You probably haven’t given much thought to breathing today, and the reason is that from the moment you woke up, you’ve been doing it effortlessly and well. But the moment breathing fails, you are reminded of just how important it is. Memory is like that. Every time we see, think, notice, imagine, or wonder, we are drawing on our ability to use information stored in our brains, but it isn’t until this ability fails that we become acutely aware of just how much we should treasure it. Such memory errors—the “seven sins” of memory—cast similar illumination on how memory normally operates and how often it operates well (Schacter, 1999, 2001b). We’ll discuss each of the seven sins in detail below.

On March 6, 2007, I. Lewis “Scooter” Libby, former Chief of Staff to Vice President Dick Cheney, was convicted of perjury during an FBI investigation into whether members of the Bush administration had unlawfully disclosed the identity of a CIA agent to the media. According to Libby’s defense team, any misstatements he might have made in response to FBI questioning were the result of faulty memory, not an intention to deceive. How could Libby forget such important events? Research has shown that memories can and do degrade with time. The culprit here is transience, forgetting what occurs with the passage of time.

Transience occurs during the storage phase of memory after an experience has been encoded and before it is retrieved. This was first illustrated in the late 1870s by Hermann Ebbinghaus, a German philosopher who measured his own memory for lists of nonsense syllables at different delays after studying them (Ebbinghaus, 1885/1964). Ebbinghaus charted his recall of nonsense syllables over time, creating the forgetting curve shown in FIGURE 6.15. Ebbinghaus noted a rapid drop-off in retention during the first few tests, followed by a slower rate of forgetting on later tests—a general pattern confirmed by many subsequent memory researchers (Wixted & Ebbensen, 1991). So, for example, when English speakers were tested for memory of Spanish vocabulary acquired during high school or college courses 1 to 50 years earlier, there was a rapid drop-off in memory during the first 3 years after the students’ last class, followed by tiny losses in later years (Bahrick, 1984, 2000). In all these studies, memories didn’t fade at a constant rate as time passed; most forgetting happened soon after an event occurred, with increasingly less forgetting as more time passed.

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Another way that memories can be distorted is by interference from other memories. For example, if you carry out the same activities at work each day, by the time Friday rolls around, it may be difficult to remember what you did on Monday because later activities blend in with earlier ones. This is an example of retroactive interference, situations in which later learning impairs memory for information acquired earlier (Postman & Underwood, 1973). Proactive interference, in contrast, refers to situations in which earlier learning impairs memory for information acquired later. If you use the same parking lot each day at work or at school, you’ve probably gone out to find your car and then stood there confused by the memories of having parked it on previous days.

The great cellist Yo-Yo Ma put his treasured $2.5 million instrument in the trunk of a taxicab in Manhattan. He rode to his destination, paid the driver and left the cab, forgetting his cello. Minutes later, Ma realized what he had done and called the police. Fortunately, they tracked down the taxi and recovered the instrument (Finkelstein, 1999). But how had the celebrated cellist forgotten about something so important that had occurred only 10 minutes earlier? Transience is not a likely culprit. As soon as Mr. Ma realized what he’d done with his instrument, he recalled where he had put it. This information had not disappeared from his memory (which is why he was able to tell the police where the cello was). Instead, Yo-Yo Ma was a victim of absentmindedness, a lapse in attention that results in memory failure.

What makes people absentminded? One common cause is lack of attention. Attention plays a vital role in encoding information into long-term memory. Without proper attention, material is much less likely to be stored properly and recalled later. For example, in one study, participants listened to lists of 15 words for a later memory test (Craik et al., 1996). They were allowed to pay full attention to some of the lists, but while they heard other lists, they simultaneously performed another task that required them to press keys to indicate where an asterisk was appearing and disappearing. On a later test, participants recalled far fewer words from the list they had heard while their attention was divided.

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What happens in the brain when attention is divided? As you saw earlier, greater activity in the lower left frontal region during encoding is associated with better memory. But participants showed less activity in the lower left frontal lobe when their attention was divided (Shallice et al., 1994). Dividing attention, then, prevents the lower left frontal lobe from playing its normal role in semantic encoding, and the result is absentminded forgetting. Divided attention also leads to less hippocampal involvement in encoding (Kensinger, Clarke, & Corkin, 2003; Uncapher & Rugg, 2008). Given the importance of the hippocampus to episodic memory, this finding may help to explain why absentminded forgetting is sometimes so extreme, as when we forget where we put our keys or glasses only moments earlier.

Another common cause of absentmindedness is forgetting to carry out actions that we planned to do in the future. On any given day, you need to remember the times and places that your classes meet, you need to remember with whom and where you are having lunch, and so on; this is called prospective memory, remembering to do things in the future (Einstein & McDaniel, 1990, 2005).

Have you ever tried to recall the name of a famous movie actor or a book you’ve read—and felt that the answer was on the tip of your tongue, rolling around in your head somewhere but just out of reach at the moment? This tip-of-the-tongue experience is a classic example of blocking, a failure to retrieve information that is available in memory even though you are trying to produce it. The sought-after information has been encoded and stored, and a cue is available that would ordinarily trigger recall of it. The information has not faded from memory, and you aren’t forgetting to retrieve it. Rather, you are experiencing a full-blown retrieval failure, which makes this memory breakdown especially frustrating. Researchers have described the tip-of-the-tongue state, in particular, as “a mild torment, something like [being] on the brink of a sneeze” (Brown & McNeill, 1966, p. 326).

Blocking occurs especially often for the names of people and places (Cohen, 1990; Semenza, 2009; Valentine, Brennen, & Brédart, 1996). Why? Because their links to related concepts and knowledge are weaker than for common names. That somebody’s last name is Baker doesn’t tell us much about the person, but saying that he is a baker does. To illustrate this point, researchers showed people pictures of cartoon and comic strip characters, some with descriptive names that highlight key features of the character (e.g., Grumpy, Snow White, Scrooge) and others with arbitrary names (e.g., Aladdin, Mary Poppins, Pinocchio; Brédart & Valentine, 1998). Even though the two types of names were equally familiar to participants in the experiment, they blocked less often on the descriptive names than on the arbitrary names.

Although it’s frustrating when it occurs, blocking is a relatively infrequent event for most of us. However, it occurs more often as we grow older, and it is a very common complaint among people in their 60s and 70s (Burke et al., 1991; Schwartz, 2002). Even more striking, some individuals with brain damage live in a nearly perpetual tip-of-the-tongue state (Semenza, 2009). One such individual could recall the names of only 2 of 40 famous people when she saw their photographs, compared to 25 of 40 for healthy volunteers in the control group (Semenza & Zettin, 1989). Yet she could still recall correctly the occupations of 32 of these people—the same number that healthy people could recall. This case and similar ones have given researchers important clues about what parts of the brain are involved in retrieving proper names. Name blocking usually results from damage to parts of the left temporal lobe on the surface of the cortex, most often as a result of a stroke. In fact, studies that show strong activation of regions within the temporal lobe when people recall proper names support this idea (Damasio et al., 1996; Gorno-Tempini et al., 1998).

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Shortly after the 1995 bombing of the federal building in Oklahoma City, police set about searching for two suspects they called John Doe 1 and John Doe 2. John Doe 1 turned out to be Timothy McVeigh, who was quickly apprehended and later convicted of the crime and sentenced to death. John Doe 2, who had supposedly accompanied McVeigh when he rented a van two days before the bombing, was never found. In fact, John Doe 2 had never existed; he was a product of the memory of Tom Kessinger, a mechanic who was present when McVeigh rented the van. The day after, two other men had also rented a van in Kessinger’s presence. The first man, like McVeigh, was tall and fair. The second man was shorter and stockier, was dark-haired, wore a blue and white cap, and had a tattoo beneath his left sleeve—a match to the description of John Doe 2. Tom Kessinger had confused his recollections of men he had seen on separate days in the same place. He was a victim of memory misattribution, assigning a recollection or an idea to the wrong source (see FIGURE 6.16).

Part of memory is knowing where our memories came from. This is known as source memory, recall of when, where, and how information was acquired (Johnson, Hashtroudi, & Lindsay, 1993; Mitchell & Johnson, 2009; Schacter, Harbluk, & McLachlan, 1984). People sometimes correctly recall a fact they learned earlier or accurately recognize a person or object they have seen before but misattribute the source of this knowledge—just as happened to Tom Kessinger (Davies, 1988). Such misattribution could be the cause of déjà vu experiences, where you suddenly feel that you have been in a situation before even though you can’t recall any details. A present situation that is similar to a past experience may trigger a general sense of familiarity that is mistakenly attributed to having been in the exact situation previously (Brown, 2004; Reed, 1988).

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Individuals with damage to the frontal lobes are especially prone to memory misattribution errors (Schacter et al., 1984; Shimamura & Squire, 1987). This is probably because the frontal lobes play a significant role in effortful retrieval processes, which are required to dredge up the correct source of a memory. But we are all vulnerable to memory misattribution. Take the following test and there is a good chance that you will experience it for yourself. First, study the two lists of words presented in TABLE 6.1 by reading each word for about 1 second. When you are done, return to this paragraph for more instructions, but don’t look back at the table! Now try to recognize which of the following words appeared on the list you just studied: taste, bread, needle, king, sweet, thread. If you think that taste and thread were on the lists you studied, you’re right. And if you think that bread and king weren’t on those lists, you’re also right. But if you think that needle or sweet appeared on the lists, you’re dead wrong.

Most people make exactly the same mistake, claiming with confidence that they saw needle and sweet on the list. This mistaken feeling of familiarity, called false recognition, occurs because all the words in the lists are associated with needle or sweet. Seeing each word in the study list activates related words. Because needle and sweet are related to all of the associates, they become more activated than other words—so highly activated that only minutes later, people swear that they actually studied the words (Deese, 1959; Gallo, 2006, 2010; Roediger & McDermott, 1995, 2000). In fact, brain scanning studies using PET and fMRI show that many of the same brain regions are active during false recognition and true recognition, including the hippocampus (Cabeza et al., 2001; Schacter et al., 1996; see FIGURE 6.17). Similar results are obtained when people view a series of common objects (e.g., cars, umbrellas) and then are later shown a new object that looks like one they saw earlier: They often falsely recognize the similar new item, and many of the same brain regions become active during this kind of false recognition as during true recognition (Gutchess & Schacter, 2012; Slotnick & Schacter, 2004).

However, false recognition can be reduced (Schacter, Israel, & Racine, 1999). For example, recent evidence shows that when participants are given a choice between an object that they actually saw (e.g., a car) and a visually similar new object (a different car that looks like the one they saw), they almost always choose the car that they actually saw and thus avoid making a false recognition error (Guerin et al., 2012a, 2012b). When people experience a strong sense of familiarity about a person, object, or event but lack specific recollections, a potentially dangerous recipe for memory misattribution is in place, both in the laboratory and also in real-world situations involving eyewitness memory. Understanding this point may be a key to reducing the dangerous consequences of misattribution in eyewitness testimony.

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On October 4, 1992, a cargo plane crashed into an apartment building in a suburb of Amsterdam, killing 39 residents and all 4 members of the airline crew. The disaster dominated news in the Netherlands for days as people viewed footage of the crash scene and read about the catastrophe. Ten months later, Dutch psychologists asked university students: “Did you see the television film of the moment the plane hit the apartment building?” Fifty-five percent answered yes (Crombag, Wagenaar, & Van Koppen, 1996). All of this might seem perfectly normal except for one key fact: There was no television film of the moment when the plane actually crashed. The researchers had asked a suggestive question that implied that television film of the crash had been shown. Respondents may have viewed television film of the postcrash scene, and they may have read, imagined, or talked about what might have happened when the plane hit the building, but they most definitely did not see the actual crash. The suggestive question led participants to misattribute information from these or other sources to a film that did not exist. Suggestibility is the tendency to incorporate misleading information from external sources into personal recollections.

If misleading details can be implanted in people’s memories, is it also possible to suggest entire episodes that never occurred? The answer seems to be yes (Loftus, 1993, 2003). In one study, the research participant, a teenager named Chris, was asked by his older brother, Jim, to try to remember the time Chris had been lost in a shopping mall at age 5. He initially recalled nothing, but after several days, Chris produced a detailed recollection of the event. He recalled that he “felt so scared I would never see my family again” and remembered that a kindly old man wearing a flannel shirt found him crying (Loftus, 1993, p. 532). But according to Jim and other family members, Chris was never lost in a shopping mall. Of 24 participants in a larger study on implanted memories, approximately 25% falsely remembered being lost as a child in a shopping mall or in a similar public place (Loftus & Pickrell, 1995).

People develop false memories in response to suggestions for some of the same reasons memory misattribution occurs. We do not store all the details of our experiences in memory, making us vulnerable to accepting suggestions about what might have happened or should have happened. In addition, visual imagery plays an important role in constructing false memories (Goff & Roediger, 1998). Asking people to imagine an event like spilling punch all over the bride’s parents at a wedding increases the likelihood that they will develop a false memory of such a mishap (Hyman & Pentland, 1996).

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Suggestibility played an important role in a controversy that arose during the 1980s and 1990s concerning the accuracy of childhood memories that people recalled during psychotherapy. One highly publicized example involved a woman named Diana Halbrooks (Schacter, 1996). After a few months in psychotherapy, she began recalling disturbing incidents from her childhood—for example, that her mother had tried to kill her and that her father had abused her sexually. Although her parents denied that these events had ever occurred, her therapist encouraged her to believe in the reality of her memories. Eventually, Diana Halbrooks stopped therapy and came to realize that the “memories” she had recovered were inaccurate.

How could this happen? A number of the techniques used by psychotherapists to try to pull up forgotten childhood memories are clearly suggestive (Poole et al., 1995). Specifically, research has shown that imagining past events and hypnosis can help create false memories (Garry et al., 1996; Hyman & Pentland, 1996; McConkey, Barnier, & Sheehan, 1998). More recent studies show that memories that people remember spontaneously on their own are corroborated by other people at about the same rate as the memories of individuals who never forgot their abuse, whereas memories recovered in response to suggestive therapeutic techniques are virtually never corroborated by others (McNally & Geraerts, 2009).

In 2000, the outcome of a very close presidential race between George W. Bush and Al Gore was decided by the Supreme Court 5 weeks after the election had taken place. The day after the election (when the result was still in doubt), supporters of Bush and Gore were asked to predict how happy they would be after the outcome of the election was determined (Wilson, Meyers, & Gilbert, 2003). These same respondents reported how happy they felt with the outcome on the day after Al Gore conceded. And 4 months later, the participants recalled how happy they had been right after the election was decided.

Bush supporters were understandably happy the day after the Supreme Court decision. However, their retrospective accounts overestimated how happy they were at the time. Conversely, Gore supporters were not pleased with the outcome. But when polled 4 months after the election was decided, Gore supporters underestimated how happy they actually were at the time of the result. In both groups, recollections of happiness were at odds with existing reports of their actual happiness at the time (Wilson et al., 2003).

These results illustrate the problem of bias, the distorting influences of present knowledge, beliefs, and feelings on recollection of previous experiences. Sometimes, what people remember from their pasts says less about what actually happened than about what they think, feel, or believe now. Researchers have also found that our current moods can bias our recall of past experiences (Bower, 1981; Buchanan, 2007; Eich, 1995). So, in addition to helping you recall actual sad memories (as you saw earlier in this chapter), a sad mood can also bias your recollections of experiences that may not have been so sad.

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Sometimes, we exaggerate differences between what we feel or believe now and what we felt or believed in the past. For example, most of us would like to believe that our romantic attachments grow stronger over time. In one study, dating couples were asked, once a year for 4 years, to assess the present quality of their relationships and to recall how they felt in past years (Sprecher, 1999). Couples who stayed together for the 4 years recalled that the strength of their love had increased since they last reported on it. Yet their actual ratings over time did not show any increases in love and attachment. Objectively, the couples did not love each other more today than yesterday. But they did from the subjective perspective of memory. People were remembering the past as they wanted it to be rather than the way it was.

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The artist Melinda Stickney-Gibson awoke in her apartment to the smell of smoke. She jumped out of bed and saw black plumes rising through cracks in the floor. Raging flames had engulfed the entire building, and there was no chance to escape except by jumping from her third-floor window. Although she survived the fire and the fall, Melinda became overwhelmed by memories of the fire. When Melinda sat down in front of a blank canvas to start a new painting, her memories of that awful night intruded. Her paintings, which were previously bright, colorful abstractions, became dark meditations that included only black, orange, and ochre—the colors of the fire (Schacter, 1996).

Melinda Stickney-Gibson’s experiences illustrate memory’s seventh and most deadly sin, persistence: the intrusive recollection of events that we wish we could forget. Melinda’s experience is far from unique; persistence frequently occurs after disturbing or traumatic incidents, such as the fire that destroyed her home. Although being able to recall memories quickly is usually considered a good thing, in the case of persistence, that ability mutates into an unwelcome burden.

Intrusive memories are undesirable consequences of emotional experiences because emotional experiences generally lead to more vivid and enduring recollections than nonemotional experiences do. One line of evidence comes from the study of flashbulb memories, which are detailed recollections of when and where we heard about shocking events (Brown & Kulik, 1977). For example, most Americans can recall exactly where they were and how they heard about the September 11, 2001, terrorist attacks on the World Trade Center and the Pentagon—almost as if a mental flashbulb had gone off automatically and recorded the event in long-lasting and vivid detail (Kvavilashvili et al., 2009). Several studies have shown that flashbulb memories are not always entirely accurate, but they are generally better remembered than mundane news events from the same time (Larsen, 1992; Neisser & Harsch, 1992). Enhanced retention of flashbulb memories is partly attributable to the emotional arousal elicited by events such as the 9/11 terrorist attacks, and they are partly attributable to the fact that we tend to talk and think a lot about these experiences. Recall that semantic encoding enhances memory: When we talk about flashbulb experiences, we elaborate on them and thus further increase the memorability of those aspects of the experience that we discuss (Hirst et al., 2009).

Why do our brains succumb to persistence? A key player in the brain’s response to emotional events is the amygdala, shown in FIGURE 6.18. The amygdala influences hormonal systems that kick into high gear when we experience an arousing event; these stress-related hormones, such as adrenaline and cortisol, mobilize the body in the face of threat—and they also enhance memory for the experience. When people watch a slide show including emotional events (such as photos of a child being hit by a car) and also neutral events (a mother walking her child to school), there’s a better chance that they will later recall the emotional rather than the neutral events, and the better recall is correlated with heightened activity in the amygdala as they watched the emotional events (Cahill et al., 1996; Kensinger & Schacter, 2005, 2006). When people are given a drug that interferes with the amygdala-mediated release of stress hormones, their memory for the emotional material is no better than their memory for neutral material. Similarly, patients with amygdala damage remember the emotional and neutral material equally well (Cahill & McGaugh, 1998).

In many cases, there are clear benefits to forming strong memories for highly emotional events, particularly those that are life-threatening. In the case of persistence, though, such memories may be too strong—strong enough to interfere with other aspects of daily life.

You may have concluded that evolution has burdened us with an extremely inefficient memory system that is so prone to error that it often jeopardizes our well-being. Not so. The seven sins are the price we pay for the many benefits that memory provides, the occasional result of the normally efficient operation of the human memory system (Schacter, 2001b).

Consider transience, for example. Although it might sound great to remember all the details of every incident in your life, the fact is that it’s helpful and sometimes important to forget information that isn’t current, like an old phone number. If we didn’t gradually forget information over time, our minds would be cluttered with details that we no longer need (Bjork, 2011; Bjork & Bjork, 1988). Memory, in essence, makes a bet that when we haven’t used information recently, we probably won’t need it in the future. We win this bet more often than we lose it, making transience an adaptive property of memory. But we are acutely aware of the losses—the frustrations of forgetting—and are never aware of the wins. This is why people are often quick to complain about their memories: The drawbacks of forgetting are painfully evident, but the benefits of forgetting are hidden.

Similarly, absentmindedness and blocking can be frustrating, but they are side effects of our memory’s usually successful attempt to sort through incoming information, preserving details that are worthy of attention and recall, and discarding those that are less worthy.

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Memory misattribution and suggestibility both occur because we often fail to recall the details of exactly when and where we saw a face or learned a fact. Our memories carefully record such details only when we think they may be needed later, and most of the time, we are better off for it. Furthermore, we often use memories to anticipate possible future events. As discussed earlier, memory is flexible, allowing us to recombine elements of past experience in new ways so that we can mentally try out different versions of what might happen. But this very flexibility—a strength of memory—may sometimes produce misattribution errors in which elements of past experience are miscombined (Schacter & Addis, 2007; Schacter, Guerin, & St. Jacques, 2011). Bias skews our memories so that we depict ourselves in an overly favorable light, but it can produce the benefit of contributing to our overall sense of contentment, leading to greater psychological well-being (Taylor, 1989). Although persistence can cause us to be haunted by traumas that we’d be better off forgetting, overall, it is probably adaptive to remember threatening or traumatic events that could pose a threat to survival.

Although each of the seven sins can cause trouble in our lives, they have an adaptive side as well. You can think of the seven sins as costs we pay for benefits that allow memory to work as well as it does most of the time.

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