Module 31-32 Studying and Encoding Memories PDF

Module 31 Studying and Encoding Memories LEARNING TARGETS 31-1 Define memory, and explain how memory is measured. 31-2 Discuss how psychologists describe the human memory system. 31-3 Describe the differences between explicit and implicit memories. 31-4 Discuss...

Module 31 Studying and Encoding Memories LEARNING TARGETS 31-1 Define memory, and explain how memory is measured. 31-2 Discuss how psychologists describe the human memory system. 31-3 Describe the differences between explicit and implicit memories. 31-4 Discuss the information we process automatically. 31-5 Explain how sensory memory works. 31-6 Describe our short-term and working memory capacity. 31-7 Describe the effortful processing strategies that help us remember new information. 31-8 Discuss the levels of processing and their effect on encoding. Be thankful for memory. We take it for granted, except when it malfunctions. But it is our memory that accounts for time and defines our life. It is our memory that enables us to recognize family, speak our language, and find our way home. It is our memory that enables us to enjoy an experience and then mentally replay and enjoy it again. It is our memory that enables us to build histories with those we love. And it is our memory that occasionally pits us against those whose offenses we cannot forget. Our shared memories help bind us together as Irish or Icelandic, Serbian or Samoan. 878  In large part, we are what we remember. Without memory—our storehouse of accumulated learning—there would be no savoring of past joys, no guilt or anger over painful recollections. We would instead live in an enduring present, each moment fresh. Each person would be a stranger, every language foreign, every task—dressing, eating, biking—a new challenge. You would even be a stranger to yourself, lacking that continuous sense of self that extends from your distant past to your momentary present. 879 Studying Memory 31-1 What is memory, and how is it measured? Memory is learning that persists over time; it is information that has been acquired and stored and can be retrieved. Research on memory’s extremes has helped us understand how memory works. At age 92, my [DM’s] father suffered a small stroke that had but one peculiar effect. He was as mobile as before. His genial personality was intact. He knew us and enjoyed poring over family photo albums and reminiscing about his past. But he had lost most of his ability to lay down new memories of conversations and everyday episodes. He could not tell me what day of the week it was, or what he’d had for lunch. Told repeatedly of his brother-in- law’s recent death, he was surprised and saddened each time he heard the news. memory the persistence of learning over time through the encoding, storage, and retrieval of information. Extreme forgetting Alzheimer’s disease severely damages the brain, and in the process, strips away memory. Some disorders slowly strip away memory. Alzheimer’s disease begins as difficulty remembering new information and progresses into an inability 880 to do everyday tasks. Family members and close friends become strangers; complex speech devolves to simple sentences; the brain’s memory centers weaken and wither (Desikan et al., 2009). Over several years, someone with Alzheimer’s may become unknowing and unknowable. Lost memory strikes at the core of our humanity, leaving people robbed of a sense of joy, meaning, and companionship. (Without your memory, would you be you?) At the other extreme are people who would win gold medals in a memory Olympics. Russian journalist Solomon Shereshevskii, or S, had merely to listen while other reporters scribbled notes (Luria, 1968). The average person could repeat back a string of about 7—maybe even 9— digits. S could repeat up to 70, if they were read about 3 seconds apart in an otherwise silent room. Moreover, he could recall digits or words backward as easily as forward. His accuracy was unerring, even when recalling a list 15 years later. “Yes, yes,” he might recall. “This was a series you gave me once when we were in your apartment.... You were sitting at the table and I in the rocking chair.... You were wearing a gray suit....” AP® EXAM TIP The next three modules deal with memory. Not only is this a significant topic on the AP® exam, but it is also, for students, one of psychology’s most practical topics! As you read, think about how you can apply what you’re learning about encoding, storing, and retrieving information—and become a better student. Amazing? Yes, but consider your own impressive memory. You remember countless faces, places, and happenings; tastes, smells, and textures; voices, sounds, and songs. In one study, students listened to snippets—a mere four-tenths of a second—from popular songs. How often did they recognize the artist and song? More than 25 percent of the time (Krumhansl, 2010). We often recognize songs as quickly as we recognize 881 a familiar voice. “ If any one faculty of our nature may be called more wonderful than the rest, I do think it is memory.” Jane Austen, Mansfield Park, 1814 So, too, with faces and places. Imagine viewing more than 2500 slides of faces and places for 10 seconds each. Later, you see 280 of these slides, paired with others you’ve never seen. Actual participants in this experiment recognized 90 percent of the slides they had viewed in the first round (Haber, 1970). In a follow-up experiment, people exposed to 2800 images for only 3 seconds each spotted the repeats with 82 percent accuracy (Konkle et al., 2010). Look for a target face in a sea of faces and you later will recognize other faces from the scene as well (Kaunitz et al., 2016). Some super-recognizers display an extraordinary ability to recognize faces. Eighteen months after viewing a video of an armed robbery, one such police officer spotted and arrested the robber walking on a busy street (Davis et al., 2013). And it’s not just humans who have shown remarkable memory for faces. Sheep can learn to remember faces (Figure 31.1). And so can at least one fish species—as demonstrated by their spitting at familiar faces to trigger a food reward (Newport et al., 2016). Figure 31.1 Other animals also display face smarts After food rewards are repeatedly associated with some sheep faces, 882  but not with others, sheep remember the food-associated faces for two years (Kendrick & Feng, 2011). How do we humans accomplish such memory feats? How does our brain pluck information out of the world around us and tuck it away for later use? How can we remember things we have not thought about for years, yet forget the name of someone we just met? How are memories stored in our brain? Why will you be likely, later in this module, to misrecall this sentence: “The angry rioter threw the rock at the window”? In this and the next two modules, we’ll consider these fascinating questions and more. Measuring Retention To a psychologist, evidence that learning persists includes these three retention measures: recall—retrieving information that is not currently in your conscious awareness but that was learned at an earlier time. A fill-in-the-blank question tests your recall. recognition—identifying items previously learned. A multiple-choice question tests your recognition. relearning—learning something more quickly when you learn it a second or later time. When you study for a final exam or engage a language used in early childhood, you will relearn the material more easily than you did initially. recall a measure of memory in which the person must retrieve information learned earlier, as on a fill-in-the-blank test. recognition a measure of memory in which the person identifies items previously learned, as on a multiple-choice test. 883  relearning a measure of memory that assesses the amount of time saved when learning material again. Long after you cannot recall most of the people in your high school graduating class, you may still be able to recognize their yearbook pictures and spot their names in a list of names. In one experiment, people who had graduated 25 years earlier could not recall many of their old classmates. But they could recognize 90 percent of their pictures and names (Bahrick et al., 1975). If you are like most students, you, too, could probably recognize more names of Snow White’s seven dwarfs than you could recall (Miserandino, 1991). Our recognition memory is impressively quick and vast. “Is your friend wearing a new or old outfit?” “Old.” “Is this five-second movie clip from a film you’ve ever seen?” “Yes.” “Have you ever seen this person before—this minor variation on the same old human features (two eyes, one nose, and so on)?” “No.” Before the mouth can form our answer to any of millions of such questions, the mind knows, and knows that it knows. Our response speed when recalling or recognizing information indicates memory strength, as does our speed at relearning. Pioneering memory researcher Hermann Ebbinghaus (1850–1909) showed this over a century ago, using nonsense syllables. He randomly selected a sample of syllables, practiced them, and tested himself. To get a feel for his experiments, rapidly read aloud, eight times over, the following list (from Baddeley, 1982), then look away and try to recall the items: JIH, BAZ, FUB, YOX, SUJ, XIR, DAX, LEQ, VUM, PID, KEL, WAV, TUV, ZOF, GEK, HIW. 884  Remembering things past Even if Taylor Swift and Bruno Mars had not become famous, their high school classmates would most likely still recognize them in these photos. The day after learning such a list, Ebbinghaus could recall few of the syllables. But they weren’t entirely forgotten. As Figure 31.2 portrays, the more frequently he repeated the list aloud on Day 1, the less time he required to relearn the list on Day 2. Additional rehearsal of verbal information can produce overlearning, which increases retention— especially when practice is distributed over time. For students, this means that it helps to rehearse course material even after you know it. 885  Figure 31.2 Ebbinghaus’ retention curve Ebbinghaus found that the more times he practiced a list of nonsense syllables on Day 1, the less time he required to relearn it on Day 2. Speed of relearning is one measure of memory retention. The point to remember: Tests of recognition and of time spent relearning demonstrate that we remember more than we can recall. Check Your Understanding Ask Yourself Imagine having a disease that significantly impaired your memory. Now, imagine having a record-setting ability to remember, like Russian journalist Solomon Shereshevskii. How would each affect your daily routine? Test Yourself Multiple-choice questions test our ______________. Fill-in-the-blank questions test our ______________. If you want to be sure to remember what you’re learning for an upcoming test, would it be better to use recall or recognition to check your memory? Why? 886  Answers to the Test Yourself questions can be found in Appendix E at the end of the book. Memory Models 31-2 How do psychologists describe the human memory system? Architects make virtual house models to help clients imagine their future homes. Similarly, psychologists create memory models that, even if imperfect, are useful. Such models help us think about how our brain forms and retrieves memories. An information-processing model likens human memory to computer operations. Thus, to remember any event, we must get information into our brain, a process called encoding. retain that information, a process called storage. later get the information back out, a process called retrieval. encoding the process of getting information into the memory system—for example, by extracting meaning. storage the process of retaining encoded information over time. retrieval the process of getting information out of memory storage. Like all analogies, computer models have their limits. Our memories are less literal and more fragile than a computer’s. Most computers also process information sequentially, even while alternating between tasks. Our agile brain processes many things simultaneously (some of them unconsciously) by means of parallel processing. To focus on this multitrack processing, one information-processing model, connectionism, views memories as products of interconnected neural networks. Specific 887 memories arise from particular activation patterns within these networks. Every time you learn something new, your brain’s neural connections change, forming and strengthening pathways that allow you to interact with and learn from your constantly changing environment. parallel processing processing many aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions. To explain our memory-forming process, Richard Atkinson and Richard Shiffrin (1968, 2016) proposed a three-stage model: 1. We first record to-be-remembered information as a fleeting sensory memory. 2. From there, we process information into short-term memory, where we encode it through rehearsal. 3. Finally, information moves into long-term memory for later retrieval. sensory memory the immediate, very brief recording of sensory information in the memory system. short-term memory activated memory that holds a few items briefly, such as digits of a phone number while calling, before the information is stored or forgotten. long-term memory the relatively permanent and limitless storehouse of the memory system. Includes knowledge, skills, and experiences. This model has since been updated (Figure 31.3) with important newer concepts, including working memory and automatic processing. 888  Figure 31.3 A modified three-stage processing model of memory Atkinson and Shiffrin’s classic three-step model helps us to think about how memories are processed, but today’s researchers recognize other ways long-term memories form. For example, some information slips into long-term memory via a “back door,” without our consciously attending to it (automatic processing). And so much active processing occurs in the short-term memory stage that many now prefer the term working memory. Working Memory Alan Baddeley and others (Baddeley, 2002; Barrouillet et al., 2011; Engle, 2002) extended Atkinson and Shiffrin’s initial view of short-term memory as a space for briefly storing recent thoughts and experiences. This stage is not just a temporary shelf for holding incoming information. It’s an active scratchpad where your brain actively processes information by making sense of new input and linking it with long-term memories. It also works in the opposite direction, by processing already stored information. Whether we hear “eye-screem” as ice cream or I scream depends on how the context and our experience guide our interpreting and encoding of the sounds. To focus on the active processing that takes place in this middle stage, psychologists use the term working memory. Right now, you are using your working memory to link the information you’re reading with your previously stored information (Cowan, 2010, 2016; Kail & Hall, 2001). working memory a newer understanding of short-term memory that adds conscious, active processing of incoming auditory and visual information, and of information 889  retrieved from long-term memory. For most of you, what you are reading enters working memory through vision. You might also repeat the information using auditory rehearsal. As you integrate these memory inputs with your existing long-term memory, your attention is focused (recall from Module 16 the mental spotlight that we call selective attention). In Baddeley’s (2002) model, a central executive coordinates this focused processing (Figure 31.4). Figure 31.4 Working memory Alan Baddeley’s (2002) model of working memory, simplified here, includes visual and auditory rehearsal of new information. A hypothetical central executive (manager) focuses our attention, and pulls information from long-term memory to help make sense of new information. AP® EXAM TIP You will see several versions of Figure 31.3 as you work your way through Modules 31, 32, and 33. Pay attention! This model may look confusing now, but it will make more and more sense as its components are described in detail. 890  The three stages of memory and the encoding process will be important to know for the AP® exam. Without focused attention, information often fades. If you think you can look something up later, you attend to it less and forget it more quickly. In one experiment, people read and typed new bits of trivia they would later need, such as “An ostrich’s eye is bigger than its brain.” If they knew the information would be available online, they invested less energy and remembered it less well (Sparrow et al., 2011; Wegner & Ward, 2013). Online, out of mind. Check Your Understanding Ask Yourself How have you used the three parts of your memory system (encoding, storage, and retrieval) in learning something new today? Test Yourself Memory includes (in alphabetical order) long-term memory, sensory memory, and working/short-term memory. What’s the correct order of these in the three-stage memory model? How does the working memory concept update the classic Atkinson-Shiffrin three-stage information-processing model? What are two basic functions of working memory? Answers to the Test Yourself questions can be found in Appendix E at the end of the book. 891 Encoding Memories Flip It Video: Improving Encoding Dual-Track Memory: Effortful Versus Automatic Processing 31-3 How do explicit and implicit memories differ? Atkinson and Shiffrin’s model focused on how we process our explicit memories—the facts and experiences that we can consciously know and declare (thus, also called declarative memories). We encode explicit memories through conscious effortful processing. But our mind has a second, unconscious track. Behind the scenes, other information skips the conscious encoding track and barges directly into storage. This automatic processing, which happens without our awareness, produces implicit memories (also called nondeclarative memories). explicit memory retention of facts and experiences that one can consciously know and “declare.” (Also called declarative memory.) effortful processing encoding that requires attention and conscious effort. automatic processing unconscious encoding of incidental information, such as space, time, and frequency, and of well-learned information, such as word meanings. implicit memory retention of learned skills or classically conditioned associations independent of conscious recollection. (Also called nondeclarative memory.) Our two-track mind, then, helps us encode, retain, and retrieve information through both effortful and automatic tracks. Let’s begin by 892 seeing how automatic processing assists the formation of implicit memories. Automatic Processing and Implicit Memories 31-4 What information do we process automatically? Our implicit memories include procedural memory for automatic skills (such as how to ride a bike) and classically conditioned associations among stimuli. If attacked by a dog in childhood, years later you may, without recalling the conditioned association, automatically tense up as a dog approaches. Without conscious effort you also automatically process information about space. While studying, you often encode the place on a page or in your notebook where certain material appears; later, when you want to retrieve the information, you may visualize its location. time. While going about your day, you unintentionally note the sequence of its events. Later, realizing you’ve left your backpack somewhere, the event sequence your brain automatically encoded will enable you to retrace your steps and find the backpack. frequency. You effortlessly keep track of how many times things happen, as when you realize, “This is the third time I’ve run into her today.” Our two-track mind engages in impressively efficient information processing. As one track automatically tucks away routine details, the other track is free to focus on conscious, effortful processing. This reinforces an important principle introduced in Module 18’s description of parallel processing: Mental feats such as vision, thinking, and memory may seem to be single abilities, but they are not. Rather, we split information into different components for separate and simultaneous processing. 893 Effortful Processing and Explicit Memories Automatic processing happens effortlessly. When you see words in your native language, perhaps on the side of a delivery truck, you can’t help but read them and register their meaning. Learning to read wasn’t automatic. You may recall working hard to pick out letters and connect them to certain sounds. But with experience and practice, your reading became automatic. Imagine now learning to read sentences in reverse:.citamotua emoceb nac gnissecorp luftroffE At first, this requires effort, but after enough practice, you would also perform this task much more automatically. We develop many skills in this way: driving, texting, and speaking a new language. Sensory Memory 31-5 How does sensory memory work? Sensory memory (recall Figure 31.3) feeds our active working memory, recording momentary images of scenes or echoes of sounds. How much of this page could you sense and recall with less exposure than a lightning flash? In one experiment, people viewed three rows of three letters each, for only one-twentieth of a second (Figure 31.5). After the nine letters disappeared, they could recall only about half of them. Figure 31.5 Total recall—briefly When George Sperling (1960) flashed a group of letters similar to this for one-twentieth of a second, people could recall only about half the letters. But when signaled to recall a particular row immediately after the letters had disappeared, they could do so with near-perfect 894  accuracy. Was it because they had insufficient time to glimpse them? No. People actually could see and recall all the letters, but only momentarily. Rather than ask them to recall all nine letters at once, researcher George Sperling sounded a high, medium, or low tone immediately after flashing the nine letters. This tone directed participants to report only the letters of the top, middle, or bottom row, respectively. Now they rarely missed a letter, showing that all nine letters were momentarily available for recall. Sperling’s experiment demonstrated iconic memory, a fleeting sensory memory of visual stimuli. For a few tenths of a second, our eyes register a picture-image memory of a scene, and we can recall any part of it in amazing detail. But delaying the tone signal by more than half a second caused the image to fade and memory to suffer. We also have an impeccable, though fleeting, memory for auditory stimuli, called echoic memory (Cowan, 1988; Lu et al., 1992). Picture yourself in class, as your attention drifts to thoughts of the weekend. If your mildly irked teacher tests you by asking, “What did I just say?” you can recover the last few words from your mind’s echo chamber. Auditory echoes tend to linger for 3 or 4 seconds. iconic memory a momentary sensory memory of visual stimuli; a picture-image memory lasting no more than a few tenths of a second. echoic memory a momentary sensory memory of auditory stimuli; if attention is elsewhere, sounds and words can still be recalled within 3 or 4 seconds. Short-Term Memory Capacity 31-6 What is our short-term and working memory capacity? 895 Recall that short-term memory refers to what we can briefly retain. The related idea of working memory also includes our active processing, as our brain makes sense of incoming information and links it with stored memories. What are the limits of what we can hold in this middle, short- term stage? George Miller (1956) proposed that we can store about seven pieces of information (give or take two) in short-term memory. Miller’s magical number seven is psychology’s contribution to the list of magical sevens— the seven wonders of the world, the seven seas, the seven deadly sins, the seven colors of the rainbow, the seven musical scale notes, the seven days of the week—seven magical sevens. Other researchers have confirmed that we can, if nothing distracts us, recall about seven digits. But the number varies by task; we tend to remember about six letters and only about five words (Baddeley et al., 1975; Cowan, 2015). And how quickly do our short-term memories disappear? To find out, Lloyd Peterson and Margaret Peterson (1959) asked people to remember three-consonant groups, such as CHJ. To prevent rehearsal, the researchers asked them, for example, to start at 100 and begin counting aloud backward by threes. After 3 seconds, people recalled the letters only about half the time; after 12 seconds, they seldom recalled them at all (Figure 31.6). Without the active processing that we now understand to be a part of our working memory, short-term memories have a limited life. 896  Figure 31.6 Short-term memory decay Unless rehearsed, verbal information may be quickly forgotten. Working memory capacity varies, depending on age and other factors. Compared with children and older adults, young adults have a greater working memory capacity. Having a large working memory capacity—the ability to juggle multiple items while processing information—tends to aid information retention after sleeping and creative problem solving (De Dreu et al., 2012; Fenn & Hambrick, 2012; Wiley & Jarosz, 2012). But whatever our age, we do better and more efficient work when focused, without distractions, on one task at a time. The bottom line: It’s probably a bad idea to try to watch TV, text your friends, and write a psychology paper all at the same time, with your attention switching between them (Willingham, 2010). Effortful Processing Strategies 31-7 What are some effortful processing strategies that can help us remember new information? Several effortful processing strategies can boost our ability to form new memories. Later, when we try to retrieve a memory, these strategies can 897 make the difference between success and failure. CHUNKING Glance for a few seconds at the first set of letters (row 1) in Figure 31.7, then look away and try to reproduce what you saw. Impossible, yes? But you can easily reproduce set 2, which is no less complex. Similarly, you will probably remember sets 4 and 6 more easily than the same elements in sets 3 and 5. As this demonstrates, chunking information—organizing items into familiar, manageable units—enables us to recall it more easily. Try remembering 43 individual numbers and letters. It would be impossible, unless chunked into, say, seven meaningful chunks, such as “Try remembering 43 individual numbers and letters.” Figure 31.7 Chunking effects Organizing information into meaningful units, such as letters, words, and phrases, helps us recall it more easily (Hintzman, 1978). chunking organizing items into familiar, manageable units; often occurs automatically. Chunking usually occurs so naturally that we take it for granted. If you are a native English speaker, you can reproduce perfectly the 150 or so line segments that make up the words in the three phrases of set 6 in Figure 31.7. It would astonish someone unfamiliar with the language. We [DM 898 and ND], who do not speak Chinese, are similarly awed by a Chinese reader’s ability to glance at Figure 31.8 and then reproduce all the strokes. Even the most committed sports fan may be amazed by a varsity basketball player’s recall of all the players’ positions after a 4-second peek at a basketball play (Allard & Burnett, 1985). We all remember information best when we can organize it into personally meaningful arrangements. Figure 31.8 An example of chunking—for those who read Chinese After looking at these characters, can you reproduce them exactly? If so, you can read Chinese. MNEMONICS To help encode lengthy passages and speeches, ancient Greek scholars and orators developed mnemonics. Many of these memory aids use vivid imagery, because we are particularly good at remembering mental pictures. We more easily remember concrete, visualizable words than we do abstract words (Akpinar & Berger, 2015). (Try this on a friend or family member: Tell them that in another few minutes you will invite them to recall these words—bicycle, void, cigarette, inherent, fire, process. Is their recall better for the three visualizable words—bicycle, 899 cigarette, and fire?) If you still recall the rock-throwing rioter sentence, it is probably not only because of the meaning you encoded but also because the sentence painted a mental image. mnemonics [nih-MON-iks] memory aids, especially those techniques that use vivid imagery and organizational devices. The peg-word system harnesses our superior visual-imagery skill. This mnemonic requires you to memorize a jingle: “One is a bun; two is a shoe; three is a tree; four is a door; five is a hive; six is sticks; seven is heaven; eight is a gate; nine is swine; ten is a hen.” Without much effort, you will soon be able to count by peg-words instead of numbers: bun, shoe, tree... and then to visually associate the peg-words with to-be-remembered items. Now you are ready to challenge anyone to give you a grocery list to remember. Carrots? Stick them into the imaginary bun. Milk? Fill the shoe with it. Paper towels? Drape them over the tree branch. Think bun, shoe, tree and you see their associated images: carrots, milk, paper towels. With few errors, you will be able to recall the items in any order and to name any given item (Bugelski et al., 1968). Memory whizzes understand the power of such systems. Star performers in the World Memory Championships do not usually have exceptional intelligence, but rather are superior at using mnemonic strategies (Maguire et al., 2003b). Frustrated by his ordinary memory, science writer Joshua Foer wanted to see how much he could improve it. After a year of intense practice, he won the U.S. Memory Championship by memorizing a pack of 52 playing cards in under two minutes. How did Foer do it? He added vivid new details to memories of a familiar place— his childhood home. Each card, presented in any order, could then match up with the clear picture in his head. As the test subject of his own wild memory experiment, he learned that “you don’t have to be memorizing packs of playing cards to benefit from a little bit of insight into how your 900 mind works” (Foer, 2011a,b). When combined, chunking and mnemonic techniques can be great memory aids for unfamiliar material. Want to remember the colors of the rainbow in order of wavelength? Think of the mnemonic ROY G. BIV (red, orange, yellow, green, blue, indigo, violet). Need to recall the names of North America’s five Great Lakes? Just remember HOMES (Huron, Ontario, Michigan, Erie, Superior). In each case, we chunk information into a more familiar form by creating a word (called an acronym) from the first letters of the to-be-remembered items. HIERARCHIES When people develop expertise in an area, they process information not only in chunks but also in hierarchies composed of a few broad concepts divided and subdivided into narrower concepts and facts. (Figure 32.4 ahead provides a hierarchy of our automatic and effortful memory processing systems.) Organizing knowledge in hierarchies helps us retrieve information efficiently, as Gordon Bower and his colleagues (1969) demonstrated by presenting words either randomly or grouped into categories. When the words were grouped, recall was two to three times better. Such results show the benefits of organizing what you study—of giving special attention to the Module Learning Targets, headings, and Ask Yourself and Test Yourself questions. Taking class and text notes in outline form—a type of hierarchical organization—may also prove helpful (Figure 31.9). Figure 31.9 Hierarchies aid retrieval When we organize words or concepts into hierarchical groups, as 901  illustrated here with some of the concepts from this section, we remember them better than when we see them presented randomly. Distributed Practice We retain information better when our encoding is distributed over time. Experiments have consistently revealed the benefits of this spacing effect (Cepeda et al., 2006; Soderstrom et al., 2016). Massed practice (cramming) can produce speedy short-term learning and a feeling of confidence. But to paraphrase Ebbinghaus (1885), those who learn quickly also forget quickly. Distributed practice produces better long-term recall. After you’ve studied long enough to master the material, further study at that time becomes inefficient. Better to spend that extra reviewing time later—a day later if you need to remember something 10 days hence, or a month later if you need to remember something 6 months hence (Cepeda et al., 2008). The spacing effect is one of psychology’s most reliable findings, and it extends to motor skills and online game performance, too (Stafford & Dewar, 2014). Memory researcher Henry Roediger (2013) sums it up: “Hundreds of studies have shown that distributed practice leads to more durable learning.” spacing effect the tendency for distributed study or practice to yield better long-term retention than is achieved through massed study or practice. “ The mind is slow in unlearning what it has been long in learning.” Roman philosopher Seneca (4 B.C.E.–65 C.E.) One effective way to distribute practice is repeated self-testing, a phenomenon that researchers Roediger and Jeffrey Karpicke (2006) have called the testing effect. Testing does more than assess learning and memory: It improves them (Brown et al., 2014; Pan et al., 2015; Trumbo et al., 2016). In this text, the testing questions interspersed throughout and 902 at the end of each module and unit offer opportunities to improve learning and memory. Better to practice retrieval (as any exam will demand) than to merely reread material (which may lull you into a false sense of mastery). Roediger (2013) explains, “Two techniques that students frequently report using for studying—highlighting (or underlining) text and rereading text— [have been found] ineffective.” Happily, “retrieval practice (or testing) is a powerful and general strategy for learning.” As another memory expert explained, “What we recall becomes more recallable” (Bjork, 2011). No wonder daily quizzing improves psychology students’ course performance (Batsell et al., 2017; Pennebaker et al., 2013). AP® EXAM TIP It’s not the studying you do in May that will determine your success on the AP® exam; it’s the studying you do now. It’s a good idea to take a little time each week to quickly review material from earlier in the course. When was the last time you looked at information from the previous units? testing effect enhanced memory after retrieving, rather than simply rereading, information. Also sometimes referred to as a retrieval practice effect or test-enhanced learning. The point to remember: Spaced study and self-assessment beat cramming and rereading. Practice may not make perfect, but smart practice —occasional rehearsal with self-testing—makes for lasting memories. 903  Check Your Understanding Ask Yourself Does it surprise you to learn how much of your memory processing is automatic? What might life be like if all memory processing were effortful? Test Yourself What is the difference between automatic and effortful processing, and what are some examples of each? At which of Atkinson-Shiffrin’s three memory stages would iconic and echoic memory occur? Answers to the Test Yourself questions can be found in Appendix E at the end of the book. Levels of Processing 31-8 What are the levels of processing, and how do they affect encoding? Memory researchers have discovered that we process verbal information at different levels, and that depth of processing affects our long-term retention. Shallow processing encodes on an elementary level, such as a word’s letters or, at a more intermediate level, a word’s sound. Thus we may type there when we mean their, write when we mean right, and two when we mean too. Deep processing encodes semantically, based on the meaning of the words. The deeper (more meaningful) the processing, the better our retention. 904  shallow processing encoding on a basic level, based on the structure or appearance of words. deep processing encoding semantically, based on the meaning of the words; tends to yield the best retention. In one classic experiment, researchers Fergus Craik and Endel Tulving (1975) flashed words at viewers. Then they asked them questions that would elicit different levels of processing. To experience the task yourself, rapidly answer the following sample questions: TABLE 31.1 Sample Questions to Elicit Different Levels of Processing Word Sample Questions Flashed Yes No Most shallow: Is the word in capital CHAIR _______ _______ letters? Shallow: Does the word rhyme with brain _______ _______ train? Deep: Would the word fit in this doll _______ _______ sentence? The girl put the _______ on the table. Which type of processing would best prepare you to recognize the words at a later time? In Craik and Tulving’s experiment, the deeper, semantic processing triggered by the third question yielded a much better memory than did the shallower processing elicited by the second question or the very shallow processing elicited by the first question (which was especially ineffective). Making Material Personally Meaningful If new information is neither meaningful nor related to our experience, we have trouble processing it. Imagine being asked to remember the following 905 recorded passage: The procedure is actually quite simple. First you arrange things into different groups. Of course, one pile may be sufficient depending on how much there is to do.... After the procedure is completed, one arranges the materials into different groups again. Then they can be put into their appropriate places. Eventually they will be used once more and the whole cycle will then have to be repeated. However, that is part of life. When some students heard the paragraph you have just read, without a meaningful context, they remembered little of it (Bransford & Johnson, 1972). When others were told the paragraph described washing clothes (something meaningful), they remembered much more of it—as you probably could now after rereading it. AP® EXAM TIP Are you often pressed for time? The most effective way to cut down on the amount of time you need to spend studying is to increase the personal meaningfulness of the material you’re trying to remember. If you can relate the material to your own life—and that’s pretty easy when you’re studying psychology—it takes less time to master it. Can you repeat the sentence about the rioter that we gave you at this module’s beginning (“The angry rioter threw...”)? Perhaps, like those in an experiment by William Brewer (1977), you recalled the sentence by the meaning you encoded when you read it (for example, “The angry rioter threw the rock through the window”) and not as it was written (“The angry rioter threw the rock at the window”). Referring to such mental mismatches, some researchers have likened our minds to theater directors who, given a raw script, imagine the finished stage production (Bower & Morrow, 1990). Asked later what we heard or read, we recall not the literal text but what we encoded. Thus, studying for a test, you may remember 906 your class notes rather than the class itself. TRY THIS Here is another sentence we will ask you about later (in Module 33): “The fish attacked the swimmer.” We can avoid some of these mismatches by rephrasing what we see and hear into meaningful terms. From his experiments on himself, Ebbinghaus estimated that, compared with learning nonsense material, learning meaningful material required one-tenth the effort. As memory researcher Wayne Wickelgren (1977, p. 346) noted, “The time you spend thinking about material you are reading and relating it to previously stored material is about the most useful thing you can do in learning any new subject matter.” Psychologist-actor team Helga Noice and Tony Noice (2006) have described how actors inject meaning into the daunting task of learning “all those lines.” They do it by first coming to understand the flow of meaning: “One actor divided a half-page of dialogue into three [intentions]: ‘to flatter,’ ‘to draw him out,’ and ‘to allay his fears.’” With this meaningful sequence in mind, the actor more easily remembers the lines. Most people excel at remembering personally relevant information. Asked how well certain adjectives describe someone else, we often forget them; asked how well the adjectives describe us, we often remember them. This tendency, called the self-reference effect, is especially strong in members of individualist Western cultures (Symons & Johnson, 1997; Wagar & Cohen, 2003). In contrast, members of collectivist Eastern cultures tend to remember self-relevant and family-relevant information equally well (Sparks et al., 2016). Knowing this, you can understand why some people retain information deemed “relevant to me,” whereas others also remember information relevant to “my family.” The point to remember: The amount remembered depends both on the time spent learning and on your making it meaningful for deep processing. 907  Check Your Understanding Ask Yourself Can you think of three ways to employ the principles in this section to improve your own learning and retention of important ideas? Test Yourself What would be the most effective strategy to learn and retain a list of names of key historical figures for a week? For a year? If you try to make the material you are learning personally meaningful, are you processing at a shallow or a deep level? Which level leads to greater retention? Answers to the Test Yourself questions can be found in Appendix E at the end of the book. 908 Module 31 REVIEW 31-1 What is memory, and how is it measured? Memory is learning that has persisted over time, through the storage and retrieval of information. Evidence of memory may be seen in an ability to recall information, recognize it, or relearn it more easily on a later attempt. 31-2 How do psychologists describe the human memory system? Psychologists use memory models to think and communicate about memory. Information-processing models involve three processes: encoding, storage, and retrieval. Through parallel processing, the human brain processes many things simultaneously. The connectionism information-processing model views memories as products of interconnected neural networks. The three processing stages in the Atkinson-Shiffrin model are sensory memory, short-term memory, and long-term memory. More recent research has updated this model to include two important concepts: (1) working memory, to stress the active processing occurring in the second memory stage; and (2) automatic processing, to address the processing of information outside of conscious awareness. 31-3 How do explicit and implicit memories differ? Explicit (declarative) memories—our conscious memories of facts and experiences—develop with effortful processing, which requires conscious effort and attention. Implicit (nondeclarative) memories—of skills and classically 909 conditioned associations—happen without our awareness, through automatic processing. 31-4 What information do we process automatically? In addition to skills and classically conditioned associations, we automatically process incidental information about space, time, and frequency. 31-5 How does sensory memory work? Sensory memory feeds some information into working memory for active processing there. An iconic memory is a very brief (a few tenths of a second) sensory memory of visual stimuli; an echoic memory is a three- or four-second sensory memory of auditory stimuli. 31-6 What is our short-term and working memory capacity? Short-term memory capacity is about seven items, plus or minus two, but this information disappears from memory quickly without rehearsal. Working memory capacity varies, depending on age, intelligence level, and other factors. 31-7 What are some effortful processing strategies that can help us remember new information? Effective effortful processing strategies include chunking, mnemonics, hierarchies, and distributed practice sessions (which produce results due to the spacing effect). The testing effect is the finding that consciously retrieving, rather than simply rereading, information enhances memory. 31-8 What are the levels of processing, and how do they affect 910  encoding? Depth of processing affects long-term retention. In shallow processing, we encode words based on their structure, appearance, or sound. Retention is best when we use deep processing, encoding words based on their meaning. We also more easily remember material that is personally meaningful— the self-reference effect. Multiple-Choice Questions 1. Caitlin, a fifth grader, is asked to remember her second-grade teacher’s name. What measure of retention will Caitlin use to answer this question? a. Storage b. Recognition c. Relearning d. Recall e. Encoding 2. In history class, James is effortfully connecting the new material to what he has learned in the past. This making of connections in the moment best describes James’ a. iconic memory. b. sensory memory. c. working memory. d. echoic memory. e. long-term memory. 3. Meloni’s new friend from another state just gave her his phone number. As she goes to enter the number into her contacts list she finds that she cannot remember all the numbers in their right order. Which of the following is the best explanation for this failure? 911  a. Being 10 digits long, the number is beyond Miller’s “magic number.” b. She was so excited that she could not type the numbers fast enough. c. She lacks photographic memory. d. Because the number was so short, she did not pay enough attention to it. e. Her iconic memory disrupted her encoding of the number. 4. Which of the following is most likely to be encoded automatically? a. The side-angle-side geometry theorem b. The names of the last 10 U.S. presidents c. What you ate for breakfast this morning d. The names of your cousins e. The license plate of your new car 5. Which of the following is most likely to lead to semantic encoding of a list of words? a. Thinking about how the words relate to your own life b. Practicing the words for a single extended period c. Breaking up the practice into several relatively short sessions d. Noticing where in a sentence the words appear e. Focusing on the number of vowels and consonants in the words Practice FRQs 1. To remember something, we must get information into our brain, retain the information, and later get the information back out. Use the correct terms for these three steps of the process, and explain how this system would apply if you needed to learn the name of a new student who just enrolled in your school today. Answer 1 point: Encoding is the process of getting the new student’s name into your brain. Page 329 912  1 point: Storage is keeping that name in your memory. Page 329 1 point: Retrieval is the process of using that name when greeting the new student later. Page 329 2. Last evening, Carlos’ mom told him he needed to buy milk today. So, he hopped on his bicycle this morning and headed to the corner store to pick up a gallon. Explain how both implicit and explicit memories were involved in Carlos’ errand. (4 points) 913 Module 32 Storing and Retrieving Memories LEARNING TARGETS 32-1 Discuss the capacity of and location of our long-term memories. 32-2 Describe the roles of the frontal lobes and hippocampus in memory processing. 32-3 Describe the roles of the cerebellum and basal ganglia in memory processing. 32-4 Discuss how emotions affect our memory processing. 32-5 Explain how changes at the synapse level affect our memory processing. 32-6 Analyze how external cues, internal emotions, and order of appearance influence memory retrieval. 914 Memory Storage 32-1 What is the capacity of long-term memory? Are our long- term memories processed and stored in specific locations? In Arthur Conan Doyle’s A Study in Scarlet, Sherlock Holmes offers a popular theory of memory capacity: I consider that a man’s brain originally is like a little empty attic, and you have to stock it with such furniture as you choose.... It is a mistake to think that that little room has elastic walls and can distend to any extent. Depend upon it, there comes a time when for every addition of knowledge you forget something that you knew before. Contrary to Holmes’ “memory model,” our brain is not like an attic, which once filled can store more items only if we discard old ones. Our capacity for storing long-term memories is essentially limitless. One research team, after studying the brain’s neural connections, estimated its storage capacity as “in the same ballpark as the World Wide Web” (Sejnowski, 2016). Retaining Information in the Brain I [DM] marveled at my aging mother-in-law, a retired pianist and organist. At age 88, her blind eyes could no longer read music. But let her sit at a keyboard and she would flawlessly play any of hundreds of hymns, including ones she had not thought of for 20 years. Where did her brain store those thousands of sequenced notes? For a time, some surgeons and memory researchers marveled at patients’ apparently vivid memories triggered by brain stimulation during surgery. Did this prove that our whole past, not just well-practiced music, is “in there,” in complete detail, just waiting to be relived? On closer analysis, the seeming flashbacks appeared to have been invented, not a vivid reliving of long-forgotten experiences (Loftus & Loftus, 1980). In a 915 further demonstration that memories do not reside in single, specific spots, psychologist Karl Lashley (1950) trained rats to find their way out of a maze, then surgically removed pieces of their brain’s cortex and retested their memory. No matter which small brain section he removed, the rats retained at least a partial memory of how to navigate the maze. Memories are brain-based, but the brain distributes the components of a memory across a network of locations. These specific locations include some of the circuitry involved in the original experience: Some brain cells that fire when we experience something fire again when we recall it (Miller, 2012a; Miller et al., 2013). “ Our memories are flexible and superimposable, a panoramic blackboard with an endless supply of chalk and erasers.” Elizabeth Loftus and Katherine Ketcham, The Myth of Repressed Memory, 1994 The point to remember: Despite the brain’s vast storage capacity, we do not store information as libraries store their books, in single, precise locations. Instead, brain networks encode, store, and retrieve the information that forms our complex memories. Explicit Memory System: The Frontal Lobes and Hippocampus 32-2 What roles do the frontal lobes and hippocampus play in memory processing? Explicit, conscious memories are either semantic (facts and general knowledge) or episodic (experienced events). The network that processes and stores new explicit memories for these facts and episodes includes your frontal lobes and hippocampus. When you summon up a mental encore of a past experience, many brain regions send input to your prefrontal cortex (the front part of your frontal lobes) for working memory processing (de Chastelaine et al., 2016; Michalka et al., 2015). The left and right frontal lobes process different types of memories. Recalling a password and holding it in working memory, for example, would activate 916 the left frontal lobe. Calling up a visual party scene would more likely activate the right frontal lobe. semantic memory explicit memory of facts and general knowledge; one of our two conscious memory systems (the other is episodic memory). episodic memory explicit memory of personally experienced events; one of our two conscious memory systems (the other is semantic memory). Cognitive neuroscientists have found that the hippocampus, a temporal-lobe neural center located in the limbic system, can be likened to a “save” button for explicit memories (Figure 32.1). Brain scans reveal activity in the hippocampus and nearby brain networks as people form explicit memories of names, images, and events (Squire & Wixted, 2011; Wang et al., 2014). hippocampus a neural center located in the limbic system; helps process explicit (conscious) memories—of facts and events—for storage. Figure 32.1 The hippocampus 917  Explicit memories for facts and episodes are processed in the hippocampus (orange structures) and fed to other brain regions for storage. Damage to this structure therefore disrupts the formation and recall of explicit memories. If their hippocampus is severed, chickadees and other birds will continue to cache food in hundreds of places, but later be unable to find them (Kamil & Cheng, 2001; Sherry & Vaccarino, 1989). With left-hippocampus damage, people have trouble remembering verbal information, but they have no trouble recalling visual designs and locations. With right-hippocampus damage, the problem is reversed (Schacter, 1996). Subregions of the hippocampus also serve different functions. One part is active as people and mice learn social information (Okuyama et al., 2016; Zeineh et al., 2003). Another part is active as memory champions engage in spatial mnemonics (Maguire et al., 2003a). The rear area, which processes spatial memory, grows bigger as London cabbies navigate the city’s complicated maze of streets (Woolett & Maguire, 2011). Memories are not permanently stored in the hippocampus. Instead, this structure seems to act as a loading dock where the brain registers and temporarily holds the elements of a to-be-remembered episode—its smell, feel, sound, and location. Then, like older files shifted to a basement storeroom, memories migrate for storage elsewhere. This storage process is called memory consolidation. Removing a rat’s hippocampus 3 hours after it learns the location of some tasty new food disrupts this process and prevents long-term memory formation; removal 48 hours later does not (Tse et al., 2007). memory consolidation the neural storage of a long-term memory. Sleep supports memory consolidation. In one experiment, students who 918 learned material in a study/sleep/restudy condition remembered material better both a week and six months later than those who studied in the morning and restudied in the evening without intervening sleep (Mazza et al., 2016). During deep sleep, the hippocampus processes memories for later retrieval. After a training experience, the greater one’s heart rate efficiency and hippocampus activity during sleep, the better the next day’s memory will be (Peigneux et al., 2004; Whitehurst et al., 2016). Researchers have watched the hippocampus and brain cortex displaying simultaneous activity rhythms during sleep, as if they were having a dialogue (Euston et al., 2007; Mehta, 2007). They suspect that the brain is replaying the day’s experiences as it transfers them to the cortex for long- term storage (Squire & Zola-Morgan, 1991). When our learning is distributed over days rather than crammed into a single day, we experience more sleep-induced memory consolidation. And that helps explain the spacing effect. Hippocampus hero Among animals, one contender for champion memorist would be a mere birdbrain—the Clark’s Nutcracker—which during winter and spring can locate up to 6000 caches of pine seed it had previously buried (Shettleworth, 1993). Implicit Memory System: The Cerebellum and Basal Ganglia 32-3 What roles do the cerebellum and basal ganglia play in memory processing? 919 Your hippocampus and frontal lobes are processing sites for your explicit memories. But you could lose those areas and still, thanks to automatic processing, lay down implicit memories for skills and newly conditioned associations. Joseph LeDoux (1996) recounted the story of a brain- damaged patient whose amnesia left her unable to recognize her physician as, each day, he shook her hand and introduced himself. One day, she yanked her hand back, for the physician had pricked her with a tack in his palm. The next time he returned to introduce himself she refused to shake his hand but couldn’t explain why. Having been classically conditioned, she just wouldn’t do it. Implicitly, she felt what she could not explain. The cerebellum plays a key role in forming and storing the implicit memories created by classical conditioning. With a damaged cerebellum, people cannot develop certain conditioned reflexes, such as associating a tone with an impending puff of air—and thus do not blink in anticipation of the puff (Daum & Schugens, 1996; Green & Woodruff-Pak, 2000). Implicit memory formation needs the cerebellum. The basal ganglia, deep brain structures involved in motor movement, facilitate formation of our procedural memories for skills (Mishkin, 1982; Mishkin et al., 1997). The basal ganglia receive input from the cortex but do not return the favor of sending information back to the cortex for conscious awareness of procedural learning. If you have learned how to 920 ride a bike, thank your basal ganglia. Our implicit memory system, enabled by these more ancient brain areas, helps explain why the reactions and skills we learned during infancy reach far into our future. Yet as adults, our conscious memory of our first four years is largely blank, an experience called infantile amnesia. In one study, events children experienced and discussed with their mothers at age 3 were 60 percent remembered at age 7 but only 34 percent remembered at age 9 (Bauer et al., 2007). Two influences contribute to infantile amnesia: First, we index much of our explicit memory with a command of language that young children do not possess. Second, the hippocampus is one of the last brain structures to mature, and as it does, more gets retained (Akers et al., 2014). The Amygdala, Emotions, and Memory 32-4 How do emotions affect our memory processing? Our emotions trigger stress hormones that influence memory formation. When we are excited or stressed, these hormones make more glucose energy available to fuel brain activity, signaling the brain that something important is happening. Moreover, stress hormones focus memory. Stress provokes the amygdala (two limbic system, emotion-processing clusters) to initiate a memory trace that boosts activity in the brain’s memory- forming areas (Buchanan, 2007; Kensinger, 2007) (Figure 32.2). It’s as if the amygdala says, “Brain, encode this moment for future reference!” The result? Emotional arousal can sear certain events into the brain, while disrupting memory for irrelevant events (Brewin et al., 2007; McGaugh, 2015). 921  Figure 32.2 Review key memory structures in the brain Frontal lobes and hippocampus: explicit memory formation Cerebellum and basal ganglia: implicit memory formation Amygdala: emotion-related memory formation Significantly stressful events can form almost unforgettable memories. After a traumatic experience—a school shooting, a house fire, a rape— vivid recollections of the horrific event may intrude again and again. It is as if they were burned in: “Stronger emotional experiences make for stronger, more reliable memories,” noted James McGaugh (1994, 2003). Such experiences even strengthen recall for relevant, immediately preceding events (Dunsmoor et al., 2015: Jobson & Cheraghi, 2016). This makes adaptive sense: Memory serves to predict the future and to alert us to potential dangers. Emotional events produce tunnel vision memory. They focus our attention and recall on high priority information, and reduce our recall of irrelevant details (Mather & Sutherland, 2012). Whatever rivets our attention gets well recalled, at the expense of the surrounding context. Emotion-triggered hormonal changes help explain why we long remember exciting or shocking events, such as our first kiss or our whereabouts when learning of a loved one’s death. In a 2006 Pew survey, 95 percent of American adults said they could recall exactly where they were or what they were doing when they first heard the news of the 9/11 terrorist attacks. This perceived clarity of memories of surprising, 922 significant events (where were you when learning that Donald Trump was elected U.S. president?) leads some psychologists to call them flashbulb memories. flashbulb memory a clear, sustained memory of an emotionally significant moment or event. The people who experienced a 1989 San Francisco earthquake had perfect recall, a year and a half later, of where they had been and what they were doing (verified by their recorded thoughts within a day or two of the quake). Others’ memories for the circumstances under which they merely heard about the quake were more prone to errors (Neisser et al., 1991; Palmer et al., 1991). Our flashbulb memories are noteworthy for their vividness and our confidence in them. But as we relive, rehearse, and discuss them, even these memories may come to err. With time, some errors crept into people’s 9/11 recollections (compared with their earlier reports taken right after 9/11). Mostly, however, people’s memories of 9/11 remained consistent over the next two to three years (Conway et al., 2009; Hirst et al., 2009). Dramatic experiences remain clear in our memory in part because we rehearse them (Hirst & Phelps, 2016). We think about them and describe them to others. Memories of our best experiences, which we enjoy recalling and recounting, also endure (Storm & Jobe, 2012; Talarico & Moore, 2012). One study invited 1563 Boston Red Sox and New York Yankees fans to recall the baseball championship games between their two teams in 2003 (Yankees won) and 2004 (Red Sox won). Fans recalled much better the game their team won (Breslin & Safer, 2011). FYI Which is more important—your experiences or your memories of them? 923 Synaptic Changes 32-5 How do changes at the synapse level affect our memory processing? As you read this module and think and learn about memory processes, your brain is changing. Given increased activity in particular pathways, neural interconnections are forming and strengthening. The quest to understand the physical basis of memory—how information becomes embedded in brain matter—has sparked study of the synaptic meeting places where neurons communicate with one another via their neurotransmitter messengers. Eric Kandel and James Schwartz (1982) observed synaptic changes during learning in the neurons of the California sea slug, Aplysia, a simple animal with a mere 20,000 or so unusually large and accessible nerve cells. Module 26 noted how the sea slug can be classically conditioned (with electric shock) to reflexively withdraw its gills when squirted with water, much as a soldier traumatized by combat might jump at the sound of a firecracker. When learning occurs, Kandel and Schwartz discovered, the slug releases more of the neurotransmitter serotonin into certain neurons. These cells’ synapses then become more efficient at transmitting signals. Experience and learning can increase—even double—the number of synapses, even in slugs (Kandel, 2012). Aplysia The California sea slug, which neuroscientist Eric Kandel studied for 45 years, has increased our understanding of the neural basis of learning and memory. In experiments with people, rapidly stimulating certain memory-circuit 924 connections has increased their sensitivity for hours or even weeks to come. The sending neuron now needs less prompting to release its neurotransmitter, and more connections exist between neurons. This increased efficiency of potential neural firing, called long-term potentiation (LTP), provides a neural basis for learning and remembering associations (Lynch, 2002; Whitlock et al., 2006) (Figure 32.3). Several lines of evidence confirm that LTP is a physical basis for memory: Drugs that block LTP interfere with learning (Lynch & Staubli, 1991). Drugs that mimic what happens during learning increase LTP (Harward et al., 2016). Rats given a drug that enhanced LTP learned a maze with half the usual number of mistakes (Service, 1994). long-term potentiation (LTP) an increase in a cell’s firing potential after brief, rapid stimulation; a neural basis for learning and memory. Figure 32.3 Doubled receptor sites An electron microscope image (a) shows just one receptor site (gray) reaching toward a sending neuron before long-term potentiation. Image (b) shows that, after LTP, the receptor sites have doubled. This means the receiving neuron has increased sensitivity for detecting the presence of the neurotransmitter molecules that may be 925  released by the sending neuron (Toni et al., 1999). Flip It Video: Long-Term Potentiation After LTP has occurred, passing an electric current through the brain won’t disrupt old memories. But the current will wipe out very recent memories. Such is the experience both of laboratory animals and of severely depressed people given electroconvulsive therapy (ECT) (see Module 73). A blow to the head can do the same. Football players and boxers momentarily knocked unconscious typically have no memory of events just before the knockout (Yarnell & Lynch, 1970). Their working memory had no time to consolidate the information into long-term memory before the lights went out. Recently, I [DM] did a little test of memory consolidation. While on an operating table for a basketball-related tendon repair, I was given a face mask and soon could smell the anesthesia gas. “So how much longer will I be with you?” I asked the anesthesiologist. My last moment of memory was her answer: “About 10 seconds.” My brain spent that 10 seconds consolidating a memory for her 2-second answer, but could not tuck any further memory away before I was out cold. Some memory-biology explorers have helped found companies that are competing to develop memory-altering drugs. The target market for memory-boosting drugs includes millions of people with Alzheimer’s disease, millions more with mild cognitive impairment that often becomes Alzheimer’s, and countless millions who would love to turn back the clock on age-related memory decline. Meanwhile, one safe and free memory enhancer is already available for high schoolers everywhere: study followed by adequate sleep! (You’ll find study tips in Module 2 and at the end of this module, and sleep coverage in Modules 23 and 24.) One approach to improving memory focuses on drugs that boost the LTP-enhancing neurotransmitter glutamate (Lynch et al., 2011). Another approach involves developing drugs that boost production of CREB, a protein that also enhances the LTP process (Fields, 2005). Boosting CREB production might trigger increased production of other proteins that help 926 reshape synapses and transfer short-term memories into long-term memories. Some of us may wish for memory-blocking drugs that, when taken after a traumatic experience, might blunt intrusive memories (Adler, 2012; Kearns et al., 2012). In one experiment, victims of car accidents, rapes, and other traumas received, for 10 days following their horrific event, either one such drug, propranolol, or a placebo. When tested three months later, half the placebo group but none of the drug-treated group showed signs of stress (Pitman & Delahanty, 2005; Pitman et al., 2002). Figure 32.4 summarizes the brain’s two-track memory processing and storage system for implicit (automatic) and explicit (effortful) memories. The bottom line: Learn something and you change your brain a little. Figure 32.4 Our two memory systems AP® EXAM TIP Figure 32.4 is an excellent summary. Why don’t you review it for a few minutes and then see how much of it you can reproduce on a piece of paper? That will give you a good assessment of which parts of the memory process you know 927 and which parts you still need to work on. Check Your Understanding Ask Yourself Can you name an instance in which stress has helped you remember something, and another instance in which stress has interfered with remembering something? Test Yourself Which parts of the brain are important for implicit memory processing, and which parts play a key role in explicit memory processing? Your friend has experienced brain damage in an accident. He can remember how to tie his shoes but has a hard time remembering anything you tell him during a conversation. How can implicit versus explicit information processing explain what’s going on here? Which brain area responds to stress hormones by helping to create stronger memories? Increased efficiency at the synapses is evidence of the neural basis of learning and memory. This is called ______________-______________ ______________. Answers to the Test Yourself questions can be found in Appendix E at the end of the book. 928 Memory Retrieval Flip It Video: Improving Retrieval After the magic of brain encoding and storage, we still have the daunting task of retrieving the information. What triggers retrieval? Retrieval Cues 32-6 How do external cues, internal emotions, and order of appearance influence memory retrieval? Imagine a spider suspended in the middle of her web, held up by the many strands extending outward from her in all directions to different points. If you were to trace a pathway to the spider, you would first need to create a path from one of these anchor points and then follow the strand down into the web. The process of retrieving a memory follows a similar principle, because memories are held in storage by a web of associations, each piece of information interconnected with others. When you encode into memory a target piece of information, such as the name of the person sitting next to you in class, you associate with it other bits of information about your surroundings, mood, seating position, and so on. These bits can serve as retrieval cues that you can later use to access the information. The more retrieval cues you have, the better your chances of finding a route to the suspended memory. To remember to do something (say, to write a note tomorrow), one effective strategy is to mentally associate the act with a cue (perhaps a pen left in the middle of your desk) (Rogers & Milkman, 2016). “Memory is not like a container that gradually fills up; it is more like a tree growing hooks onto which memories are hung.” Peter Russell, The Brain Book, 1979 The best retrieval cues come from associations we form at the time we 929 encode a memory—smells, tastes, and sights that can evoke our memory of the associated person or event. To call up visual cues when trying to recall something, we may mentally place ourselves in the original context. After losing his sight, British scholar John Hull (1990, p. 174) described his difficulty recalling such details: I knew I had been somewhere, and had done particular things with certain people, but where? I could not put the conversations... into a context. There was no background, no features against which to identify the place. Normally, the memories of people you have spoken to during the day are stored in frames which include the background. Priming Often our associations are activated without our awareness. Philosopher- psychologist William James referred to this process, which we call priming, as the “wakening of associations.” After seeing or hearing the word rabbit, we are later more likely to spell the spoken word hair/hare as h-a-r-e, even if we don’t recall seeing or hearing rabbit (Figure 32.5). priming the activation, often unconsciously, of particular associations in memory. 930  Figure 32.5 Priming associations unconsciously activates related associations (Bower, 1986). Priming is often “memoryless memory”—an implicit, invisible memory, without your conscious awareness. If, walking down a hallway, you see a poster of a missing child, you may then unconsciously be primed to interpret an ambiguous adult-child interaction as a possible kidnapping (James, 1986). Although you no longer have the poster in mind, it predisposes your interpretation. Meeting someone who reminds us of a person we’ve previously met can awaken our associated feelings about that earlier person, which may transfer into the new context (Andersen & Saribay, 2005; Lewicki, 1985). Priming can influence behaviors as well (Herring et al., 2013). Adults and children primed with money-related words and materials were less likely to help another person when asked (Gasiorowska et al., 2016; Vohs et al., 2006). In such cases, money may prime our materialism and self- interest rather than the social norms that encourage us to help (Ariely, 2009). Context-Dependent Memory Have you noticed? Putting yourself back in the context where you earlier experienced something can prime your memory retrieval. Remembering, in many ways, depends on our environment (Palmer, 1989). When you visit your childhood home or neighborhood, old memories surface. As Figure 32.6 illustrates, when scuba divers listened to a word list in two different settings (either 10 feet underwater or sitting on the beach), they recalled more words if tested in the same place (Godden & Baddeley, 1975). 931  Figure 32.6 The effects of context on memory In this experiment, words heard underwater were best recalled underwater. Words heard on land were best recalled on land (Godden & Baddeley, 1975). By contrast, experiencing something outside the usual setting can be confusing. Have you ever run into a former teacher in an unusual place, such as at the store or park? Perhaps you recognized the person but struggled to figure out who it was and how you were acquainted. The encoding specificity principle helps us understand how cues specific to an event or person will most effectively trigger that memory. In new settings, you may not have the memory cues needed for speedy face recognition. Our memories are context-dependent, and are affected by the cues we have associated with that context. Thankfully, overlearning—mastering the material beyond barely knowing it—can nevertheless enable you to do well when taking an AP exam in a new room. encoding specificity principle the idea that cues and contexts specific to a particular memory will be most effective in helping us recall it. 932  TRY THIS Ask a friend two rapid-fire questions: (a) How do you pronounce the word spelled by the letters s-h-o-p? (b) What do you do when you come to a green light? If your friend answers “stop” to the second question, you have demonstrated priming. In several experiments, Carolyn Rovee-Collier (1993) found that a familiar context could activate memories even in 3-month-olds. After infants learned that kicking would make a crib mobile move via a connecting ribbon from their ankle, the infants kicked more when tested again in the same crib than when in a different context. State-Dependent Memory Closely related to context-dependent memory is state-dependent memory. What we learn in one state—be it drunk or sober—may be more easily recalled when we are again in that state. What people learn when drunk they don’t recall well in any state (alcohol disrupts memory storage). But they recall it slightly better when again drunk. Someone who hides money when drunk may forget the location until drunk again. Moods also provide an example of memory’s state dependence. Emotions that accompany good or bad events become retrieval cues (Gaddy & Ingram, 2014). Thus, our memories are somewhat mood congruent. If you’ve had a bad evening—your plans with friends fell through, your favorite jeans have disappeared, your Internet went out 10 minutes before the end of a show—your gloomy mood may facilitate recalling other bad times. Being depressed sours memories by priming negative associations, which we then use to explain our current mood. In many experiments, people put in a buoyant mood—whether under hypnosis or just by the day’s events (a World Cup soccer victory for German participants in one study)—recall the world through rose-colored glasses (DeSteno et al., 2000; Forgas et al., 1984; Schwarz et al., 1987). They recall their behaviors as competent and effective, other people as benevolent, happy events as more frequent. 933  mood-congruent memory the tendency to recall experiences that are consistent with one’s current good or bad mood. Have you ever noticed that your mood influences your perceptions of your parents? In one study, adolescents’ ratings of parental warmth in one week gave little clue to how they would rate their parents six weeks later (Bornstein et al., 1991). When teens were down, their parents seemed cruel; as their mood brightened, their parents morphed from devils into angels. We may nod our heads knowingly. Yet, in a good or bad mood, we persist in attributing to reality our own changing judgments, memories, and interpretations. In a bad mood, we may read someone’s look as a glare and feel even worse. In a good mood, we may encode the same look as interest and feel even better. Moods magnify. “I can’t remember what we’re arguing about, either. Let’s keep yelling, and maybe it will come back to us.” Mood effects on retrieval help explain why our moods persist. When happy, we recall happy events and therefore see the world as a happy place, which helps prolong our good mood. When depressed, we recall sad events, which darkens our interpretations of current events. For those of us predisposed to depression, this process can help maintain a vicious, dark cycle. 934  “ When a feeling was there, they felt as if it would never go; when it was gone, they felt as if it had never been; when it returned, they felt as if it had never gone.” George MacDonald, What’s Mine’s Mine, 1886 Serial Position Effect Another memory-retrieval quirk, the serial position effect, explains why we may have large holes in our memory of a list of recent events. Imagine it’s your first day on a job, and your manager is introducing co-workers. As you meet each person, you silently repeat everyone’s name, starting from the beginning. As the last person smiles and turns away, you feel confident you’ll be able to greet your new co-workers by name the next day. serial position effect our tendency to recall best the last (recency effect) and first (primacy effect) items in a list. Don’t count on it. Because you have spent more time rehearsing the earlier names than the later ones, those are the names you’ll probably recall more easily the next day. In experiments, when people viewed a list of items (words, names, dates, even experienced odors) and immediately tried to recall them in any order, they fell prey to the serial position effect (Reed, 2000). They briefly recalled the last items especially quickly and well (a recency effect), perhaps because those last items were still in working memory. But after a delay, when their attention was elsewhere, their recall was best for the first items (a primacy effect; see Figure 32.7). 935  Figure 32.7 The serial position effect Immediately after Pope Francis made his way through this receiving line of special guests, he would probably have recalled the names of the last few people best (recency effect). But later he may have been able to recall the first few people best (primacy effect). Check Your Understanding Ask Yourself What sort of mood have you been in lately? How has your mood colored your memories, perceptions, and expectations? Test Yourself You have just watched a movie that includes a chocolate factory. After the chocolate factory is out of mind, you nevertheless feel a strange urge for a chocolate bar. How do you explain this in terms of priming? When we are tested immediately after viewing a list of words, we tend to recall the first and last items best, which is known as the ______________ ______________ effect. Answers to the Test Yourself questions can be found in Appendix E at the end of the book. 936 Module 32 REVIEW 32-1 What is the capacity of long-term memory? Are our long- term memories processed and stored in specific locations? Our long-term memory capacity is essentially unlimited. Memories are not stored intact in the brain in single spots. Many parts of the brain interact as we form and retrieve memories. 32-2 What roles do the frontal lobes and hippocampus play in memory processing? The frontal lobes and hippocampus are parts of the brain network dedicated to explicit memory formation. Many brain regions send information to the frontal lobes for processing. The hippocampus, with the help of surrounding areas of cortex, registers and temporarily holds elements of explicit memories before moving them to other brain regions for long-term storage (memory consolidation). 32-3 What roles do the cerebellum and basal ganglia play in memory processing? The cerebellum and basal ganglia are parts of the brain network dedicated to implicit memory formation. The cerebellum is important for storing classically conditioned memories. The basal ganglia are involved in motor movement and help form procedural memories for skills. Many reactions and skills learned during our first four years continue 937  into our adult lives, but we cannot consciously remember learning these associations and skills—a phenomenon psychologists call “infantile amnesia.” 32-4 How do emotions affect our memory processing? Emotional arousal causes an outpouring of stress hormones, which lead to activity in the brain’s memory-forming areas. Significantly emotional events can trigger very clear flashbulb memories. 32-5 How do changes at the synapse level affect our memory processing? Long-term potentiation (LTP) appears to be the neural basis for learning and memory. In LTP, neurons become more efficient at releasing and sensing the presence of neurotransmitters, and more connections develop between neurons. 32-6 How do external cues, internal emotions, and order of appearance influence memory retrieval? External cues activate associations that help us retrieve memories; this process may occur without our awareness, as it does in priming. Returning to the same physical context or emotional state (mood congruency) in which we formed a memory can help us retrieve it. The serial position effect accounts for our tendency to recall best the last items (which may still be in working memory) and the first items (which we’ve spent more time rehearsing) in a list. Multiple-Choice Questions 1. What two parts of the brain are most involved in implicit memory? a. Frontal lobes and basal ganglia b. Amygdala and hippocampus 938