Involuntary memory, also known as involuntary explicit memory, involuntary conscious memory, involuntary aware memory, madeleine moment, mind pops and most commonly, involuntary autobiographical memory, is a sub-component of memory that occurs when cues encountered in everyday life evoke recollections of the past without conscious effort. Voluntary memory, its opposite, is characterized by a deliberate effort to recall the past. Occurrences There appear to be at least three different contexts within which involuntary memory arises, as described by J.H. Mace in his book Involuntary Memory. These include those that occur in everyday life, those that occur during the processes of voluntary and involuntary recall, and those that occur as part of a psychiatric syndrome. Precious fragments These include involuntary memories as they arise in everyday mental functioning, comprising the most common occurrences. They are characterized by their element of surprise, as they appear to come into conscious awareness spontaneously. They are the products of common every-day experiences such as eating a piece of cake, bringing to mind a past experience evoked by the taste. Research suggests that such experiences are especially strong and frequent in relation to one's sense of smell. The term "precious fragments" was coined by Marigold Linton, a pioneer in the study of autobiographical memory research. This is reflected, for example, in Proust's experience of remembering, upon dunking a madeleine cake in his tea in adulthood, a memory from childhood that occurred while eating madeleine dunked in tea. By-products of other memories These are less common, and appear to be the result of voluntary/involuntary retrieval. Characteristic of such occurrences is the triggering effect this has, as one involuntary memory leads to another and so on. Again, Linton describes her own experiences with such memories as "coming unbidden sometimes when my mind is silent, but also as by-products of searches for other information." Mace terms these “involuntary memory chains,” stating that they are the product of spreading activation in the autobiographical memory system. These involuntary retrievals are experienced when activations are strong or relevant enough to current cognitive activity that they come into consciousness. According to Mace, this suggests that autobiographical memories are organized primarily conceptually (“experiential type concepts: people, places, locations, activities, etc.”), while temporal associations are not retained over time the same way. Not so precious fragments Finally, some involuntary memories arise from traumatic experiences, and as such are fairly rare compared to other involuntary memories. Subjects