Why We Forget and How to Remember Better, page 14
Forget That Memory
The converse is also true: If you tell someone that content is unimportant to remember, they won’t do very well at retaining the information, even if they didn’t realize its irrelevance when they first encountered it. For example, Robert Bjork at the University of California at Los Angeles showed participants lists of words and told them they would be tested on them later. But after one of the lists, participants were told that they were accidentally shown the wrong list, and those specific words wouldn’t be tested. In reality, the participants’ memories were tested for all of the words. The key result is that participants did worse at recalling the words from the list they were told they didn’t need to remember.2 It’s as if, upon finding out that the information is not relevant, you can wipe your mental slate clean.
This ability to keep unwanted details out of your memory structures can be quite important, because sometimes it’s not just that the information is irrelevant, but that the information is incorrect. If someone gives you erroneous information, it behooves you to wipe that detail from your memory structures and, if possible, to replace it with the correct content. Although none of us are perfect at doing this, when an error is identified soon after learning, these “intentional forgetting” mechanisms can reduce the likelihood that the error gets represented in your memory structure, minimizing your reliance on the faulty information for decision-making.3
These results emphasize that you can exert some control over the information that gets prioritized for building into your memory structures. Details can be removed from the construction when you realize they are unimportant or erroneous, and they can be added in high relief when their importance becomes apparent soon after learning.
Controlling What Details You Store Internally
Whether you realize it or not, you are constantly making choices that affect whether you store content internally in your brain or externally in the world. Do you attempt to memorize a shopping list or write it down with no expectation that you will remember the items without consulting the list? Do you try to learn the information you look up online or in a book, or only learn where to find it again the next time you need it?
You also may rely on the fact that other people can serve as your external memory aids.4 You might rely on your business partner to remember clients’ names, your spouse to keep track of where the recipe for a favorite dish is kept, and your child to recall the dates of their performances you plan to attend.
It can be quite helpful to “outsource” your memories in this way, and we’ll talk about memory aids that help you to do this in Chapter 22. For example, it may not be worth the effort to memorize a list of grocery items, and it often isn’t efficient for there to be high redundancy in the information that different members of a company—or a household—represent in memory. Indeed, higher rates of transactional memory—that tendency to rely on others’ memories to supplement your own—tend to be related to better performance in businesses.5 So, outsourcing memory can be a smart strategy in many circumstances. However, problems arise if you don’t think through the repercussions of this offloading: If your business partner departs, is critical knowledge forever lost? If an oft-visited website is down for maintenance, what impact does this have on your ability to complete your task?
Controlling Which Details You Access from Memory
So far in this chapter, we’ve focused on controlling what content goes into memory. The example we began the chapter with is instead an example of controlling the content we pull back out of our memory stores. It’s also taken from a real event: During one of the first lectures that Elizabeth gave as a newly-minted professor, she tripped over a power cable and nearly fell fully onto the floor before she caught herself. The next class, as soon as she approached the location, that memory returned. The power cable was no longer there, and so it was not a helpful memory to have in mind while trying to remain composed at the front of the room. When the same memory sprang to mind the next class as well, Elizabeth set out to do something about it. When something cued her to think of that stumble—she walked past the part of the room where she had tripped, or saw a cable lying in another part of the room—she immediately tried to put the memory out of her mind. If she felt glimmers of the memory returning, she did all she could to squelch them, slamming on the mental brakes so that the full details of the event did not return to mind. It took a few classes, but soon the memory didn’t spring to mind every time she walked around the classroom. Now, although Elizabeth regularly teaches in that room, she rarely thinks about that event.
These additional details about the event emphasize two important principles of how you can control what you access from memory. First, it’s an effortful process. Elizabeth had to work to put the memory out of mind. Without putting in that effort, the memory probably would have continued to return for quite some time, cued by features in the room or by associations in Elizabeth’s own mind. Second, it’s not the same as erasing the memory. Elizabeth didn’t give herself amnesia for the event; she can still recall the memory, but she reduced the likelihood that it would be one of the first memories to come to mind when she enters that room.
Controlling the Emotion in Memories
Sometimes, you want to recall the content from a prior event, but you don’t want to fully re-experience its emotions. It might be motivating for you to remember the time you didn’t study enough for a final exam and wound up with a poor grade—you might be able to use that memory to help you hunker down and study for an upcoming test rather than socializing with friends. But it won’t help you to be consumed with the negative emotions you experienced upon first receiving your grade.
Similar to how you control the details you access from memory, you can work to control the emotions within a memory. Sometimes, you can control the emotion elicited by a memory in parallel with your control of access to the memory content, suppressing access to both the content of a memory and its emotion.6 Other times, you may be able to strategically regulate your emotions during memory retrieval so as to, over time, specifically dull the emotional facets of a memory while preserving other details in high relief.
Putting Memory Control to Work
To best control what you remember and what you forget, try the following:
• Create priority cues. Think directly about why something is important (or unimportant) to remember. If you’re listening to a professor, think to yourself, “This is likely to be on the exam.” If you’re listening to a friend talk about an upcoming trip, think, “I want to remember this so I can ask her about it later.”
• Be deliberate about outsourcing memory. In this digital age, it’s especially easy to rely on external memory aids, often without realizing you’re doing it, such as how passwords auto-complete, social media sends birthday reminders, and phone numbers are stored in your phone. Give thought to what information you choose to store externally versus internally, so you can make sure the information you store in your brain is the information most useful to keep there!
• Push it out of mind. If you have an experience like Elizabeth, finding that an unwanted memory is coming to mind, research from Michael Anderson and colleagues has shown that an effective strategy is to slam on your mental brakes, clearing your mind of the memory and forcing it from your consciousness.7 It’s important that you don’t just distract yourself. Instead, work to actively snuff out the memory, just as you’d use a snuffer to extinguish a flame.
12
Are you sure that’s not a false memory?
You are gathered around the dinner table with extended family, reminiscing about a prior Thanksgiving meal. The turkey wasn’t ready to eat until at least 8 p.m. Everyone was so hungry! It was past your daughter’s bedtime by the time the food was on the table, and she nearly fell asleep in her mashed potatoes. Everyone is laughing at the memory. But then your spouse gently interjects: Wasn’t that dinner before our daughter was born? He remembers cousin Suzy being at that dinner but, in recent years, she’s been spending Thanksgiving with her in-laws. You definitely remember your daughter being exhausted at that meal. But maybe Suzy was there . . . in which case it must have been before your daughter was born.
You’ve probably had a few moments like this one, when you transition from feeling confident in your memory to questioning some parts of it—maybe eventually realizing that an event could not have happened the way you remembered it.
Recall some of the reasons why memory errors occur, as we discussed in Chapters 7 through 9. You can’t attend to everything, and so some details never make it into your memory structure. And, without meaning to, each time you retrieve a memory, you may subtly—or even not so subtly—change how you reconstruct its features, omitting some details and distorting others. Usually, those omissions or distortions are innocuous, but sometimes they can lead you to have a misleading impression of what happened. Even when you can definitively determine what happened—perhaps there was a social media post or diary entry about the event—you may never quite feel satisfied, because there is still an alternate version of the past floating around in your memory that feels real to you.
Confident, yet Wrong
Are memories usually correct if you are confident about them? Yes and no. In many circumstances, confidence is an imperfect yet reasonably good marker of memory accuracy; most research shows a positive association between the two.1 But there can be important disconnects between the two, especially when information has been retrieved on multiple occasions or retold multiple times. In one clever experiment, researchers from Victoria University of Wellington in New Zealand and University of Victoria in British Colombia showed participants actual photos from their childhood intermixed with a photograph that was altered to create the appearance that the participant had been in a hot air balloon as a child.2 The participants were interviewed three times over 1 to 2 weeks, and each time they were shown each photo and asked to remember everything they could about the event. As you might expect, no participant immediately reported a memory upon seeing the fake photograph; but by the end of the third interview, half of the participants reported at least some details of a hot air balloon ride. Moreover, when asked to rate their confidence in the false memory, they put themselves around the midpoint of the confidence scale.
Imagination Inflation
Why do false memories like this happen? A likely contributor is that when you try to remember an event, you often imagine what might have happened. If someone says you’ve eaten at a restaurant before (but you have no memory of it) you’re likely to think about when you might have gone there, who you could have eaten with, and what you may have ordered. Now you’ve created a mental image, and once this mental image has been created, it can be hard for you to figure out if it’s just an imagining or if it’s an actual memory. As we described in Chapter 10, the construction of mental imagery relies on many of the same processes required for action or perception. So, it’s no wonder that, after imagining how something might have occurred a couple of times, you may come to believe that it really happened that way.
Confidence-Boosting Feedback
Sometimes, you aren’t confident in the content you’ve retrieved from memory. You may guess an answer when called upon by a teacher, or when asked yet another “why” question by your grandchild. But if you receive feedback that you are probably right—the professor responds, “good answer,” or your grandchild says, “oh, right, my teacher said that”—you will suddenly become much more confident in your answer. What’s particularly interesting is that you don’t just become more confident now; you also will remember being more confident at the time when you first responded. You might not remember your response was a guess; your memory may quickly convince you that you confidently knew the answer all along.
This is one of the reasons why, in police and legal work, there has been a push toward recording eyewitnesses’ first identifications of a suspect. The confidence in that first moment of identification can be recorded and later considered by judge and jury. The confidence of that first identification is a reasonably good predictor of accuracy, and certainly a much better predictor than later estimates of confidence that may be affected by feedback or coaching. Importantly, confirming feedback can not only inflate confidence in an identification but also lead an eyewitness to believe they had a better view of the event or suspect than they actually had—influencing multiple factors that a judge and jury consider when trying to determine the reliability of eyewitness testimony.3
Distorting Sources and Blending Memories
It’s often the case that our false memories aren’t entirely false. They might have some elements of true memories blended together in a way that creates an erroneous impression of the past. In the example at the start of the chapter, perhaps there was a late-night Thanksgiving meal before your daughter was born and also a Thanksgiving dinner, years later, that overlapped with your daughter’s afternoon naptime such that she’d been nearly asleep at the table. Over time, the memories may have become merged, preserving some details from each. The memories of the hot air balloon ride may similarly have contained elements from real events—perhaps of being high above the ground on a ride at a fairground, or of seeing a brightly-colored balloon and imagining the thrill of being in the air. These snippets—pulled out of actual memory structures and merged into one another—can set the foundation for a false memory.
The Power of Misinformation
You already know from earlier chapters that our memory for an event can easily be altered as we reconstruct the event’s details at each retrieval. That alteration is very likely to occur when someone we trust suggests that an event unfolded in a particular way. When the suggestion is wrong, the phenomenon is referred to as the misinformation effect.4 In one famous experiment by Elizabeth Loftus and colleagues,5 participants saw a simulated car accident that included a car going through a stop sign. In later questioning about the accident, some participants were asked about the circumstances in which the car went through a yield sign. Many of those who received this misleading question came to remember that the original video had contained a yield sign rather than a stop sign. This same research team revealed that even subtle suggestions can influence memory. Participants who were asked how fast a car was going when it “bumped” into another car remembered lower speeds than those asked how fast it was going when it “crashed.” So, perhaps cousin Suzy wasn’t at that Thanksgiving dinner—but the confident assertion that she was there could lead to her incorporation into your memory.
Perhaps counterintuitively, you can be a powerful source of your own misinformation. One example is if you lie. Individuals who lie, saying that erroneous details occurred during an event, can come to believe that those details really happened. Similarly, individuals who speak about an event and then later deny that they spoke about it can forget that they actually discussed the event’s details.6 But even if you aren’t attempting to deceive anyone, the way you reflect on past events—perhaps imagining some alternate versions (“what if . . .”)—also has the potential to introduce misinformation.
So Many Ways for Memory to Become Distorted
In case you—or someone you’re talking with about this book—need further convincing that false memories commonly arise, we’re going to ask you to participate in a brief experiment, adapted from “the DRM paradigm,” named for the three scientists who developed it: James Deese at Johns Hopkins University and Henry Roediger and Kathleen McDermott, both at Washington University in St. Louis.7 Read the set of words after the bullet and, in a little while, we’ll ask you to recall the ones that you remember:
• Table, sit, legs, seat, couch, desk, recliner, sofa, cushion, stool, bed, rest, dream, awake, pillow, snore, slumber, candy, sour, bitter, sugar, cake, eat, tooth, pie
You have a few advantages going into this task: You’re reading a book that has already given you some tips on how to remember information, and you know that you’re about to be quizzed on your memory. Even so, we anticipate that you may have a false memory. If not, you can try this experiment on a few friends; we anticipate that a least a few of them will.
Now, time for that memory test: Without looking back, what were those words on the list we presented earlier? There were a total of 25 words; take a minute or two to recall as many as you can.
If you’re like most people, you’ll do well remembering words toward the start of the list: table, sit, legs. This is called the primacy effect in memory, and it can also be seen for more complex events from our lives: It’s much easier to remember your “firsts,” whether it’s your first kiss, first day of college, or first overseas flight, than it is to remember later repetitions of similar events. What about the other words on the list: Did you remember sofa? bed? dream? candy? sugar? What about chair? sleep? sweet? If you remembered any of those last three words, then you’ve just had a false memory! You can go back and check the list to confirm; none of those words were on it. We do these types of demonstrations for high school and college students, lawyers and judges, doctors and nurses, and it’s always the same: A large proportion of people generate these non-presented words. Many are quite confident they were on the list. If you were someone who hadn’t seen the original list of words and were just going by the show of hands in the room, you’d probably be fairly convinced that those words were on the list. In fact, more people recall those words than some of the actually-presented words!
