phenomenon. Psychological Bulletin, 63, 410–424. ↩︎