Putting the science in fiction - Dan Koboldt, Chuck Wendig 2018
Misconceptions about memory
The brain is wider than the sky
By Anne M. Lipton, M.D., Ph.D.
Memory is crucial to a sense of self, and memory loss can be devastating to a person in real life—or a character in a story. Thus, remembering and forgetting make for good plot points and have given rise to a number of writing tropes. Popular culture has thereby colored our perceptions about the nature of memory, and not always accurately. On the one hand, a person is unlikely to have total recall. On the other hand, someone is unlikely to forget his life completely. Reality lies somewhere between these extremes. To help writers lend authenticity to their character and story arcs, this chapter addresses some common misconceptions about memory via neuroscientific principles and clinically based perspectives.
Myth #1: Memory = attention (or language or visuospatial skills or all of the above)
Memory refers to specific cognitive processes for the encoding (processing), storage, and recall (retrieval) of information. These functions are analogous to writing, filing, and later reading a message.
Neuroscientists refer to mental processing as cognition. Besides memory, the other main areas of cognition are attention/concentration, executive functioning, language, and visuospatial skills. Executive functions are higher-order thought processes such as insight, judgment, planning, and organization, mediated by the brain’s frontal lobes.
Sometimes people conflate memory with another cognitive domain—or all of them. For example, a person may have difficulty recognizing faces (prosopagnosia). This type of perceptual difficulty, or agnosia, may be misinterpreted as a problem with recalling names. “Memory” is also sometimes incorrectly applied as shorthand for all aspects of cognition. However, in writing and in real life, it’s best to be specific.
Memory may be divided into declarative (explicit) memory, which can be tested verbally, and non-declarative (implicit-procedural) memory, involving perception and motor skills, such as riding a bike or playing an instrument. Episodic memory (recall of events) and semantic memory (one’s “encyclopedia” of learned facts) are types of declarative memory.
Anatomically, different brain regions mediate different aspects of memory. Key among these are areas in the brain’s frontal lobes and temporal lobes. The hippocampus and its associated entorhinal cortex are essential structures for explicit memory. Named for its seahorse-shape, the hippocampus is part of the limbic system, which includes the amygdala, a structure underlying basic drives and emotions.
Myth #2: Memory is a static, stand-alone function
Memory doesn’t operate in isolation. It works in concert with sensory input to the brain and is intertwined with other cognitive domains.
Numerous examples of what I call “made-for-TV amnesia” abound in movies and books like Robert Ludlum’s The Bourne Identity (Richard Marek Publishers, 1980). Jason Bourne finds himself in a strange place or situation and can’t remember his name. He is otherwise healthy and alert, walking, talking, and in fighting shape. Somehow, he can recall the names of things like phones, boats, or passports (words that one usually learns well after one’s name). He can learn new information and also remembers how to drive, etc. Memory doesn’t work like this.
People often see memory as operating independently of these other cognitive processes, but the system is interdependent. Language and memory are so tied together in terms of how we humans communicate and remember that memory is often classified in terms of verbal and nonverbal recall.
Visual memory tends to be the nonverbal type of most clinical interest. But other types of nonverbal memory can be just as important, if not more so, in daily life—and writing. Marcel Proust’s madeleine in Remembrance of Things Past is a sweet example of gustatory (taste) memory:
“And suddenly the memory revealed itself. The taste was that of the little piece of madeleine which on Sunday mornings at Combray (because on those mornings I did not go out before mass), when I went to say good morning to her in her bedroom, my aunt Léonie used to give me, dipping it first in her own cup of tea …”
Memory also has temporal patterns. Most laypeople use the terms short-term and long-term memory, but neuroscientists generally refer to working memory and reference memory or immediate (short-term), recent (e.g., current events), and remote (long-term) recall.
If a head injury (or similar insult) is severe enough, one may have retrograde amnesia (memory loss for recent events), particularly if there is altered consciousness. But this would be most profound for events around the time of the trauma. Jason Bourne could have such amnesia, but this would be unlikely to extend only to longstanding aspects of his identity while sparing more recent information. It should be the other way around. Ribot’s law of retrograde amnesia refers to the common phenomenon in which more recent memories are forgotten to a greater degree than more remote ones.
Someone with a traumatic brain injury (TBI) may also experience anterograde amnesia (difficulty learning and remembering new information). Jason Bourne doesn’t seem to have a problem with “new learning,” which also makes his selectively impaired recall less credulous: The more severe a trauma that caused amnesia, the more likely that anterograde amnesia (problems with learning and remembering new information) will occur. There’s no singular or centralized memory center that can be obliterated to erase all of someone’s memories. However, destruction of the bilateral hippocampi (each hippocampus on either side of the brain) can produce severe anterograde amnesia. Both hippocampi may be damaged after trauma or during a hypoxic (oxygen-depleting) event such as cardiopulmonary arrest.
A person who has completely forgotten her identity and journeys to find it again makes for a great story, which is probably why this plot point is so popular, even if it is so improbable. But our oldest and most-often used memories (e.g., our names) are what we memory specialists sometimes like to call overlearned information or what laypeople sometimes call hardwired. To suddenly forget one’s name, other identifying traits, and all the major players in one’s life, while otherwise functioning normally, is not easily explained by a head injury or other neurological insult. Because of the interconnectedness of cognitive processes, sudden and severe memory loss is likely to be associated with other medical issues.
For example, TBI can cause concussions with forgetfulness, but usually in the context of accompanying problems such as inattentiveness, headaches, and dizziness.
Transient global amnesia is a condition often linked to an underlying medical condition, such as blood vessel (vascular) disease or migraines. “Global” overstates the case, as the amnesia is often not total. Symptoms usually resolve within twenty-four hours.
Drugs may cause amnesia but are unlikely to cause someone to forget his identity unless he becomes delirious (a delirium = an acute confusional state).
Forgetting one’s identity while functioning normally in all other realms doesn’t fit with the anatomy or temporal patterns of memory and suggests a possible psychogenic amnesia (memory loss related to mental illness or psychological issues). After extreme physical and/or psychological trauma, such as severe abuse or another situation someone wishes to escape, a person may enter a profound “dissociative fugue” state (e.g., the man who washes up on the beach and can’t recall his name but can play the piano and learn the names of new people he meets). Such patients typically exhibit significant mood and/or behavioral symptoms. Psychogenic amnesia is distinct from “malingering” (deliberately faking memory loss or other illness in order to escape criminal proceedings or for some other personal gain).
Even in the case of a dementia such as Alzheimer’s disease, where memory loss is prominent (albeit gradual), a person’s name is likely to be the last thing she forgets.
Myth #3: The perfect memory
Memory is rather imperfect. Which is not necessarily a bad thing, although it can be if one’s fate depends on the testimony of eyewitnesses, who are notoriously unreliable. The perfect memory is right up there with the perfect murder and the unsinkable ship. But writers can leverage an unreliable character or narrator to great advantage.
Memory has its limits. Memories often fade with time or become reworked. Events associated with profound emotion (e.g., the death of a parent, September 11) sear memories into our consciousness. Retrieving a memory using cues (recognition memory) is easier than spontaneous (or free) recall. Repetition can aid memory—or alter it. The human penchant for pattern recognition may likewise help or bias our memory. Roast, roast, roast, roast. What do you put in a toaster? (Hint: not toast). This is an example of anchoring bias or focalism, in which the first piece of information biases decision-making.
Certainly, some people have better memory abilities than others, memory can improve with practice, and certain techniques (referred to as mnemonics) can aid memory. However, anyone who remembered everything would have a difficult time making it through everyday life (beautifully illustrated in the classic short story “Funes the Memorious” by Jorge Luis Borges). Besides, flawed characters are much more interesting. So are flawed, repressed, or unshakable memories. Every Superman should have his kryptonite.