Design for Short-Term Memory

Short-term memory acts as a kind of buffer to long-term memory, capable of holding at most 5-9 short "chunks" of information. Buffer capacity decreases with item complexity, holding, e.g., only 3-4 unrelated items. Capacity also decreases with age, declining most sharply after age 55. Dynamic variations in capacity depend on the structural allocation of mental resources among active processes. Reduced short-term memory load allows for higher mental processing; overloading results in frustration and fatigue.