Why We Forget and How to Remember Better, page 8
Disorders of Semantic Memory
Now that you know where semantic memory is located in the brain, it should not surprise you to learn that disorders that damage the outer part of the temporal lobes impair semantic memory. Alzheimer’s disease is the most common disorder that disrupts semantic memory. This explains why individuals with Alzheimer’s disease—in addition to having difficulty remembering recent events with their episodic memory—also have word-finding difficulties. In fact, it is such a common problem in this disease that family members often develop the habit of jumping in with the word their loved one is looking for.
There is also the disorder that our professor had at the beginning of this chapter, the semantic variant of primary progressive aphasia. That’s a mouthful, but all it really means is that it’s slowly progressive, the primary disorder is with language (aphasia means “speechless” in Greek), and semantic memory is impaired. Like our professor, these individuals have lost many of the words for everyday people, animals, and things—as if they forgot their primary language. There is also a related disorder called semantic dementia. The difference is that although those with the former disorder may have lost the words Kamala Harris, parrot, and cup, if they are shown pictures, they still know that she was the first woman to be vice president, it’s a bird that can talk, and it’s used for drinking. Those with semantic dementia may not know who Kamala Harris is or what parrots or cups are, as if they grew up in a culture without these people, animals, and things. We’ll briefly discuss these disorders in Chapter 13.
Because a lot of other brain disorders can affect the temporal lobes, there are a lot of other causes of semantic memory impairments, including tumors, strokes, and infections such as encephalitis. We’ll discuss these disorders in Chapter 14.
Want to Improve Your Memory for Facts?
As mentioned in the beginning of this chapter, you use your episodic memory to learn new facts. In Part 2 you will learn more about what helps—and what hinders—long-term episodic and semantic memories, including memories for facts. And Parts 4 and 5 are entirely devoted to what you can do to remember everything better, from people’s names to dates, facts, and formulas. In other words, read on! (And feel free to jump directly to those sections if you wish.)
Below are a few key suggestions that will help you learn new semantic information:
• Form strong episodic memories of the facts you wish to learn.
◦ Because semantic memory is based on the information acquired through episodic memory, it is critical to begin with a strong episodic memory.
• Get a good night’s sleep.
◦ Whether you are trying to remember to remember vocabulary words, history dates, mathematical formulas, or a new programming language, you’ll remember information better if you put down your book and allow your brain to consolidate your memories during sleep.
• Study facts in different contexts.
◦ Part of what makes semantic memory powerful is that it is knowledge you can pull out and use in a variety of different situations. In order to make your knowledge flexible, study facts in different ways. Cue yourself with a word to recall its definition, and also cue yourself with the definition to recall the word.
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Collective memory
What we remember together
You’re walking with your spouse down a country lane when you come to an old mill. “I just love these old mills with their waterwheels,” you say. “It reminds me of the photo we have of the two of us in front of the mill in Pennsylvania when we were planning our wedding.”
“Yes,” your spouse replies, “except that mill was in New Jersey, not Pennsylvania, and that photo was from the first time you met my parents, not when we were engaged.”
“That’s right,” you say, the memory coming back to you now, as you recall how you went to the mill after meeting your future in-laws, set up your tripod, and took the picture. Returning home, you pull the old picture out and smile. Sure enough, you can see the symbol for the New Jersey Register of Historic Places in front of the mill. But what’s that? You look closely—and can clearly see the hand proudly showing the new engagement ring.
It’s natural to think about your memories as belonging to you. After all, they are created by your brain, reflect your past, and help you to make decisions about your future. But before we close Part 1, we want to challenge you to think about “your” memories a little differently, to reflect that some of their utility comes from the way they are shared with others, and to consider that they are shaped by those with whom you reminisce.
The Power of Shared Memories
The prior chapter discussed semantic memory, the set of factual knowledge you have accumulated over your lifetime. Much of it is hard-earned knowledge—acquired because you took the time to read, study, and listen—and, in that sense, it is most definitely yours. But now consider that much of the power of this knowledge comes from the fact that it overlaps with the content in others’ memory stores. If you were the only one to know the meaning of “fork” or “remote control,” the knowledge would be of little use to you. Even in domains of expertise—where there is utility in holding knowledge that not everyone has—there must be some foundational shared knowledge that allows you to understand the problem at hand and to effectively apply your expertise.
Shared Scaffolding
Over your lifetime, you not only acquire facts about the world, but also develop ways to organize that knowledge. Picture a classroom. You may have quickly brought to mind a rectangular-shaped room, with a teacher standing at the front and with students sitting quietly at rows of desks facing the front. This image forms effortlessly, because you have an organized scaffolding or schema for a typical classroom. Schemas can include information not only about spatial layout but also about the progression of events. Imagine arriving for your first appointment at a new doctor’s office. Even though you’ve not been there before, your schema likely includes details such as first checking in with a receptionist, filling out forms on a clipboard, and then taking a seat in a waiting room until you are called. Depending on your experiences, your schema may include other details, like the tendency for appointments to run behind schedule or the presence of magazines in the waiting area.
These types of schemas are incredibly helpful. When Elizabeth walks into a new classroom on the first day of the semester, she doesn’t need to expend any mental effort to figure out where she should stand. And you don’t risk waiting in a doctor’s office for hours because you didn’t know to tell them you’d arrived.
When There Is No Scaffolding
With the COVID-19 pandemic, we all experienced the discomfort that happens when we are placed in circumstances for which our schemas are incorrect or nonexistent. You might have arrived for a doctor’s visit to find that the waiting area was closed. When Elizabeth walked into a classroom that had furniture rearranged to allow for physical distancing, it took her a moment to figure out where she should stand. She also had to work to remember the sanitizing steps that had never previously been part of her getting-ready-for-class schema.
Pushing yourself into situations in which you have no schemas can be an exciting and positive experience, such as when you travel to a part of the world you haven’t visited before or take a class on a topic that is entirely new to you. But with the exhilaration comes added mental effort, because you are unable to take as many shortcuts in figuring out what will happen next. Things that might be obvious when you’re in familiar territory—how much you should tip after a meal, whether you should drink the water, or how you should prepare for an exam—may suddenly require substantial thought in these novel contexts. Keep in mind that if the first days of a trip feel exhausting or if you doubt your ability to succeed as you begin a new course of study, part of your effort is expended building up the scaffolding that will make the next phase of the trip or the preparation for the next exam easier.
Shared Scaffoldings Shape Individual Memories
Schemas don’t just make life easier in the moment. They also shape what content you’ll later be able to remember about those moments. It’s fairly easy to remember information consistent with your schema (there were magazines in the doctor’s office). It can be particularly hard to remember information that is entirely missing from your schema (did you pay when checking in, or at the end of your appointment?). And when information is inconsistent with your schema (the doctor saw you on time), sometimes the surprise can make the detail memorable, but other times, you’ll default to the knowledge held in your schema and have an erroneous memory (you may later think the doctor was behind schedule, as usual).
When individuals have similar schemas, similar content will get into their memories and similar content will be left out. So, if you are a superhero fan and you watch a superhero movie in a theater with dozens of other fans, there will be much overlap in what you all remember from the movie. But there can also be informative points of departure: If the movie includes a car chase through the streets of Tokyo, moviegoers who have spent substantial time there may remember the scenes filmed on location in Tokyo much better than those filmed in the studio. Moviegoers who are car aficionados may best remember the moments when a car completed a turn with the tight turning radius it is known for, or when the camera angle highlighted the aerodynamic features of a car’s design. If you have no schema for either Tokyo or sports cars, you may remember little about the car chase; you might even omit it from your recall of the movie altogether.
When people remember events together, they also develop similar memory structures for those past events.1 This means that members of a community who reminisce about events together will build similar schemas, which in turn can lead them to create more similar individual memories for later events. This also means that individuals who are not part of those reminiscences can develop different schemas. Sometimes, these differences can be largely irrelevant, but other times, they can radically color how individuals remember and interpret events.
Collective Memory and Shared Narratives
Groups of individuals often share more than just the scaffolding for memories. You can have whole narratives and representations of past events that you share with small groups of individuals or large communities of people, from your family members or roommates to your company, school, congregation, political party, or country. These memories might be representations of events you personally remember, or they might be events that took place before you were born but have been described to you with enough repetition that they have become part of your store of knowledge. These shared event representations are termed collective memory, a phrase that aptly captures both their extension to all members of a group and their reliance on gathering together information to preserve it over time.
Wars and Family Feuds
Collective memory at the level of large communities often refers to representations of historical events, such as the narratives regarding a war or the ability to recount a country’s leaders. In a series of studies, the psychologists Henry Roediger and Andrew DeSoto have shown that, although these narratives are often shared within a country or generation, there are important divergences across geographical or generational boundaries. For instance, most individuals have a narrative for World War II, even if they were not alive at the time. If you’re an American, part of the shared narrative is that you probably consider the attack on Pearl Harbor and D-Day as critical events. But that shared narrative can diverge and splinter in various ways. Many older Americans viewed the bombings of Japan positively (focusing on how they ended the war and spared lives), while most younger Americans viewed them quite negatively (focusing on the death and destruction they caused). Russians remember events not known by many Americans, such as the Battle of Stalingrad, and they refer to the war as the Great Patriotic War rather than World War II. Like individual people, whole countries tend to overestimate their contributions to international efforts, often referred to as “national narcissism.” Citizens—whether from Allied or Axis countries—tend to remember their country’s contribution to the war as greater than it actually was.2
These collective memories are built up through many avenues: books read, lessons learned in school, media coverage of events. But it doesn’t require such formal recordkeeping for collective memories to emerge. Something similar often plays out in families through conversation. Your parents and grandparents may have a narrative for the rift that happened between your great-grandmother’s side of the family and your great-aunt’s side of the family. This narrative may influence how you and your siblings think about family members in your great-aunt’s lineage and, whether you are consciously aware of it or not, may influence how you interpret and remember their behaviors in the present day. (She wasn’t really sick, she just didn’t want to attend the family gathering.) Of course, your great-aunt’s side of the family has their own narrative for the rift, one that probably differs in some important ways from the narrative passed down to you—and their narrative probably influences how they interpret and remember your actions. So, without meaning to, we may “take sides” because of the narrative we’ve internalized even though we didn’t directly witness an event. Whether in a family, friendship, or romantic relationship, sometimes an important first step toward moving beyond a conflict is recognizing when there are different narrative beliefs that are held about what happened in the past. Until those are acknowledged, and effort is put into counteracting how those narratives may influence the way that current behaviors are interpreted and remembered, it can be nearly impossible not to bring the baggage of past conflicts into the present.
Working Together to Remember
You may focus on moments when you are alone as you use your memories—such as when taking an exam or remembering a shopping list—but these situations are usually the exception rather than the rule. Your memories are commonly created and retrieved while you’re surrounded by others. Perhaps you are part of a study group, working together to learn vocabulary that will be tested on an upcoming exam. Or you’re part of a clinical care team, recounting together the events that precipitated the patient’s transfer to your unit. Perhaps you are reminiscing over dinner, enjoying the positive emotions that spring forth as you recount your honeymoon with your spouse. Or maybe you’re sharing a memory online, posting photos and making comments with your friends about your weekend spent together. In each case, memory becomes a collaborative venture—and that affects the way that memory works in some interesting ways.
Collaborative Memory
From classrooms to boardrooms, we often work with others to learn information. The support we receive in these collaborative environments can be essential to our ability to learn. Collaborative learning can provide a powerful way to increase critical thinking skills and can help you move past sticking points in your ability to learn information.3 So, whether you’re a student struggling to make sense of the material presented in class or part of a clinical care team trying to understand a patient’s symptoms, it will help you to collaborate with others.
If your goal is not to understand material but only to improve how much and how well you can commit something to memory, collaborating with others will not always help you achieve that goal. Collaborating with others does not always bring about memory benefits and, in fact, there can be some important downsides.4 While you collaborate with others, you will encode and store some of these details into your own memory, and the group’s efforts may help you stay more motivated, and in these ways, you can benefit from the collaboration. But there also can be downsides. Perhaps counterintuitively, collaboration can make it harder for you to memorize information or to retrieve previously learned details from memory than if you worked on your own. It also can be hard to distinguish the memory of the group from your individual memory. You might leave a study group feeling great about how many historical facts you know, only to realize (as you begin the exam) that some of that content was only represented in others’ brains—and not in yours. Another problem is that if someone in the group is wrong, the errors can also be transmitted to others in the group. So, if you’re a student who needs to memorize vocabulary, or a consultant on a team trying to learn content for a presentation that you—and you alone—will be giving, be sure the pros outweigh the cons before making those memory tasks a collaborative effort.
Reminiscing
We often spend time with others to retrieve shared memories, not because we need to perfectly recreate a past event, but because of the positive emotions and feelings of social connectedness that result from bringing such events to mind. Memories can provide a powerful social glue, making you feel connected with people even if you haven’t seen them in some time. Reminiscing can boost your mood, not only because of this social connectedness but also because the memories themselves can be rewarding. Megan Speer, Jamil Bhanji, and Mauricio Delgado at Rutgers University revealed that reflecting on a positive past event activates reward circuitry in the brain. In fact, the positive memories were so rewarding that, when they gave participants a choice between retrieving a positive memory or receiving a small financial reward, participants were willing to forgo money in order to reminisce about the positive moments from their past!5
