AP Psychology

Module 33 - Forgetting, Memory Construction, and Memory Improvement

LEARNING OBJECTIVES:

Forgetting

FOCUS QUESTION: Why do we forget?

Amid all the applause for memory - all the efforts to understand it, all the books on how to improve it - have any voices been heard in praise of forgetting? William James (1890, p. 680) was such a voice: "If we remembered everything, we should on most occasions be as ill off as if we remembered nothing." To discard the clutter of useless or out-of-date information-last year's locker combination, a friend's old phone number, restaurant orders already cooked and served-is surely a blessing. The Russian memory whiz S, whom we met at the beginning of Module 31, was haunted by his junk heap of memories. They dominated his consciousness. He had difficulty thinking abstractly-generalizing, organizing, evaluating. After reading a story, he could recite it but would struggle to summarize its gist.

A more recent case of a life overtaken by memory is "A. J.," whose experience has been studied and verified by a University of California at Irvine research team (Parker et a1., 2006). A. J., who has identified herself as Jill Price, compares her memory with "a running movie that never stops. It's like a split screen. I'll be talking to someone and seeing something else.... Whenever I see a date flash on the television (or anywhere for that matter) I automatically go back to that day and remember where I was, what I was doing, what day it fell on, and on and on and on and on. It is nonstop, uncontrollable, and totally exhausting." A good memory is helpful, but so is the ability to forget. If a memory-enhancing pill becomes available, it had better not be too effective.

More often, however, our unpredictable memory dismays and frustrates us. Memories are quirky. My own memory can easily call up such episodes as that wonderful first kiss with the woman I love, or trivial facts like the air mileage from London to Detroit. Then it abandons me when I discover I have failed to encode, store, or retrieve a student's name, or where I left my sunglasses.

Forgetting and the Two-Track Mind

English novelist and critic C. S. Lewis described the forgetting that plagues us all. We are bombarded every second by sensations, emotions, thoughts ... nine-tenths of which [we] must simply ignore. The past [is] a roaring cataract of billions upon billions of such moments: Anyone of them too complex to grasp in its entirety, and the aggregate beyond all imagination....At every tick of the clock, in every inhabited part of the world, an unimaginable richness and variety of 'history' falls off the world into total oblivion.

For some, memory loss is severe and permanent. Consider Henry Molaison (known as "H. M.," 1926-2008). For 55 years after having brain surgery to stop severe seizures, Molaison was unable to form new conscious memories. He was, as before his surgery, intelligent and did daily crossword puzzles. Yet, reported neuroscientist Suzanne Corkin (2005), "I've known H. M. since 1962, and he still doesn't know who I am." For about 20 seconds during a conversation he could keep something in mind. When distracted, he would lose what was just said or what had just occurred. Thus, he never could name the current president of the United States (Ogden, 2012).

Molaison suffered from anterograde amnesia - he could recall his past, but he could not form new memories. (Those who cannot recall their past - the old information stored in long-term memory - suffer from retrograde amnesia.)

Neurologist Oliver Sacks (1985, pp. 26-27) described another patient, Jimmie, who had anterograde amnesia resulting from brain damage. Jimmie had no memories - thus, no sense of elapsed time - beyond his injury in 1945.

When Jimmie gave his age as 19, Sacks set a mirror before him: "Look in the mirror and tell me what you see. Is that a 19-year-old looking out from the mirror?"
Jimmie turned ashen, gripped the chair, cursed, then became frantic: "What's going on? What's happened to me? Is this a nightmare? Am I crazy? Is this a joke?" When his attention was diverted to some children playing baseball, his panic ended, the dreadful mirror forgotten.
Sacks showed Jimmie a photo from National Geographic. "What is this?" he asked.
"It's the Moon," Jimmie replied.
"No, it's not," Sacks answered. "It's a picture of the Earth taken from the Moon."
"Doc, you're kidding? Someone would've had to get a camera up there!"
"Naturally. "
"Hell! You're joking - how the hell would you do that?" Jimmie's wonder was that of a bright young man from nearly 70 years ago reacting with amazement to his travel back to the future.

Careful testing of these unique people reveals something even stranger: Although incapable of recalling new facts or anything they have done recently, Molaison, Jimmie, and others with similar conditions can learn nonverbal tasks. Shown hard -to-find figures in pictures (in the Where's Waldo? series), they can quickly spot them again later. They can find their way to the bathroom, though without being able to tell you where it is. They can learn to read mirror-image writing or do a jigsaw puzzle, and they have even been taught complicated job skills (Schacter, 1992, 1996; Xu & Corkin, 2001). They can be classically conditioned. However, they do all these things with no awareness of having learned them.

Molaison and Jimmie lost their ability to form new explicit memories, but their automatic processing ability remained intact. Like Alzheimer's patients, whose explicit memories for new people and events are lost, they can form new implicit memories (Lustig & Buckner, 2004). They can learn how to do something, but they will have no conscious recall of learning their new skill. Such sad cases confirm that we have two distinct memory systems, controlled by different parts of the brain. For most of us, forgetting is a less drastic process. Let's consider some of the reasons we forget.

Encoding Failure

Much of what we sense we never notice, and what we fail to encode, we will never remember (see FIGURE 33.1). Age can affect encoding efficiency. The brain areas that jump into action when young adults encode new information are less responsive in older adults. This slower encoding helps explain age-related memory decline (Grady et a1., 1995).

But no matter how young we are, we selectively attend to few of the myriad sights and sounds continually bombarding us. When texting during class, students may fail to encode details that their more attentive classmates are encoding for next week's test. Without effort, many potential memories never form.

Storage Decay

Even after encoding something well, we sometimes later forget it. To study the durability of stored memories, Hermann Ebbinghaus (1885) learned more lists of nonsense syllables and measured how much he retained when relearning each list, from 20 minutes to 30 days later. The result, confirmed by later experiments, was his famous forgetting curve: The course of forgetting is initially rapid, then levels off with time (see FIGURE 33.2; Wixted & Ebbesen, 1991).

Harry Bahrick (1984) found a similar forgetting curve for Spanish vocabulary learned in school. Compared with those just completing a high school or college Spanish course, people 3 years out of school had forgotten much of what they had learned (see FIGURE 33.3). However, what people remembered then, they still remembered 25 and more years later. Their forgetting had leveled off.

One explanation for these forgetting curves is a gradual fading of the physical memory trace. Cognitive neuroscientists are getting closer to solving the mystery of the physical storage of memory and are increasing our understanding of how memory storage could decay. Like books you can't find in your high school library, memories may be inaccessible for many reasons. Some were never acquired (not encoded). Others were discarded (stored memories decay). And others are out of reach because we can't retrieve them.

Retrieval Failure

Often, forgetting is not memories faded but memories unretrieved. We store in long-term memory what's important to us or what we've rehearsed. But sometimes important events defy our attempts to access them (see FIGURE 33.4). How frustrating when a name lies poised on the tip of our tongue, just beyond reach. Given retrieval cues ("It begins with an M"), we may easily retrieve the elusive memory. Retrieval problems contribute to the occasional memory failures of older adults, who more frequently are frustrated by tip-of-the-tongue forgetting (Abrams, 2008).

Do you recall the gist of the sentence I asked you to remember in Module 32's discussion of making information personally meaningful? If not, does the word shark serve as a retrieval cue? Experiments show that shark (likely what you visualized) more readily retrieves the image you stored than does the sentence's actual word, fish (Anderson et al., 1976). (The sentence was "The fish attacked the swimmer.")

But retrieval problems occasionally stem from interference and, perhaps, from motivated forgetting.

INTERFERENCE

As you collect more and more information, your mental attic never fills, but it surely gets cluttered. Sometimes the clutter interferes, as new learning and old collide. Proactive (forard-acting) interference occurs when prior learning disrupts your recall of new information. Your well-rehearsed Facebook password may interfere with your retrieval of your newly learned copy machine code.

Retroactive (backward-acting) interference occurs when new learning disrupts recall of old information. If someone sings new lyrics to the tune of an old song, you may have trouble remembering the original words. It is rather like a second stone tossed in a pond, disrupting the waves rippling out from the first.

Information presented in the hour before sleep is protected from retroactive interference because the opportunity for interfering events is minimized (Diekelmann & Born, 2010; Nesca & Koulack, 1994). Researchers John Jenkins and Karl Dallenbach (1924) firs t discovered this in a now-classic experiment. Day after day, two people each learned some nonsense syllables, then tried to recall them after up to 8 hours of being awake or asleep at night. As FIGURE 33.5 shows, forgetting occurred more rapidly after being awake and involved with other activities. The investigators surmised that "forgetting is not so much a matter of the decay of old impressions and associations as it is a matter of interference, inhibition, or obliteration of the old by the new" (1924, p. 612).

The hour before sleep is a good time to commit information to memory (Scullin & McDaniel, 2010), though information presented in the seconds just before sleep is seldom remembered (Wyatt & Bootzin, 1994). If you're considering learning while sleeping, forget it. We have little memory for information played aloud in the room during sleep, although the ears do register it (Wood et al., 1992).

Old and new learning do not always compete with each other, of course. Previously learned information (Latin) often facilitates our learning of new information (French). This phenomenon is called positive transfer.

MOTIVATED FORGETTING

To remember our past is often to revise it. Years ago, the huge cookie jar in our kitchen was jammed with freshly baked chocolate chip cookies. Still more were cooling across racks on the counter. Twenty-four hours later, not a crumb was left. Who had taken them?

During that time, my wife, three children, and I were the only people in the house. So while memories were still fresh, I conducted a little memory test. Andy admitted wolfing down as many as 20. Peter thought he had eaten 15. Laura guessed she had stuffed her then-6year-old body with 15 cookies. My wife, Carol, recalled eating 6, and I remembered consuming 15 and taking 18 more to the office. We sheepishly accepted responsibility for 89 cookies. Still, we had not come close; there had been 160.

Why do our memories fail us? This happens in part because, as Carol Tavris and Elliot Aronson have pointed out, memory is an "unreliable, self-serving historian" (2007, p. 6). Consider one study, in which researchers told some participants about the benefits of frequent toothbrushing. Those individuals then recalled (more than others did) having frequently brushed their teeth in the preceding 2 weeks (Ross et al., 1981). FIGURE 33.6 reminds us that as we process information, we filter, alter, or lose much of it. So why were my family and I so far off in our estimates of the cookies we had eaten? Was it an encoding problem? (Did we just not notice what we had eaten?) Was it a storage problem? (Might our memories of cookies, like Ebbinghaus' memory of nonsense syllables, have melted away almost as fast as the cookies themselves?) Or was the information still intact but not retrievable because it would be embarrassing to remember?l

Sigmund Freud might have argued that our memory systems self-censored this information. He proposed that we repress painful or unacceptable memories to protect our self-concept and to minimize anxiety. But the repressed memory lingers, he believed, and can be retrieved by some later cue or during therapy. Repression was central to Freud's psychoanalytic theory (more on that in Module 55) and was a popular idea in mid-twentieth-century psychology and beyond. In one study, 9 in 10 university students agreed that "memories for painful experiences are sometimes pushed into unconsciousness" (Brovm et al., 1996). Some therapists assume it. Today, however, increasing numbers of memory researchers think repression rarely, if ever, occurs. People succeed in forgetting unwanted neutral information (yesterdays parking place), but it's harder to forget emotional events (Payne & Corrigan, 2007). Thus, we may have intrusive memories of the very traumatic experiences we would most like to forget.

Before You Move On

ASK YOURSELF: Most people, especially as they grow older, wish for a better memory. Is that true of you? Or do you more often wish you could better discard old memories?

TEST YOURSELF: Can you offer examples of proactive and retroactive interference?

Memory Construction Errors

FOCUS QUESTIONS: How do misinformation, imagination, and source amnesia influence our memory construction? How do we decide whether a memory is real or false?

Memory is not precise. Like scientists who infer a dinosaur's appearance from its remains, we infer our past from stored information plus what we later imagined, expected, saw, and heard. We don't just retrieve memories, we reweave them, noted Daniel Gilbert (2006, p. 79): "Information acquired after an event alters memory of the event." We often construct our memories as we encode them, and every time we "replay" a memory, we replace the original with a slightly modified version (Hardt et al., 2010). (Memory researchers call this reconsolidation.) So, in a sense, said Joseph LeDoux (2009), "your memory is only as good as your last memory. The fewer times you use it, the more pristine it is." This means that, to some degree, "all memory is false" (Bernstein & Loftus, 2009b). Let's examine some of the ways we rewrite our past.

Misinformation and Imagination Effects

In more than 200 experiments, involving more than 20,000 people, Elizabeth Loftus has shown how eyewitnesses reconstruct their memories after a crime or an accident. In one experiment, two groups of people watched a film of a traffic accident and then answered questions about what they had seen (Loftus & Palmer, 1974). Those asked, "About how fast were the cars going when they smashed into each other?" gave higher speed estimates than those asked, "About how fast were the cars going when they hit each other?" A week later, when asked whether they recalled seeing any broken glass, people who had heard smashed were more than twice as likely to report seeing glass fragments (see FIGURE 33.7). In fact, the film showed no broken glass.

In many follow-up experiments around the world, others have witnessed an event, received or not received misleading information about it, and then taken a memory test. The repeated result is a misinformation effect: Exposed to misleading information, we tend to misremember. A yield sign becomes a stop sign, hammers become screwdrivers, Coke cans become peanut cans, breakfast cereal becomes eggs, and a clean-shaven man morphs into a m.an with a mustache (Loftus et aL 1992). So powerful is the misinformation effect that it can influence later attitudes and behaviors (Bernstein & Loftus, 2009).

Just hearing a vivid retelling of an event can implant false memories. One experiment falsely suggested to some Dutch university students that, as children, they became ill after eating spoiled egg salad (Geraerts et al., 2008). After absorbing that suggestion, a significant minority were less likely to eat egg-salad sandwiches, both immediately and 4 months later.

Even repeatedly imagining nonexistent actions and events can create false memories. American and British university students were asked to imagine certain childhood events, such as breaking a window with their hand or having a skin sample removed from a finger. One in four of them later recalled the imagined event as something that had really happened (Gany et al., 1996; Mazzoni & Memon, 2003).

Digitally altered photos have also produced this imagination inflation. In experiments, researchers have altered photos from a family album to show some fancily members taking a hot-air balloon ride. After viewing these photos (rather than photos showing just the balloon), children reported more false memories and indicated high confidence in those memories. When interviewed several days later, they reported even richer details of their false memories (Strange et al., 2008; Wade et aL 2002).

In British and Canadian university surveys, nearly one-fourth of students have reported autobiographical memories that they later realized were not accurate (Mazzoni et al., 2010).

I empathize. For decades, my cherished earliest memory was of my parents getting off the bus and walking to our house, bringing my baby brother home from the hospital. When, in middle age, I shared that memory with my father, he assured me they did not bring their newborn home on the Seattle Transit System. The human mind, it seems, comes with builtin Photoshopping software.

Source Amnesia

Among the frailest parts of a memory is its source. We may recognize someone but have no idea where we have seen the person. We may dream an event and later be unsure whether it really happened. We may misrecall how we learned about something (Henkel et al., 2000). Psychologists are not immune to the process. Famed child psychologist Jean Piaget was startled as an adult to learn that a vivid, detailed memory from his childhood - a nursemaid's thwarting his kidnapping - was utterly false. He apparently constructed the memory from repeatedly hearing the story (which his nursemaid, after undergoing a religious conversion, later confessed had never happened). In attributing his "memory" to his own experiences, rather than to his nursemaid's stories, Piaget exhibited source amnesia (also called source misattribution). Misatttibution is at the heart of many false memories. Authors and songwriters sometimes suffer from it. They think an idea came from their own creative imagination, when in fact they are unintentionally plagiarizing something they earlier read or heard.

Debra Poole and Stephen Lindsay (1995, 2001, 2002) demonstrated source amnesia among preschoolers. They had the children interact with "Mr. Science," who engaged them in activities such as blowing up a balloon with baking soda and vinegar. Three months later, on three successive days, their parents read them a story describing some things the children had experienced with Mr. Science and some they had not. When a new interviewer asked what Mr. Science had done with them - "Did Mr. Science have a machine with ropes to pull?" - 4 in 10 children spontaneously recalled him doing things that had happened only in the story.

Source amnesia also helps explain déjà vu (French for "already seen"). Two-thirds of us have experienced this fleeting, eerie sense that "I've been in this exact situation before." It happens most commonly to well-educated, imaginative young adults, especially when tired or stressed (Brown, 2003, 2004; McAneny, 1996). Some wonder, "How could I recognize a situation I'm experiencing for the first time?" Others may think of reincarnation ("I must have experienced this in a previous life") or precognition ("1 viewed this scene in my mind before experiencing it").

The key to déjà vu seems to be familiarity with a stimulus without a clear idea of where we encountered it before (Cleary, 2008). Normally, we experience a feeling of familiarity (thanks to temporal lobe processing) before we consciously remember details (thanks to hippocampus and frontal lobe processing). When these functions (and brain regions) are out of sync, we may experience a feeling of familiarity without conscious recall. Our amazing brains try to make sense of such an improbable situation, and we get an eerie feeling that we're reliving some earlier part of our life. After all, the situation is familiar, even though we have no idea why. Our source amnesia forces us to do our best to make sense of an odd moment.

Discerning True and False Memories

Because the misinformation effect and source amnesia happen outside our awareness, it is nearly impossible to sift suggested ideas out of the larger pool of real memories (Schooler et al., 1986). Perhaps you can recall describing a childhood experience to a friend and filling in memory gaps with reasonable guesses and assumptions. We all do it, and after more retellings, those guessed details-now absorbed into our memories-may feel as real as if we had actually experienced them (Roediger et a1., 1993). Much as perceptual illusions may seem like real perceptions, unreal memories feel like real memories.

False memories can be very persistent. Imagine that I were to read aloud a list of words such as candy, sugar, honey, and taste. Later, I ask you to recognize the presented words from a larger list. If you are at all like the people tested by Henry Roediger and Kathleen McDermott (1995), you would err three out of four times - by falsely remembering a non-presented similar word, such as sweet.We more easily remember the gist than the words themselves.

Memory construction helps explain why 79 percent of 200 convicts exonerated by later DNA testing had been misjudged based on faulty eyewitness identification (Garrett, 2008). It explains why "hypnotically refreshed" memories of crimes so easily incorporate errors, some of which originate with the hypnotist's leading questions ("Did you hear loud noises?"). It explains why dating partners who fell in love have overestimated their first impressions of one another ("It was love at first sight"), while those who broke up underestimated their earlier liking ("We never really clicked") (McFarland & Ross, 1987). How people feel today tends to be how they recall they have always felt (Mazzoni &Vannucci, 2007; and recall from Module 4 our tendency to hindsight bias). As George Vaillant (1977, p. 197) noted after following adult lives through time, "It is all too common for caterpillars to become butterflies and then to maintain that in their youth they had been little butterflies. Maturation makes liars of us all."

Children's Eyewitness Recall

FOCUS QUESTIONS: How reliable are young children's eyewitness descriptions, and why are reports of repressed and recovered memories so hotly debated?

If memories can be sincere, yet sincerely wrong, might children's recollections of sexual abuse be prone to error? "It would be truly awful to ever lose sight of the enormity of child abuse," observed Stephen Ceci (1993). Yet Ceci and Maggie Bruck's (1993, 1995) studies of children's memories have made them aware of how easily children's memories can be molded. For example, they asked 3-year-olds to show on anatomically correct dolls where a pediatrician had touched them. Of the children who had not received genital examinations, 55 percent pointed to either genital or anal areas.

In other experiments, the researchers studied the effect of suggestive interviewing techniques (Bruck & Ceci, 1999, 2004). In one study, children chose a card from a deck of possible happenings, and an adult then read the card to them. For example, "Think real hard, and tell me if this ever happened to you. Can you remember going to the hospital with a mousetrap on your finger?" In interviews, the same adult repeatedly asked children to think about several real and fictitious events. After 10 weeks of this, a new adult asked the same question. The stunning result: 58 percent of preschoolers produced false (often vivid) stories regarding one or more events they had never experienced (Ceci et al., 1994). Here's one of those stories:

My brother Colin was trying to get Blowtorch [an action figure] from me, and I wouldn't let him take it from me, so he pushed me into the wood pile where the mousetrap was. And then my finger got caught in it. And then we went to the hospital, and my mommy, daddy, and Colin drove me there, to the hospital in our van, because it was far away. And the doctor put a bandage on this finger.

Given such detailed stories, professional psychologists who specialize in interviewing children could not reliably separate the real memories from the false ones. Nor could the children themselves. The above child, reminded that his parents had told him several times that the mousetrap incident never happened - that he had imagined it - protested, "But it really did happen. I remember it!" In another experiment, preschoolers merely overheard an erroneous remark that a magician's missing rabbit had gotten loose in their classroom. Later, when the children were suggestively questioned, 78 percent of them recalled actually seeing the rabbit (Principe et al., 2006). "[The] research leads me to worry about the possibility of false allegations. It is not a tribute to one's scientific integrity to walk down the middle of the road if the data are more to one side," said Ceci (1993).

Does this mean that children can never be accurate eyewitnesses? No. When questioned about their experiences in neutral words they understood, children often accurately recalled what happened and who did it (Goodman, 2006; Howe, 1997; Pipe, 1996). And when interviewers used less suggestive, more effective techniques, even 4-to 5-year-old children produced more accurate recall (Holliday & Albon, 2004; Pipe et aI., 2004). Children were especially accurate when they had not talked with involved adults prior to the interview and when their disclosure was made in a first interview with a neutral person who asked nonleading questions.

Repressed or Constructed Memories of Abuse?

The research on source amnesia and the misinformation effect raises concerns about therapist-guided "recovered" memories. There are two tragedies related to adult recollections of child abuse. One happens when people don't believe abuse survivors who tell their secret. The other happens when innocent people are falsely accused.

Some well-intentioned therapists have reasoned with patients that "people who've been abused often have your symptoms, so you probably were abused. Let's see if, aided by hypnosis or drugs, or helped to dig back and visualize your trauma, you can recover it." Patients exposed to such techniques may then form an image of a threatening person. With further visualization, the image grows more vivid. The patient ends up stunned, angry, and ready to confront or sue the remembered abuser. The accused person (often a parent or relative) is equally stunned and devastated, and vigorously denies the accusation.

Critics are not questioning most therapists' professionalism. Nor are they questioning the accusers' sincerity; even if false, their memories are heartfelt. Critics' charges are specifically directed against clinicians who use "memory work" techniques, such as "guided imagery," hypnosis, and dream analysis to recover memories. "Thousands of families were cruelly ripped apart," with "previously loving adult daughters" suddenly accusing fathers (Gardner, 2006). Irate clinicians have countered that those who argue that recovered memories of abuse never happen are adding to abused people's trauma and playing into the hands of child molesters.

In an effort to find a sensible common ground that might resolve psychology's "memory war," professional organizations (the American Medical, American Psychological, and American Psychiatric Associations; the Australian Psychological Society; the British Psychological Society; and the Canadian Psychiatric Association) have convened study panels and issued public statements. Those committed to protecting abused children and those committed to protecting wrongly accused adults have agreed on the following:

So, does repression of threatening memories ever occur? Or is this concept - the cornerstone of Freud's theory and of so much popular psychology - misleading? In Modules 55 and 56, we will return to this hotly debated issue. For now, this much appears certain: The most common response to a traumatic experience (witnessing a loved one's murder, being terrorized by a hijacker or a rapist, losing everything in a natural disaster) is not banishment of the experience into the unconscious. Rather, such experiences are typically etched on the mind as vivid, persistent, haunting memories (Porter & Peace, 2007). As Robert Kraft (2002) said of the experience of those trapped in the Nazi death camps, "Horror sears memory, leaving ... the consuming memories of atrocity."

Before You Move On

ASK YOURSELF: Could you be an impartial jury member in a trial of a parent accused of sexual abuse based on a recovered memory, or of a therapist being sued for creating a false memory of abuse? Why or why not?

TEST YOURSELF: How would source amnesia affect us if we were to remember all of our waking experiences as well as all of our dreams?

Improving Memory

FOCUS QUESTIONS: How can you use memory research findings to do better in this and other courses?

Biology's findings benefit medicine. Botany'S findings benefit agriculture. So, too, can psychology's research on memory benefit education. Here, for easy reference, is a summary of some research-based suggestions that could help you remember information when you need it. The SQ3R (Survey, Question, Read, Retrieve, Review) study technique introduced in Module 2 incorporates several of these strategies:

Before You Move On

ASK YOURSELF: Which of the study and memory strategies suggested in this section will work best for you?

TEST YOURSELF: What are the recommended memory strategies you just read about? (One advised rehearsing to-be-remembered material. What were the others?)