Idiot Brain (9 page)

The brain regularly edits memories to make them more flattering, whatever the rationale for doing so, and these edits and tweaks can become self-sustaining. If we remember and/or describe an event in a way that slightly emphasizes our role in it (we caught the biggest fish on a fishing trip, rather than the third biggest), the existing memory is then effectively “updated” with this new modification (the modification is arguably a new event, but is strongly linked to the existing memory, so the brain has to reconcile this somehow). And this happens again the next time it's recalled. And the next, and so on. It's one of those things that happens without you knowing or realizing, and the brain is so complex that there are often several different explanations for the same phenomenon, all occurring simultaneously, all of which are equally valid.

The upside of this is, even if you don't quite understand what's been written about here, you'll probably remember that you did, so it all ends up the same regardless. Good work.

Where am I? . . . Who am I?

(When and how the memory system can go wrong)

In this chapter, we've covered some of the more impressive and outlandish properties of the brain's memory system, but all of these have assumed that the memory is working normally (for want of a better term). But what if things go wrong? What can happen to disrupt the brain's memory systems? We've seen that ego can distort your memory, but that it rarely if ever distorts so severely it actually creates new memories for things that didn't actually happen. This was an
attempt to reassure you. Now let's undo that by pointing out that I didn't say it
never
happens.

Take “false memories.” False memories can be very dangerous, especially if they're a false memory of something awful. There have been reports of arguably well-intentioned psychologists and psychiatrists trying to uncover repressed memories in patients who have seemingly ended up creating (supposedly by accident) the terrible memories they're trying to “uncover” in the first place. This is the psychological equivalent of poisoning the water supply.

The most worrying thing is that you don't need to be suffering from psychological issues to have false memories created in your head; it can happen to virtually anyone. It might seem a bit ridiculous that someone can implant false memories in our brains by just talking to us, but neurologically it's not that far-fetched. Language is seemingly fundamental to our way of thinking, and we base much of our world view on what other people think of and tell us (see
Chapter 7
).

Much of the research on false memories is focused on eyewitness testimonies.
³¹
In important legal cases, innocent lives could be altered forever by witnesses misremembering a single detail, or remembering something that didn't happen.

Eyewitness accounts are valuable in court but that's one of the worst places to obtain them. It's often a very tense and intimidating atmosphere and the people testifying are made fully aware of the seriousness of the situation, promising to “tell the truth, the whole truth and nothing but the truth, so help me God.” Promising a judge you won't lie and invoking the supreme creator of the universe to back you up? These aren't exactly casual circumstances, and probably will cause considerable stress and distraction.

People tend to be very suggestive to those they recognize as authority figures, and one persistent finding is that when people are being questioned about their memory, the nature of the question can have a major influence on what is remembered. The best-known name connected to this phenomenon is Professor Elizabeth Loftus, who has done extensive research into the subject.
³²
She herself regularly cites the worrying cases of individuals who have had extremely traumatic memories “implanted” (presumably accidentally) by questionable and untested therapeutic methods. A particularly famous case involves Nadine Cool, a woman who sought therapy for a traumatic experience in the 1980s and ended up with detailed memories of being part of a murderous satanic cult. This never happened though, and she ended up successfully suing the therapist for millions of dollars.
³³

Professor Loftus's research details several studies where people are shown videos of car accidents or similar occurrences and then asked questions about what was observed. It's been persistently found (in these and other studies) that the structure of the questions asked directly influences what an individual can remember.
³⁴
Such an occurrence is especially relevant for eyewitness testimonies.

In particular conditions, such as the individual being anxious and the question coming from someone with authority (say, the lawyer in a court room), specific wording can “create” a memory. For example, if the lawyer asks, “Was the defendant in the vicinity of the cheese store at the time of the great cheddar robbery?,” then the witness can answer yes or no, according to what he or she remembers. But if the lawyer asks, “Where in the cheese store was the defendant at the time of the great cheddar robbery?,” this question asserts that the
defendant
was definitely there
. The witness may not remember seeing the defendant, but the question, stated as a fact from a higher-status person, causes the brain to doubt its own records, and actually adjust them to conform to the new “facts” presented by this “reliable” source. The witness can end up saying something like, “I think he was standing next to the gorgonzola,” and mean it, even though he or she witnessed no such thing at the time. That something so fundamental to our society should have such a glaring vulnerability is disconcerting. I was once asked to testify in a court that all the witnesses for the prosecution could just be demonstrating false memories. I didn't do it, as I was worried I could inadvertently destroy the whole justice system.

We can see just how easy it is disrupt the memory
when it's functioning normally.
But what if something actually goes wrong with the brain mechanisms responsible for memory? There are a number of ways this can happen, none of which are particularly nice.

At the extreme end of the scale, there's serious brain damage, such as that caused by aggressive neurodegenerative conditions such as Alzheimer's disease. Alzheimer's (and other forms of dementia) is the result of widespread cell death throughout the brain, causing many symptoms, but the best known is unpredictable memory loss and disruption. The exact reason this occurs is uncertain, but one main theory at present is that it's caused by neurofibrillary tangles.
³⁵

Neurons are long, branching cells, and they have what are basically “skeletons” (called cytoskeletons) made of long protein chains. These long chains are called neurofilaments, and several neurofilaments combined into one “stronger”
structure, like the strands making up a rope, is a neurofibril. These provide structural support for the cell and help transport important substances along it. But, for some reason, in some people, these neurofibrils are no longer arranged in neat sequences, but end up tangled like a garden hose left unattended for five minutes. It could be a small but crucial mutation in a relevant gene causing the proteins to unfold in unpredictable ways; it could be some other currently unknown cellular process that gets more common as we age. Whatever the cause, this tangling seriously disrupts the workings of the neuron, choking off its essential processes, eventually causing it to die. And this happens throughout the brain, affecting almost all the areas involved in memory.

However, damage to memory doesn't have to be caused by a problem that occurs at the cellular level. Stroke, a disturbance in the blood supply to the brain, is also particularly bad for memory; the hippocampus, responsible for encoding and processing all our memories at all times, is an incredibly resource-intensive neurological region, requiring an uninterrupted supply of nutrients and metabolites. Fuel, essentially. A stroke can cut off this supply, even briefly, which is a bit like pulling the battery out of a laptop. Brevity is irrelevant; the damage is done. The memory system won't be working so well from now on. Although there is some hope, in that it has to be a powerful or particularly precise stroke (blood has many ways of getting to the brain) to cause serious memory problems.
³⁶

There's a difference between “unilateral” and “bilateral” strokes. In simple terms, the brain has two hemispheres, both of which have a hippocampus; a stroke that affects both is pretty devastating, but a stroke that affects just one hemisphere is more manageable. Much has been learned about
the memory system from subjects who have suffered varying memory deficits from strokes, or even weirdly precise injuries. One subject referenced in scientific studies on memory was an amnesia sufferer whose condition resulted from somehow getting a pool cue lodged right up his nose to the point where it physically damaged his brain.
³⁷
There's really no such thing as a “non-contact” sport.

There have even been cases where the memory-processing parts of the brain have been removed deliberately via surgery. This is how areas of the brain responsible for memory were recognized in the first place. In the days before brain scans and other flashy technology, there was Patient HM. Patient HM suffered severe temporal-lobe epilepsy, meaning the areas of his temporal lobe were causing debilitating fits so often that it was determined that they had to be removed. So they were, successfully, and the fits stopped. Unfortunately, so did his long-term memory. From then on, Patient HM could remember only the months leading up to surgery, and no more. He could remember things that happened to him less than a minute ago, but then he'd forget them. This is how it was established that the temporal lobe is where all the memory-formation workings are in the brain.
³⁸

Patients with hippocampal amnesia are still studied today, and the wider-reaching functions of the hippocampus are constantly being established. For example, a recent study from 2013 suggests that hippocampal damage impairs creative thinking ability.
³⁹
It makes sense; it must be harder to be creative if you can't retain and access interesting memories and combinations of stimuli.

Perhaps as interesting were the memory systems HM
didn't
lose. He clearly retained his short-term memory, but
information in short-term memory no longer had anywhere to go, so it faded away. He could learn new motor skills and abilities such as specific drawing techniques, but every time you tested him on a specific ability, he was convinced it was the first time he'd ever attempted it, despite being quite proficient at it. Clearly, this unconscious memory was processed elsewhere by different mechanisms that had been spared.
^†

Soap operas would lead you to believe that “retrograde amnesia” is the most common occurrence, meaning an inability to recall memories acquired before a trauma occurs. This is typically demonstrated by a character receiving a blow to the head (he fell and hit it in an unlikely plot device), regaining consciousness and asking, “Where am I? Who are you people?,” before slowly revealing he can't recall the past twenty years of his life.

This is far more unlikely than TV implies; the whole blow-to-the-head-and-lose-whole-life-story-and-identity thing is very rare. Individual memories are spread throughout the brain, so any injury that actually destroys them is likely to
destroy much of the whole brain as well.
⁴¹
If this happens, remembering your best friend's name probably isn't a priority. Similarly, the executive regions in the frontal lobe responsible for recollection are also pretty important for things such as decision-making, reasoning etc., so if they're disrupted then memory loss will be a relatively minor concern compared with the more pressing problems. People can and do demonstrate retrograde amnesia, but it is usually transient and memories eventually return. This doesn't make for good dramatic plots, but it's probably better for the individual.

If and when retrograde amnesia does occur, the nature of the disorder means it's very hard to study; it is difficult to assess and monitor the extent of someone's memory loss from their earlier life, because how would you know anything about this time? The patient could say, “I think I remember going to the zoo on a bus when I was eleven,” and it seems as though their memory is returning, but unless the doctor was actually on the bus with them at the time, how can anyone be sure? It could easily be a suggested or created memory. So in order to test and measure someone's memory loss from their earlier life, you'd need an accurate record of
their whole life
to measure any gaps or losses accurately, and having such a thing is rare.

The study of one type of retrograde amnesia resulting from a condition known as Wernicke-Korsakoff syndrome, typically the result of thiamine deficiency due to excessive alcoholism,
⁴²
benefited from an individual known as “Patient X,” a sufferer who had previously written an autobiography. This enabled doctors to study the extent of his memory loss more precisely as they had a reference to go from.
⁴³
We might see this happening more in the future, with more and more people charting their lives online via social media sites. But then, what people do online isn't
always an accurate reflection of their lives. You can imagine clinical psychologists accessing an amnesia patient's Facebook profile and assuming their memories should consist of mostly laughing at funny videos of cats.

The hippocampus is easily disrupted or damaged—by physical trauma, stroke, various types of dementia. Even Herpes Simplex, the virus responsible for cold sores, can occasionally turn very aggressive and attack the hippocampus.
⁴⁴
And, of course, as the hippocampus is essential for the formation of new memories, the more likely type of amnesia is anterograde: the inability to form new memories following a trauma. This is the sort of amnesia Patient HM suffered from (he died in 2008 at the age of seventy-eight). If you saw the film
Memento
, it's just like that. If you saw the film
Memento
but don't really remember it, that's not quite so helpful (but is ironic).