2. Chronological systems (using complex in a rather extended sense) are those which embrace the experiences of certain epochs of our lives rather than the subject material included in them. In a general way events as they are successively experienced become associated together, and with other elements of personality, so that the later recollection of one event in the chain of an epoch recalls successively the others. Conversely a break in the chain of memory may occur at any point and the chain only be picked up at a more distant date, leaving between, as a hiatus, an epoch for which there is amnesia of reproduction. This normally common amnesia affords confirmatory evidence of the associative relation of successive events. Involving as it does the unimportant and unemotional experiences as well as the important and emotional—though the former may be as well conserved as the latter—it is not easy to understand. The principle, however, plays an important part in abnormal amnesia particularly, but not necessarily, where there is a dissociation of personality.
The epoch may be of a few hours, or it may be of days, of months, or years. The simplest example is the frequent amnesia for the few hours preceding a physical injury to the head resulting in temporary unconsciousness. In other cases it is the result of extensive dissociation effected by suggestion (e. g., in hypnosis), or psychical trauma including therein emotional conflicts. Thus, to cite an experimental example: Miss B. is troubled by a distressing memory which constantly recurs to her mind during the twenty-four hours. To relieve her I suggest that she will completely forget the original experience. To my surprise, though the suggestion is limited to the experience alone, the whole twenty-four hours are completely wiped out of her memory. She cannot recall a single incident of that day. The whole epoch which had associations with the memory is dissociated.
When the epochal amnesia follows psychical trauma the condition of memory is apt to present the following peculiarity and the personality may be altered. When the epoch is the immediate past, i.e., includes the experiences extending from a certain past date up to the present, it sometimes happens that memory reverts to that past date. That is to say, the personality goes back to the period last remembered in which he believes, for the moment, he is still living, the memory of the succeeding last epoch being dissociated from the personal consciousness. Under such conditions there is something more than amnesia. The neurographic residua of the remembered epoch are revived and its experiences remembered as if they had just been lived. There is not only a dissociation of the memories of one epoch, but a resurrection of the conserved and maybe forgotten experiences of a preceding one. The synthesis of these memories restores again the personal consciousness of that period. Before the cleavage took place the recollection of the resurrected epoch may have been very incomplete and vague; afterward the new personality remembers it as if just experienced. The personality is, however, in other respects generally (always?) something different from the personality of that particular epoch. The dissociation is apt to involve a certain number of acquired traits and certain innate dispositions and instincts, while other outlived and repressed traits and innate dispositions and instincts are apt to be reawakened and synthesized into an altered abnormal personality. But this is another story that does not concern us now.
As an example of epochal amnesia I may cite Mrs. J——, who, after dissociation occurs, has amnesia for all the events of several years succeeding a certain hour of a certain day when a psychical trauma (shock) occurred. She thinks she is living on that day and remembers in great detail its events as if they had just occurred.
Miss B. reverts on one occasion to a day, six years back, when she received a psychical shock; the complexes of her personality of that day are revived as if just lived, all the succeeding years being forgotten; on another occasion she reverts to a day when she was living in another city seven or eight years before.
M——l reverts to an early period of his life when he was living in Russia, and forgets all since including even his knowledge of English.
B. C. A. on several occasions reverts to different epochs of her life with complete amnesia for all after events. On each occasion she takes up the thread of her mental life as if living in the past, and recites the events as if just lived.
Likewise, after a subject reverts from the abnormal to the normal state, after a short or long condition of altered personality, there may be a complete amnesia for the abnormal epoch, and although now normal he thinks it the same day on which dissociation occurred.
Thus, Miss O. develops a condition of dissociated personality lasting six months during which, as it unfortunately happens, she falls in love with a man whom she had never known in her normal state. At the end of this period she “wakes up” with a complete loss of memory for the phase of altered personality and, therefore, to find that her fiancé is apparently a stranger to her (!).
The same amnesia in the normal state for prolonged epochs in which the personality was altered was conspicuous in the case of Miss B. In William James’ often-cited case of Ansel Bourne and Dr. E. E. Mayer’s case of Chas. W. the subjects returned to their normal states with complete amnesia for the abnormal epochs of two months and seventeen years respectively.