Oh, look. How sad. H.M., the famous amnesiac, has died at the age of 82.
As a result of an experimental brain operation in 1953 to address a seizure disorder, H.M. lost not only most of his existing memory but his ability to form new memories. Those of you who saw the film Memento are familiar with the syndrome - anything new that happens is forgotten within about 20 seconds, so that every experience in the world seems new; the world is constantly refreshing itself.
"He was recognized as the most important patient in the history of brain science. As a participant in hundreds of studies, he helped scientists understand the biology of learning, memory and physical dexterity, as well as the fragile nature of human identity."
By studying his mind, scientists saw that there were at least two systems in the brain for creating memories. One, known as declarative memory, records names, faces and new experiences, and stores them until they are consciously retrieved. This system depends on the function of medial temporal areas, particularly an organ called the hippocampus, now the object of intense study. Another system, commonly known as motor learning, is subconscious and depends on other brain systems. This explains why people can jump on a bike after years away from one and take the thing for a ride, or why they can pick up a guitar that they have not played in years and still remember how to strum it.
Not too long ago, I wrote here about the role of "memory" (sanskara) in defining the ego-self. Following Red Pine, I said that memory provides us the templates that perception applies to sensation. It embraces all of the ways we have dealt with what we have experienced in the past and that are available to us as ways to deal with what we find in the present. It includes habitual behavior patterns such as intelligence, belief, shame, confidence, indolence, pride, anger, envy, sloth, repentance, doubt – anything that might provide us with a prefabricated set of guidelines from the past with which to perceive and deal with the world, both inside and out, as we experience it in the present.
H.M.'s condition tells us something about sanskara as well as physiology, for despite his condition, he was nonetheless a self-conscious presence, as open to a good joke and as sensitive as anyone in the room. Once, a researcher visiting him turned to his doctor while he was standing right there in front of them and remarked on how interesting a case this patient was. Since he was in clear ear-shot of this remark, he blushed and mumbled how he didn’t think he was all that interesting and moved away, a self-conscious response to an embarrassing situation.
Sanskara had provided H.M. with a way to react to the situation, even though his mind was free of declarative memories. Despite his condition, he could recount childhood memories of hiking in the mountains, road trips with his parents, target shooting in the woods near his house. Gist memories, as they're called. He had these memories, but he couldn’t place them in exact time, he couldn’t put them together into a personal narrative.
So sanskara is not to be found in declarative memory, in the hippocampus. And gist memories seem to me to be traces of declarative memory, mere echoes or ghosts in the machinery of the mind, and not the repository of the templates of sanskara.
It's likely, then, that sanskara, is more closely related to subconscious motor learning than to declarative memory, which in itself has interesting implications in the mind/body duality problem. Just as we rely on motor learning to tell us how to pitch a baseball or refrain from putting our hand on hot objects, so too it provides us with emotional guidelines on how to react to the situations we encounter.
In Buddhism, it's taught that the ego-self is merely the sum of the aggregates of form, sensation, perception, sanskara and consciousness. When any one of these is absent, a sentient being no longer considers itself to be a self. As H.M. was self aware despite his condition, sanskara must have been present. Were it to have disappeared along with his declarative memory, he would have been like a vegetable - not knowing how to perceive any sensation, he would not have known how to react to any situation and would have just stared blankly into space at all times. He would have seemed comatose, but for no identifiable reason, and tragically would have been conscious of this situation and aware of his inability to respond. And since he wouldn't even have known how to respond to his internal sensations, including his awareness of his own catatosis, the concept of an ego-self would not have arisen in his mind.
It is due to sanskara's ability to provide us with responses to perception that it is sometimes translated as "impulse" or "volition," although I think its meaning is broader than either of those two terms. It's ability to provide us with responses to internal perceptions of the mind has led it to be called "mental formations" and even "thought," although I also think there terms also miss the mark. And now, upon contemplating the late, unfortunate H.M., I now realize that sanskara is more specific than the broader term "memory."