Forgetting, or at least the pathological kind, is one of the great fears of this senior generation. So worrisome that the half serious epithet “if that happens to me, just shoot me” can be heard with respect to dementia. Few are likely to ask for such an out for any other disease.
And this special fear may be a coat tail for neuroscientist Scott Small's book 'Forgetting:The Benefits of Not Remembering'. And while he deals with the diseases erasing memory, his primary lessons about memory are the more complicated aspects of how it works and how essential forgetting is to it. The author's specialty within neurology is memory, so you will be led through a synopsis of how that occurs and no matter how complicated it seems, be assured he is only touching the high points.
These two statements in his prologue, I think, among his most important messages.
“Only in the past decade or so has a new science begun to coalesce to explain why forgetting in balance with memory is the true and very natural cognitive power bestowed on us to live in an ever-fluctuating world, one that is also often frightening and painful.”
“ “Who would want to have a photographic memory with a mind that never forgets?” I hope that after reading this book, you will appreciate that the answer is 'nobody'.”
The book is a surprisingly concise 200 pages with little repetition. I would have liked some subheads to break up the text within the chapters.
Except for the first chapter, a long one, the book seems readily comprehensible for a lay readership. The first chapter deals with the mechanics of perception, to laying down memories, and to storing them. My understanding would be served by at least two readings of it.
He does provide a cursory review of neuroscience focussing on memory and its recent popularity in professional study. And this, in turn, likely owes something to the increasing concern surrounding dementia, specifically Alzheimer's disease. He deals with this toward the end of the book.
I found the earlier parts of the book more intellectually intriguing, but I can understand the popular appeal and commercial value of the tie in to dementia.
Until recently “forgetting” has been seen as a glitch in memory and at least a nuisance. There were glimmers in recent years that it might be more than that and science has discovered it is to the point that forgetting is essential. Recent science (last decade) has led to a significant shift in understanding the role of forgetting.
It is beneficial to cognitive and creative abilities, emotional well being and societal health. He deals at some length with the tie in to creativity.
Among the ideas he dismisses is “photographic memory” which he terms vanishingly rare. In search of superlatives, people latch on to this idea and attribute it to someone who merely has an advanced level of memory on the normal spectrum. He further dismisses it as a “fabrication, a superhero”.
Such a comprehensive complete memory would lead to chaos then likely gridlock and great anguish.
He is similarly dismissive of retrograde amnesia (complete loss of stored memories) as extremely rare, except on soap opera TV, where people forget complete segments of their recent life.
A balance between memory and forgetting allows a flexibility to accommodate a changing environment and ability to see the forest and not just the trees. Without this “flights of creative fantasy would be moored by memory”.
Small delves into autism and its relation to memory.
Rather than make the presentation entirely in the abstract, the author presents studies of three of his patients each representing a different issue of memory. Much of this is presented with Small answering the questions of his patients so the issue is contextualized for the reader.
One particularly significant value of forgetting is in the case of fear and anger, both residing in the amygdala of the brain. Here, for mental health and even survival, being able to blunt the vividness of memories is crucial to getting on with life. This is most dramatically exemplified in Post Traumatic Stress Disorder (PTSD). Small calls it a “toxic gain of emotional memory...too much memory.”
The author, as an academic, makes little judgement of 'superior and inferior', in his quest for answers and ideas.
This is my first experience with a book about the brain that provides so much brain 'geography'. I admit I hadn't thought much about where in the brain certain things happen. Dealing with the idea, the electrical processes happen in fixed places and through patterns takes away a sense of magic. And in its place is a huge amount of complexity. This book details it with respect to the issues the author focuses on.
Small does not deal with the issue of the two hemisphere's of the brain or how they fit into the brain's activity.
Memories, he says are flexible, shifting, fragmented and not formed instantly.
The first patient he introduces is Karl, a criminal defence lawyer in his 70s, who is experiencing a decline in his once vaunted memory, especially recent memories, and worries that he may be developing Alzheimer's. That proved not to be the case, but there was decline in his earlier spectacular functioning hippocampi.
Small allows a comparison between the human brain and a computer where both have the same three issues on how to handle vast amounts of information, 1.where to store the memories, 2.how to save the memories in a dedicated storage site and 3.how to open and retrieve the memories on demand.
There are three main anatomical “actors” in the brain. Many of our most cherished memories, he says, are stored in the back in what he simplifies as the “posterior area”. Before going there the memories are saved in the hippocampus located deep in the centre of the brain. Memories are opened and retrieved in the prefrontal cortex at the front of the brain. The unit of storage is cell or neuron.
These neurons have branches extending from them to further pointy structures called 'dendrites'. Like spines, these grow from stimulation and meet and connect with those of other cells communicating information. The size of these spines determines the 'loudness' of the connection.
This growth absorbs a lot of energy, hence the great energy demands of the brain. A large number of cells (millions) may be participating in storing a relatively small perception then communicate to create a larger whole in an area, Small refers to as a “hub”.
The brain essentially breaks down the perception and then gradually reconstructs it in progressively larger hubs in different areas of the cortex. The large central hubs are located in the “posterior area”. This process can be interrupted by a stroke or tumour.
The hippocampus stabilizes neurons in hubs giving the conscious memories more durability. Small describes the hippocampus like a “memory teacher” controlling young undisciplined students. Saving in the hippocampus may “take weeks” and varies with its efficiency.
Once the memories are sent off to storage, the hippocampus prunes back the spines. The new memories have already been made. The prefrontal cortex is at least partially involved in retrieving these memories when needed, like the operating system in the computer (it is the “memory librarian”) finding the needed memories in storage.
Inability to find a desired word sought, only to have it 'pop into one's head' with increased frequency, suggest an issue in the prefrontal cortex, says Small.
He suggests other examples of brain function. Remembering where you car is parked in the lot or your keys in the morning are hippocampi work.
Small says tests are coming to determine the difference between age related decline and Alzheimer's.
Like most other experts, he sees little help from drugs and the only validated way to improve brain function is through physical exercise, with maybe assistance from diet. “Cognitive exercises” continue to be investigated.
Small describes ' remembering' and 'forgetting' each having their own toolboxes with deliberate and necessary duties to perform, building and shrinking dendritic spines.
He says that perfect memory may suit recall of baseball stats or reciting poetry or living in an unchanging environment, but not for the real world.
He delves into the early work on autism. He paraphrases one of the early pioneers Leo Kanner who said that autistic children desire to live in a static world. And they don't tolerate change well. They do not like deviation from the details of their memory. They may be overly fixated on the parts and not easily able to synthesize these into an integrated whole. They often have 'remarkable' memories (savantism), but not able to synthesize from them.
To cognitively generalize, people have to have 'normal forgetting'. Research has suggested that autism is correlated with certain genes associated with forgetting and “anxiety-provoking cognitive chaos”.
People, without autism, may experience this chaos in a situation with too much novelty and unfamiliar things happening.....”endless shock and awe”.
The author regularly refers to a short story 'Funes, the Memorious' where the hero is unable to forget and how that restricts his life.
“Continuous alterations to existing memories are vital for us to adapt to our rapidly shape-shifting worlds.”
“Rote memory depends on how well cortical hubs function and, unlike associative memory, may depend very little on the hippocampus.”
Autism is characterized by “repetitive and restrictive behaviours” and behavioural inflexibility. Limitations in pattern recognition in autism also present problems in social interaction and seeing cues.
Forgetting may be more important in computers as well where facial recognition is the goal. It seems that more memory is not as important as more forgetting in the algorithm to create “computational flexibility”. Have to be able to see the forest and not just the trees.
“Autism has shown us how challenging life can become if the balance between memory and forgetting is thrown off-kilter by reduced forgetting,” says Small.
Emotional components of memory are closely linked to the amygdala and the subcortical hub. The memories of anger and fear, leading to high anxiety, can be among the most destructive to an individual.
“Normal emotional forgetting liberates us from.....traits that can be categorized as the amygdala's deadly sins: spite, vindictiveness, malice, vengefulness and righteous indignation.” It is the central command for danger management. It readily stores negative memories and the more that are stored the more active it becomes.
“Letting go of seething resentments is required for forgiveness.....the noblest example of the benefits of a forgetful mind.”We should forget enough for our sanity and well being.”
Small says that memories are continuously sculpted and eventually creative minds abstract, contort and even distort the past.
He takes a fascinating divergence into two other species to compare with humans. They are our closest relatives, the chimpanzee and the bonobo. In temperament we seem somewhere between the comparatively angry and violent chimp and the easygoing bonobo.
He discusses differences that to a considerable extent come from childhood experiences along with genes. It is the amygdala, the seat of anger and fear, that see the most significant differences in the brains of chimps and bonobos. He describes chimp society as “ruthless and unforgiving”.
The key adaptive trait of chimps, he says, is 'fear' and for bonobos 'fearlessness'. Chimps competing with gorillas live in a much rougher neighbourhood than bonobos.
And a tip to alcohol. Feelings toward others improves with the first drink, less so with subsequent ones. The drug slows activity in the amygdala. Fear can readily transition to aggression, a protective response that has evolved. But a braking on that fear is also an adaptive response as the grounds for fear fade and to a degree are forgotten.
An explosive event can 'damage' our brains upsetting the balance between emotional memory and emotional forgetting, effectively disordering personalities.
He points out that Alzheimer's begins in the hippocampus and migrates to other regions. Small was asked for his opinion on the influence of the disease on the work of a renowned artist. The artistic establishment wanted to determine if work in the artist's later years, with Alzheimer's, could be seen as a normal trajectory of his creativity, or something else. The decision would decide whether this later work would be shown with his earlier. The conclusion was that his later work was still representative of him as an evolving artist.
While progression of the disease would render many people unable to continue their profession this is not the case with artists.
“The recurrent theme that epitomizes the creative process is not generating something brand new out of the blue. Rather a creative spark occurs when unexpected associations among existing elements are suddenly forged---a sort of cognitive alchemy.”
“Creativity requires preexisting associations...requires memory..but they must remain loose and playful. The artist's testimonials teach us that creative abilities are forged by immersion in various elements and the establishment of associations between them, but only when the links are relaxed.”
“All visual artists immerse themselves in visions, poets in words, scientists in facts and ideas. But what sets the great ones apart is that their associations are not set in stone.”
This all ties in with the contention that alcohol, in small amounts, relaxes the brain and makes it more playful and hence fertile for innovation. There also seems a correlation with good sleep, dreams and sleep induced forgetting. “Forgetting unmoors us from memories that weigh our minds down and prevents flights of fancy and creativity.”
An eventful day, followed by good sleep leading to well trimmed dendrites lightens and refreshes the mind to record the day ahead.
He ventures into an explanation of the need for sleep, which is still largely unknown. However, the latest thinking is that memories, or many of the dendrites responsible for them, are pruned back and a synopsis of events retained. The brain could not accommodate the dendrite growth to save the complete memories of all the stimuli encountered nor could the brain function with all of this memory. So forgetting may be one of the big needs for sleep.
And shrinkage of spines “takes hours of the delicate molecular machinery that governs active forgetting.”
The hippocampus has a primary role in forming long term memories, which are stored in the posterior cortical area and the prefrontal cortex helps retrieve memories from cortical storage sites.
This review sets the stage for a patient, Dr. X, with an unusual memory issue. He is a renowned physician with exceptional diagnostic abilities. From childhood, he thought he had a poor memory, an unusual weakness in a physician. At the same time, he had a particularly high I.Q. and a strong “executive function” (prefrontal cortex).
The hippocampus memory system starts operating around the age of three, hence few memories before then. The prefrontal cortex becomes fully functional in late teens or 20s. Children can memorize as well as adults, but cannot reason or decide as well and have difficulty controlling impulses.
It was determined that the physician had below average hippocampal activity and above average prefrontal.
Aware of his memory issue, the physician was somewhat cautious especially in making diagnoses. This is not good brain activity for emergency medicine or airline pilots, but for his role it worked well. But his concern led to an “intellectual humility” and not so quick or certain to judgement. Effectively his diagnoses in complex, challenging cases was better than those with better memories, but less likely to change their minds.
Small suggests the he compensated for a weaker hippocampus with a stronger prefrontal cortex. Not the first and fastest, but the most accurate.
The author briefly explains the decision making theories pioneered by Daniel Kahneman and Amos Tversky. They described 'fast' and 'slow' thinking. Some occasions demand fast thinking. It (cognitive heuristics) are the easiest and first to be relied on, but also more prone to error.
We resist slow thinking because it takes more time and effort, but less likely to be wrong.
Kahneman says “nothing gives him more pleasure than changing his mind when warranted.”
One can tell that the author holds the octogenarian Nobel winner in reverence.
Small echoes the idea that the current crop of Alzheimer's drugs, the first generation “have modest benefits at best”. Although discovered in 1906, there was little mention in medical textbooks until the late 70s. More people living longer seemed the motivation for more investigation into it. It is now one of the most common and dreaded diseases with great sensitivity and fear accompanying the normal hippocampi decline issues. Modern medical imaging now aids in diagnosis.
He explains that Alzheimer's risk genes in themselves don't mean the disease will occur, but the likelihood increases with obesity, heart disease and diabetes. Early onset diabetes, caused by one gene is rare, possibly one per cent of cases.
Smart says the loss of memory in the early stages in information processing areas is not harmful to enjoying life, particularly when career performance is not an issue.. Problems arise when the people are not protected from the negative decisions or consequences. Suffering is often worse for the friends and family than the sufferer. Forgetting names is one of the most frightening for those close.
Such things as remembering a name is in a network of the hippocampi, amygdalae and cortex working together in connecting the audible name with the visual face and personal details.
Small refers to nostalgia as harmless wistfulness and often positive, until it becomes obsessive with no balancing forgetting (hypernesia).
And with further anatomical explanation “defective proteins are the primary drivers of disease, and many therapies end up trying to correct protein defects in one way or another.” And the brain has subtly different proteins in different areas.