Our memories are of complex patterns of stimuli-not of individual stimuli in isolation of each other. An image of a face is one such pattern, a melodic refrain is another. It is as if the pieces of a pattern are linked to or associated with each other so that awareness of a critical number of pattern elements or pieces activates the links to restore or recall the entire pattern. Attention to a distinctive scar can cause us to recall the appearance of a face encountered in the past. Hearing a few notes in a particular sequence may trigger a memory of a symphonic movement.