As the Christmas trees accumulate on the sidewalks and the college students give up their languorous breaks and return to school, I would like to take one last backward look at 2008 and say good-bye to a man who contributed more to our understanding of human
memory than any other individual who has ever lived. He was not a scientist; he was not a Proustian scholar; he was not a writer or artist.
Henry Molaison (or H.M. in the scientific literature) died on Dec. 2nd 2008 at the age of 82, in a nursing home outside Hartford, CT (http://www.nytimes.com/2008/12/05/us/05hm.html). He was a motor mechanic who had been hit by a bicycle at the age of 9 and soon after developed debilitating seizures. At the age of 27, increasingly incapacitated by these convulsive episodes, he sought relief from the neurosurgeons of Hartford Hospital. There, in an effort to tame the seizures, Dr. William Beecher Scoville removed critical sections of his brain's medial temporal area, including the sea horse-shaped hippocampus. The rest, as they say, is history, or in H.M.'s case, the lack of any history from that point forward.
What happened to H.M. and what changed our understanding of memory is that without these portions of his brain intact, H.M. could not consolidate new memories. The gist of his life and well-learned routines acquired before his current age were still available to him. He could remember some general events from his childhood (e.g., hiking trips, going to the beach); he could remember some details of his work; he could remember a few major world events. He could make his bed, do simple chores, glance at a paper, fix a sandwich. However, any new events, new conversations, new information had a retention time of roughly 15 minutes and then it was gone, lost to his consciousness, as fleeting as a passing breeze.
With those few strokes of his surgical instruments, Dr. Scoville had inadvertently created the greatest living laboratory for the study of human memory that has ever existed. Affable, compliant, and healthy as a horse, H.M. lived on and on. And the legion of researchers made their pilgrimages to Hartford with their memory tests, drawing pads, and learning lists. They came to understand the vital role that the medial temporal region plays in transferring encoded information to higher areas of the brain - how it enables the linkage of new memories to concepts and categories in the cerebral cortex that allow them to be slotted and safely stored. The fact that H.M. could retain some new information after sufficient repetition, but only in a vague and routinized manner without any conscious awareness of what he had learned, also taught these researchers about the existence of two memory systems - one for explicit or "declarative" memory and the other for implicit or "procedural" recall. Now with MRI technology and sophisticated memory tests, neuroscientists are honing in on the exact roles that the hippocampus and related structures, such as the anterior cingulate nucleus, and the amygdale play in memory. However, it was H.M.'s unfortunate mishap that shone the spotlight for the first time on these vital organs of recall. So neuroscientists and memory researchers owe him an immeasurable debt. But this is not all he taught us and this why I, as a personality and clinical psychologist, want to express my own personal tribute.
H.M. is more than just an iconic figure in memory. His odd and tragic-comic 55 years of unexamined living (unexamined by him, but scrupulously examined by others) have spoken eloquently to us about the meaning of self and identity. H.M. went on living, eating, talking, smiling, laughing, but he remained frozen in a Rip Van Winkle twilight of his first 27 years. He could not accumulate experience, accrue the wisdom of lessons learned, savor the passage from anxious youth to the comforts of his later years, nor (perhaps thankfully) face the despair of lost chances and unfulfilled opportunities. The novel of his life stopped and never resumed. As a consequence, his narrative identity, what Dan McAdams calls the "life story" (McAdams, D. P. (2001). The psychology of life stories. Review of General Psychology, 5, 100-120.) could not knit together his past, present, and future into a unified and purposeful whole. Like the cat that chases his tail or the dog who relishes with surprise the very same bone he himself has hid, H.M. greeted familiar visitors as new friends and could comfortably carry out the same conversation each day in an endless recursive loop.
There is no indication that H.M. lived an unhappy life. In a sense his salvation was his inability to grasp what he had lost or put more precisely, what he could never accrue. For the rest of us, his one dimensionality - his perpetual present - reminds us of what we owe to memory - of how fully and richly we know ourselves from what has transpired in our past. Years ago I wrote a book with Peter Salovey (Singer, J. A., & Salovey, P. (1993). The remembered self. New York: The Free Press.) that championed the thesis that we selectively construct our personalities from certain key "self-defining memories." Yet the emotional power of these memories was not paradoxically based in the original experiences, but in the relationship of these past events to our current goals and desires. What defines key memories as central to our sense of self is their ongoing relevance to what we are actively seeking and pursuing in our current lives. Freud felt that our early experience was determinative of our future desire. We argued that equal weight be given to the reciprocal influence of the present on the past. Identity is a circling dance between now and then that culminates in "What if?"
Dr. Scoville severed the relationship between present and past for H.M. and in doing so he robbed him of the capacity to look forward. And this is the real secret of what H.M. taught us about identity and not just memory. From the standpoint of personality, H.M.'s most profound loss was the future not the past. In every memory lives a dream or a nightmare - if this is what happened before, how can I have this again or how can I make this different? Life is janus-faced - without the backward glance, there is no knowledge of the distance still to go. We simply run in place. With the gift of memory, we are able to put in place the chapters of our story and construct a plot that pulls us toward a still unresolved ending. The plot propels us forward, demanding at each turn that we ask, "What will happen next?" Memory is indeed the engine of identity.
So good-bye and thank you, H.M.! You have left a legacy of research and understanding of which you were only dimly aware. It is now our duty to take the strange present that your life offered to us and apply it to a more complex and humane vision of ourselves.
