Involuntary memory

Involuntary memory, also known as involuntary explicit memory, involuntary conscious memory, involuntary aware memory, and most commonly, involuntary autobiographical memory, is a subcomponent of memory that occurs when cues encountered in everyday life evoke recollections of the past without conscious effort. Voluntary memory, its binary opposite, is characterized by a deliberate effort to recall the past.

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.

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. The term "precious fragments" was coined by Marigold Linton, a pioneer in the study of autobiographical memory research.

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."

Finally, some involuntary memories arise from traumatic experiences, and as such are fairly rare compared to other involuntary memories. Subjects describe them as salient, repetitive memories of traumatic events. The troubling nature of such memories makes these occurrences important to clinical researchers in their studies of psychiatric syndromes such as Post-traumatic Stress Disorder.

Born in Bremen, Germany in 1850, Hermann Ebbinghaus is recognized as the first to apply the principles of experimental psychology to studying memory. He is especially well known for his introduction and application of nonsense syllables in studying memory. Nonsense syllables are combinations of letters that do not follow grammatical rules, and are meant to lack any meaning. Ebbinghaus designed the use of them to study his own memory by memorizing lists of nonsense syllables and testing his own recall after specified time intervals. From this he discovered the Forgetting curve and the Spacing effect, two of his most well-known contributions. Ebbinghaus was also the first to attempt a description of involuntary memory, stating that, ‘Often, even after years, mental states once present in consciousness return to it with apparent spontaneity and without any act of the will; that is, they are reproduced involuntarily. Here, also, in the majority of cases we at once recognize the returned mental state as one that has already been experienced; that is, we remember it. Under certain conditions, however, this accompanying consciousness is lacking, and we know only indirectly that the "now" must be identical with the "then"; yet we receive in this way a no less valid proof for its existence during the intervening time. As more exact observation teaches us, the occurrence of these involuntary reproductions is not an entirely random and accidental one. On the contrary they are brought about through the instrumentality of other immediately present mental images. Moreover, they occur in certain regular ways that, in general terms, are described under the so-called laws of association.

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