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. Some researchers have found that involuntary memories tend to have more emotional intensity and less centrality to life story than voluntary memories do. However, one study also shows that recurrent involuntary memories post-trauma can be explained with the general mechanisms of autobiographical memory, and tend to not come up in a fixed, unchangeable form. This suggests that psychologists may be able to develop ways to help individuals deal with traumatic involuntary memories. Implications for Dementia Patients Further research on the automatic nature of involuntary retrieval suggests that they may not require working memory input. Thus, one report hypothesizes that dementia patients may still have available precious autobiographical memories that remain inaccessible until “suitable triggers release them,” prodding at the possibility for caregivers to be trained to reactivate these memories to elicit positive emotional effects and maintain patients’ life stories and sense of identity. Further empirical research is needed, but this insight starts a hopeful path into improving dementia care. History Hermann Ebbinghaus 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, study of which led him to discover the forgetting curve and the spacing effect, two of his most well-known contributions to the field. 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." He goes on to explain that these mental states were once experienced, rendering, by definition, their future spontaneous appearance into consciousness the act of remembering, though we may not always be aware of where or how we experienced this information the first time. Ebbinghaus also made the key note that these involuntary reproductions are not random or accidental; instead, "they are brought about through the instrumentality of other immediately present mental images," under the laws of association. This reflects congruence with Mace's and Linton's theory of involuntary memories as by-products of other memories, as discussed above. Marcel Proust—Proustian memory Marcel