Sunday, June 19, 2005

The Persistence of Memory

I’ve always been fascinated by human learning and memory, and I’m constantly reminded that the science of the 21st century is sadly lacking in the fundamental nature of gray matter. It was only a century ago when Phrenology was popular and “scientists” would measure bumps on your skull to determine your personality.

Dr. Oliver Sacks, famous for his amazing books “Awakenings” (Where Robin Williams played Sacks) and “The Man who Mistook his Wife for a Hat” (HIGHLY recommended), expanded on the idea of brain function localization. Freud postulated that the human brain is like a small tape recorder and that all memories are stored, and what is lost is not the memory itself, but the ability to recall the memory.

In one section, Dr. Sacks probes the brain of a conscious woman and find that she not only recalls childhood memory with electronic stimulus, and almost relives the memory, recalling verbatim the jingle on the radio and the smell of bread baking in the kitchen over 40 years ago.

Gary Larsen took off on the brain probe idea in one of his most famous cartoons. I firmly believe that what is lost when we “forget” is not the memory itself, but the neural connection to the memory (except in cases of anesthesia and psychoactive drugs that limit the brains ability to store the original memory). Making this “memory blocking” assumption codifies many theories of personality and insanity, especially repression and subconscious motivators in human behavior.

But still, nobody has ever mapped the human brain; and scientisis are woefully lacking in understanding the machinations of the human psyche.

Today we have not really come that far from Phrenology, and neuroscientists barely understand synapse functions, and we cannot even duplicate the processing of a fly’s brain. We have artificial eyes that can read a newspaper heading from outer space, but we have yet to develop a computer that can “perceive” the world around them, taking-in billions of bytes of data every second from their superior artificial eyes, ears and smell sensors.

See, I believe that today’s lack of “real-time” Artificial Intelligence is a function of our ancient computers. In College I was fortunate enough to take several classes taught by Professor Richard Harris where he developed reliable equations to describe human processing (such as altruism and equity), and I was a lab assistant for Professor Emeritus Frank Logan author of “Reward and Punishment” and “Logan’s Laws of Learning”.

The equations are there; the only thing missing is the computing hardware and the daily terabytes of storage required to create a machine that perceives the world around them. A linear regression of the falling costs and improved capacity of computers indicates that a true learning machine will become feasible by about 2040. I won’t be around to see it, but I believe that computers will someday be able to replicate human cognition.

Have you ever wondered why a certain smell evokes vivid memories of the past? Researchers have yet to fully-understand the relationship between long-term memory and olfactory senses and why a smell from the distant past often evokes a “re-living” of an event, much like Dr. Sacks artificial recall experiments.

Personally, I suspect that the increased recall from olfactory stimuli is because we use our visual and auditory sensors more than tactile and olfactory memory (this includes “taste” memory, as taste is really a function of small). If I’m right, this might also explain the “Idiot Savant” phenomenon (e.g. Dustin Hoffman in the movie Rain Man) where un-used cerebral components pave-the-way for superhuman mathematical and counting skills. Also, here is a fascinating study of the McGurk Effect on memory and aging.

On aging and memory

As people age we see an almost predictable decline in mental processing. The first thing most people say able an elderly friend is “And they still have their wits about them” as-if senile dementia is expected.

Is mental decline inevitable? I’ve met people in their 90’s that are sharp-as-a-tack, and I’ve met others with severe dementia in their 40’s. People were not meant to live as long as they do today.

I hope that I live long enough to witness 50 million baby-boomers start to loose their faculties, and the inevitable barrage of TV commercials! I’m already amazed at the aging-boomer ads on television for Viagra, Cialis, and those diapers for boomers without bladder control.