Introduction to Psychological Science: Integrating Behavioral, Neuroscience and Evolutionary Perspectives - William J. Ray 2021

Memory

LEARNING OBJECTIVES

✵ 7.1 Discuss memory and how information is stored and retrieved.

✵ 7.2 Describe how memories are organized and stored in the brain.

✵ 7.3 Describe how people differ in their memory abilities.

✵ 7.4 Discuss the key theories of how we create false memories and misinformation.

In March 1985, an English musician known for his knowledge of choral music of the 17th and 18th centuries reported experiencing a headache. The headache did not go away. Clive Wearing later collapsed and was rushed to a local hospital. It was determined that he had an infection in his brain, herpes encephalitis, which destroyed parts of his brain, including the hippocampus. Although he had no problem speaking or writing English, his memory was disrupted. Clive could recognize his wife and experienced delight at seeing her. However, he could not remember anything that occurred in the present time for longer than a few seconds. That is, within seconds after an event occurred, it was lost to his experience.

In her memoir, Forever Today: A Memoir of Love and Amnesia, his wife Deborah writes,

It was as if every waking moment was the first waking moment. Clive was under the constant impression that he had just emerged from unconsciousness because he had no evidence in his own mind of ever being awake before.… “I haven’t heard anything, seen anything, touched anything, smelled anything,” he would say. “It’s like being dead.”

(Wearing, 2005, p. 202-203)

Clive recorded in his journal in the hospital, “I am conscious for the first time…” and then noted the time. He made a number of such entries on the same day. Every event that Clive experienced was as if it were happening for the first time. Clive Wearing has been described as having the most devastating case of amnesia ever recorded.

(Sacks, 2007)

For more information see:

Sacks, Oliver (2007). The abyss. The New Yorker (24 September).

Wearing, Deborah (2005). Forever Today: A Memoir of Love and Amnesia. New York: Random House.

A Radiolab story told by Oliver Sacks and Clive’s wife is available online (https://www.wnycstudios.org/podcasts/radiolab/segments/91578-clive).

A video presentation of Clive Wearing can be seen in the PBS series The Mind (Episode 1, 1988).

In thinking about Clive Wearing, it becomes apparent that memory is not a unitary process. Although Clive Wearing lost his memory for present events after some seconds, he could still recognize his wife, and speak, read, and understand English. He could also perform tasks such as playing the piano that he had previously learned. Think for a second what your life would be like if you could only remember things for a few seconds. Who would you be? Most of us think of ourselves in terms of experiences we have had in our life and our reactions to these experiences. It is our memories that give us an enduring picture of ourselves.

As you will see in this chapter, there are different types of memory. Where Clive had difficulty was in turning short-term memories into long-term memories that can be retrieved at a later time. In addition to short-term and long-term memory, other types of memory will be introduced in this chapter. These types of memory have to do with particular types of information, but that is getting ahead of our story.

As you will see, when we remember an experience, we actually recreate the experience in our minds. That helps us to understand why we remember the same event slightly differently each time. Depending on the nature of the memory, different parts of the brain can be involved. Some memories have to do with language, some with emotions, some with events, some with sensory experiences, and many with a combination of these.

There is, of course, great value in being able to have access to important parts of your experience and having some aspects be more important than others. From an evolutionary perspective, for instance, organisms that could remember which food was good for them and where it was located survived better than the ones that could not. Remembering and understanding our experiences protects us. Memory is a critical component of our lives.

Two thousand years ago, the Greek dramatist Aeschylus, in Prometheus Bound, said that memory is the mother of all wisdom. Think about what would happen if you lost your memory. Could you learn new things? Could you still ride a bicycle? Could you speak and understand others? Would your world look the same? Would you have a sense of identity? Would you still be you? As you answer these questions you may begin to see the critical role that memory plays in our lives.

Understanding Memory

Learning and memory are processes that go together. Traditionally, learning and memory have focused on different aspects of behavior and experience. In the next chapter, you will read about learning that has traditionally been measured in terms of changes in an individual’s or organism’s behavior based on experience. Historically, psychologists say learning has taken place when behavior changes. Memory traditionally has focused on how this information is stored and later retrieved. The current chapter focuses on memory, whereas the next chapter focuses on learning.

The manner in which you are asked to remember information can also influence your memory ability. For example, when you take a multiple-choice test, you use recognition. That is, if you were asked which of these is the Spanish word for dog and were shown the words “pollo,” “perro,” “gato,” and “cabra” you would only need to recognize that perro is the correct answer. However, if you were asked, “What is the Spanish word for dog?” you would need to recall the information. Essay tests are based on recall. In terms of information, individuals are better able to recognize than recall information.

Before information is stored, it is encoded. That is, certain aspects of your experiences are organized and stored in the brain. Thus, encoding includes how you store information in the brain. Although we use terms such as storing a memory, we now know that remembering an experience is more than just viewing an image of what happened. Memory is a dynamic process that can be changed depending on events (Lee, Nader, & Schiller, 2017). In fact, each time we remember information, our brain reconstructs the event or experience (Vaz, Wittig, Inati, & Zaghloul, 2020). Our brain also helps us to forget things that do not match our behavior and our goals (Anderson & Hulbert, 2021). Unlike a computer that gives you back exactly the information that is stored, our brain has a logic of its own based on our evolutionary history.

How our brains store information was studied in the last century by Wilder Penfield (1891—1976). Penfield was a physician at McGill Hospital in Montreal, Canada, who treated individuals with severe epilepsy. In the 1930s and 1940s, as today, this treatment included brain surgery to help reduce epileptic seizures. In order to protect critical cognitive functions, Penfield wanted to map critical functions in the brain. To do so, he stimulated different parts of the patient’s brain. Since the brain has no pain receptors, these operations were conducted while the patient was conscious. Thus, Penfield would electrically stimulate a specific area of the brain and note the response.

Penfield reported that electrical stimulation to the temporal lobes, and not to other areas of the brain, resulted in the person’s experiencing memories of a previous event or situation. With stimulation, a person might say that he has just had a flashback of his house in childhood or that he remembered a particular family event. One individual reported being at the corner of Jacob and Washington in South Bend, Indiana as a younger person (Penfield, 1952).

Today, in treating epilepsy, it is more common to place an array of electrodes on the person’s cortex. These more recent procedures have also shown that electrical stimulation to the temporal lobe results in the experience of memories (Moriarity, Boatman, Krauss, Storm, & Lenz, 2001; Vignal, Maillard, McGonigal, & Chauvel, 2007). These memories could be recent or from longer ago. Depending on the area of the temporal lobe stimulation, one individual reported experiencing The Flintstones cartoons from childhood, hearing the rock band Pink Floyd, hearing a baseball announcer, or a female voice singing. Noninvasive techniques such as TMS (transcranial magnetic stimulation) are also being used to study memory (Kim, Ekstrom, & Tandon, 2016).

The Temporal Dimension of Memory

Overall, memory is described in terms of two dimensions. The first is the temporal or time dimension. The time dimension includes three domains: sensory memory, short-term memory, and long-term memory. The second dimension utilizes the type of information stored. As you will see, remembering how to ride a bicycle uses a different type of memory than learning information for a test. Let’s first consider the temporal dimension.

Sensory Memory

If you were to listen to someone talk, you would retain the words said for just a few seconds as you processed the next words. This is referred to as sensory memory. Sensory memory lasts only a few seconds and takes place in all of our senses. If it involves the auditory system, it is referred to as echoic memory. If it involves the visual system, it is referred to as iconic memory. This is the first step of how we remember information.

Sensory memory lasts just long enough for the information to be processed by the brain. However, we can’t possibly remember all of the information that is before us in this brief period. In 1859, Sir William Hamilton studied how much information we can process by throwing marbles onto the ground and then trying to instantly determine how many there were. More systematic research was performed by researchers at Bell Laboratories in the 1960s. One of these researchers was George Sperling (Sperling, 1960).

What Sperling did was to allow research participants to view a series of letters for a brief period of time and then asked the participants to repeat them (see Figure 7-2). You can try this yourself by looking at the letters and then quickly putting your hand on top of them. If you do this, you can probably remember a few letters but not more than four or five. They just disappear from your sensory memory. Sperling performed his experiments by presenting the letters for one-twentieth of a second. In another experiment, there were different tones that signaled whether the participant was to report the top row, the middle row, or the bottom row. The tones were presented after the display was no longer available. In this experiment, participants were able to report three of the four letters in the line. What is amazing is that this suggests that, on some level, participants had access to the entire array of letters. However, that access was very short-lived. When Sperling delayed the tone by more than half a second, participants recalled only about half as many letters. Thus, you initially have access to more information than you realize but it is very short-lived.

Figure 7-2 Presentation of letters used by George Sperling.

Short-Term Memory

The second step in remembering information is to transform the sensory information and work with it for a short period of time. This is referred to as short-term memory. As the name implies, short-term memory lasts for less than a minute. The concept of working memory evolved from short-term memory to reflect the systems required to keep things in mind while performing tasks (Baddeley, 2010). That is, working memory is all the information you keep in mind while you pay attention to the task you are doing. If you were ordering a pizza for your friends you might need to remember what toppings your friends liked as you look up the phone number of the pizza parlor. The term “working memory” is somewhat broader than “short-term memory” in that it also refers to your use of attention to influence short-term memory (Cowan, 2008). Both short-term memory and working memory would describe your looking up the number of a pizza place and retaining it briefly as you make the call. Research suggests that verbal short-term memory is stored differently than visual short-term memory in the brain (Schacter & Wagner, 2013).

Overall, short-term memory lasts for about 20 to 30 seconds without rehearsal. If you continue to repeat the phone number, for example, then rehearsal will lengthen the time the information is available to you. If you are not allowed to rehearse the information, then the initial information will be lost in 20 to 30 seconds. This was shown in the 1950s in research by Brown and Peterson (Brown, 1958; Peterson & Peterson, 1959). To ensure that the participants in the study did not rehearse the information presented they were asked to count backwards from a particular number after they were shown three letters that did not form a word. They also varied the amount of time between the presentation of the three letters and when the participants were asked to recall the letters. The shorter the time, the better the letters were remembered.

Overall, short-term memory is active and easy to access, and the contents are remembered in the order presented. However, there is a limit to the number of items that we can remember. Based on a 1956 study by George Miller, it was assumed that the number of items in short-term memory that could be remembered was seven, plus or minus two. That is, if I read you a set of numbers and then asked you to repeat them, most people would be able to repeat approximately seven of them. Some would do better and repeat nine and some people would do worse and repeat five.

It turns out that the limits on short-term memory are not totally straightforward. As you will learn later in the chapter, memory is influenced by many factors. The number of items we can remember may be influenced by how you feel, for instance (Hayes, Hirsch, & Mathews, 2008). It is also associated with how well you score on an intelligence test (Oberauer, Süβ, Wilhelm, & Wittmann, 2008).

Are experts in a particular field able to remember more items? In order to answer this question, William Chase and Herbert Simon (1973) studied chess players who ranged from novice to master players. One question was how experts and novices differ in their approach to chess. Previous research had shown that they did not differ in the number of moves they considered, but the experts were better at choosing the right move. Chase and Simon then asked if the expert chess players differed in their ability to remember the board. In order to study this, they asked the chess players to reproduce where the pieces were located on a chess board from short-term memory.

They discovered that the expert chess players were better able than novices to reproduce the location of pieces in the middle of a game or at the end of a game. The experts did this by chunking the chess pieces into meaningful patterns. That is, they organized the chess pieces into groups. If the pieces were placed randomly on the chess board, the experts did no better than the novices at remembering their location. Thus, it was not the experts’ memory ability that made the difference, but their ability to chunk the material into meaningful groups. With their expertise, the experts could have both more meaningful chunks and a larger number of items in each chunk. In any area of knowledge, if you have more expertise in that area, you can have more items in a single chunk.

Not only do experts use chunking, but we all do it every day. That is, if you place numbers or letters in meaningful groups, you can remember more items. For example, if I asked you to remember these letters—FBIYMCACBSNBCCIA—you may have a difficult time unless you group them. Once you chunk the letters into FBI—YMCA—CBS—NBC—CIA, then remembering 16 letters in five groups becomes easier. Similarly, you tend to chunk phone numbers. Thus, the phone number 9876543210 becomes 987—654—3210, which is easier to remember.

Chunking can take place on both a deliberate and an automatic level (Gobet, Lane, Croker, Cheng, Jones, Oliver, & Pine, 2001). That is, you can purposely chunk a telephone number to help you remember it. With other types of material, chunking is automatic. You will automatically chunk the letters FBIYMCACBSNBCCIA once you see FBI, YMCA, and so forth. In fact, it is hard to group the letters in other ways. This is not unlike the Gestalt perceptual groupings you learned about in the chapter on perception. That is, the visual system also chunks information for efficient processing (Corbett, 2017).

Long-Term Memory

To have a memory available to us in the future, the information needs to be converted from short-term memory into long-term memory. Information available to us through long-term memory can be relatively permanent. Without much trouble, for instance, you can probably remember some of your elementary school teachers and friends, although you may not have seen or thought about them for a long time.

One important contribution to understanding long-term memory was the research related to Henry Molaison (known as H.M. in the research literature), which will be discussed in more detail later in the chapter. Molaison, who had damage to his temporal lobes, could not create long-term memories from short-term ones. Since he could perform short-term memory tasks, it became clear that there are different types of temporal memory and that these types involve different brain areas. It was also discovered that Molaison did possess certain types of long-term memory, such as the ability to increase his skills at specific puzzles. Thus, there are different memory systems. Long-term memory can thus be classified in terms of the type of information that is stored. We now turn to these distinctions.

Types of Long-Term Memory

When asked about the contents of our memory, many of us would think about what has happened to us. We remember being with friends, going to a foreign country, and aspects of our childhood. If you like music, you may remember a particular concert. If you like art, you may remember a particular museum. Sporting events for some people are particularly memorable. That is, we remember events that we have personally experienced. Technically, this type of memory is referred to as episodic memory. Episodic memory is also called autobiographical memory.

The production of episodic memory involves specific areas in the brain. Activity involving the hippocampus has been shown to be a core mechanism underlying episodic memory (Hanslmayr, Staresina, & Bowman, 2016). There are also connections between the hippocampus and the frontal lobe with episodic memory formation (Eichenbaum, 2017). It has also been shown that emotional memories are forgotten more slowly than neutral memories (Yonelinas & Ritchey, 2015). Moreover, it is the amygdala rather than the hippocampus that facilitates these emotional effects.

In addition to events we have personally experienced, we also remember facts. That is, we know information about people, places, and things. Every time you talk with someone about a particular set of facts, you recall information you know. Technically, this is referred to as semantic memory. Semantic memory has to do with impersonal facts and everyday knowledge.

One important characteristic of both episodic and semantic memory is that we can consciously bring forth this information from memory. That is, if someone asks us a question such as, “What is the capital of France?” or “Who was your favorite teacher in high school?”—we remember the answer. Thus, there are similarities between the two memory systems (Renoult, Irish, Moscovitch, & Rugg, 2019). Episodic memory and semantic memory are grouped under the larger heading of explicit memory. Explicit memory is also referred to as declarative memory.

As you will see, some individuals with brain damage can learn how to solve puzzles and develop skills such as tracing a star in a mirror, yet not know he or she had learned these skills. This type of memory is referred to as implicit memory. Implicit memory has the ability to influence our behavior and experiences without our being aware of the learning taking place.

We also can perform a number of motor tasks without consciously remembering how to perform them. You ride a bicycle, drive a car, play a musical instrument, or type a text-message without consciously remembering every step. This type of memory is referred to as procedural memory. Procedural memory is a type of implicit memory.

Implicit memory also includes classical conditioning and priming. Classical conditioning, discussed previously and in more detail in the next chapter, occurs when an unconditioned stimulus is paired with a conditioned stimulus that, in turn, produces the conditioned response. This typically takes place outside of our awareness. For example, one of the physicians working with H.M. placed a tack in his hand so that when H.M. shook hands with him, he would feel a prick. When H.M. saw the group of physicians on a later occasion, as usual, he did not recognize them. However, H.M. was more hesitant to shake hands with one of the physicians—the one who had previously held the tack.

Priming is a situation in which previous experiences can influence present behavior. For example, suppose you were asked to learn a list of words, including absent, income, filly, and discuss. If you were then asked to complete the incomplete word inc___, you would more likely choose income rather than other words beginning with “inc,” such as incomplete, incense, or inchworm, because you had been primed with income. Figure 7-3 presents the different types of long-term memory.

Figure 7-3 Organization of types of long-term memory.

Processes Involved in Learning and Long-Term Explicit Memories

At one time memory was thought to be a literal reproduction of what we experience, as if our brains were simply recorders. In the same way that our vision is not simply a photograph, memory is more than just information pulled out of a computer database. Remembering is a constructive process that allows each recall of information to be a constructive event.

Psychologists have described the long-term memory processes in terms of four separate steps: encoding, storage, consolidation, and retrieval. The first step, encoding, is the process by which information is attended to and connected with other information in memory. Craik and Lockhart (1972) noted that encoding can be “deep” if you pay close attention to the information. However, it can also be shallow, as when you read something and realize later that you cannot remember what you read. Thus, encoding can form a dimension going from deep to shallow.

Much of our encoding in the world is of a shallow nature. This was shown by Raymond Nickerson and Marilyn Adams in a series of studies (1979). In one of these studies, they simply asked participants to draw the face of a penny. This study was performed in a time before people used debit and credit cards for most purchases. Although all Americans at that time used pennies often, few people were able to accomplish this task.

In another study in the series, Nickerson and Adams (1979) asked participants to pick out the correct penny from 15 possibilities. Most college students in the experiment had difficulty picking out the correct penny. Which would you choose from those in Figure 7-4? The authors concluded that frequent exposure to an object does not result in accurate memory of the object.

Figure 7-4 Examples of the top side of the pennies used in the Nickerson and Adam (1979) study. Only one is correct.

For information to be retained in memory, the information must move past the sensory memory stage. A number of factors can influence encoding, including your level of motivation and emotional state. For example, most people only look at pennies to differentiate them from other coins such as nickels or dimes. Our motivation in this case is not to know the image on a penny. In learning information, it is important to do more than just look or read. It is critical to use a deeper structure approach such as considering the different aspects of the material and the manner in which they relate to each other. Overall, the level of encoding is critical for memory retrieval. One practical implication is that if you want to learn information for a class, the more you can connect one type of information with other information in a deep structure manner, the more likely you will be able to remember it on an essay test, for example.

Following encoding, the information must be stored. Storage involves those areas of the brain and neural mechanisms by which memories are retained over time. These mechanisms are different from those of sensory memory and short-term memory. Additionally, the capacity limitations are different. Whereas sensory memory disappears quickly, and short-term memory can contain only a limited amount of information, long-term memory appears almost limitless.

The third step, consolidation, is the process by which the information stored becomes more stable. Consolidation takes place in the brain on two levels (Sandrini, Cohen, & Censor, 2015). The first level involves structural changes at the synapse that take place as noted with the work of Kandel in Chapter 3. The second level involves a reorganization of long-term memories over brain networks. Sleep improves memory consolidation (Genzel, Kroes, Dresler, & Battaglia, 2013; Paller, Creery, & Schechtman, 2021), and lack of sleep interferes with memory consolidation. This has been shown to be true for humans as well as other species. Taking breaks and obtaining sleep will enhance learning of any type including course material.

The fourth step is retrieval. This stage is what we think of when we say we recalled something. Typically, retrieval involves different types of information stored in different places throughout the brain. This information can include sensory, emotional, and cognitive information. Memories can also be updated with the addition of new information, a process referred to as reconsolidation. In terms of course material, the retrieval required in a practice test will actually improve future performance.

The Role of Meaning in Memory

What if you were to learn information that had no meaning? How well would you remember this information? This question was posed by a German researcher in the 1880s, Hermann Ebbinghaus (1850—1909). Ebbinghaus wanted to make things very simple. He became the only participant in his research. He introduced strict controls in terms of timing and number of study trials. He also wanted to remove any meaning of the information that needed to be learned. In order to do this he invented the nonsense syllable. A nonsense syllable is composed of a consonant—vowel—consonant. Some examples would be MEQ, CAZ, and QON. He created more than 2,300 nonsense syllables and put them into random lists.

Ebbinghaus learned sequences of these nonsense syllables by repeating them out loud to himself. He kept careful records of the number of recitations required to learn each list. He did this for more than six years. Generally, he found that delay between memorization and recall resulted in the forgetting of a large portion of the material. This relationship is shown in Figure 7-5.

Figure 7-5 Ebbinghaus’s forgetting curve. Percent of the original information learned by Ebbinghaus in terms of time. Immediate recall was 100%.

As Ebbinghaus showed, we forget information over time. It is also the case that learning new information may be influenced by what we had learned previously. That is, we have a harder time remembering certain information. For example, if your favorite pizza parlor changes its phone number from 973—555—0175 to 973—555—0172, you may have more difficulty remembering the new number since the old one may interfere as you try to call. Technically, this is called proactive interference. Proactive interference is the case in which old information inhibits your ability to remember new information. You may also find that when you try to input a new password, the old one inhibits your ability to remember the new one. The opposite can also be the case. This is referred to as retroactive interference. This is the case in which new information inhibits your ability to remember old information. For example, you might have a new combination lock on your bicycle that you learn the combination to. Then you need to open the combination lock on a storage shed. Since you have had this lock for a number of years, the new bicycle combination lock could inhibit your ability to remember the old numbers.

From an evolutionary perspective, most of what we remember has significance for our lives, not nonsense syllables. We learn information that helps us to adapt, that protects us, that feeds us, that involves our friends, and helps us to find mates. That is, we remember things that have meaning to us. As noted previously, remembering is a constructive process that allows each recall of information to be a constructive event. We actually recreate each memory as we recall this. This is referred to as reconstructive memory.

In the 1930s Frederic Bartlett demonstrated the nature of reconstructive memory (Bartlett, 1932). He had British college students read a story about Native Americans called “The War of the Ghosts.” Bartlett had the students recall the story at different intervals after the first reading. He discovered that the memory of the story changed with each recalling. At times, new events were added, or the order of events was changed. One person remembered that the characters were hunting whales, an event that was not part of the story.

Bartlett suggested that when we remember something, we store the key facts. Later we reconstruct the memory and fill in the missing parts. This reconstruction generally involves our own perspective or point of view. In the process of reconstruction, there is the possibility for errors as seen in eyewitness testimony.

Bartlett’s work helped to establish a current view of memory. This perspective is to see memory as constructive rather than reproductive (see Schacter, Addis, & Bucknew, 2007; Schacter, 2012 for overviews). That is, we construct what we remember in our brain rather than just reproducing an exact copy of the information.

The importance of our understanding of information and how it relates to memory was studied in a classic experiment by John Bransford and Marcia Johnson (1972). Bransford and Johnson focused on the factors that influence how we remember and encode what we hear. They asked, do we remember information differently if we can put it in a particular context or frame of reference? Imagine that you are a participant in that experiment and you are asked to listen to and later recall the following passage:

If the balloons popped, the sound wouldn’t be able to carry since everything would be too far away from the correct floor. A closed window would also prevent the sound from carrying, since most buildings tend to be well insulated. Since the whole operation depends on a steady flow of electricity, a break in the middle of the wire would also cause problems. Of course, the fellow could shout, but the human voice is not loud enough to carry that far. An additional problem is that a string could break on the instrument. Then there could be no accompaniment to the message. It is clear that the best situation would involve less distance. Then there would be fewer potential problems. With face-to-face contact, the least number of things could go wrong.

After the passage was read, the participants were asked to rate how well they understood the passage, with a rating of 7 meaning it was highly comprehensible. You might try this yourself. If you are like the participants in the experiment, you will rate the material as incomprehensible. Their actual average rating was 2.3 on the 7-point scale. The next task for the participants was to recall what they had read. Here they were instructed to write the main ideas that they remembered from the passage. How many ideas did you remember? The research participants in the experiment recalled, on average, 3.6 ideas out of a possible 14.

A second group of participants was shown Figure 7-6 before they heard the passage. The participants in the group that saw the picture rated comprehensibility more than twice as high as those in the group who did not see the picture; they gave it a mean rating of 6.1 (versus 2.3 for the first group) on the 7-point scale. The second group also recalled many more ideas than the first group (8 versus 3.6 ideas). It is clear that having a context or schema in which to understand the information changes our ability to remember information. That is, we remember information best when we can make it part of a coherent story.

Figure 7-6 How does this help you understand and remember the passage?

Source: Bransford and Johnson (1972).

CONCEPT CHECK

1. What did Penfield’s treatment of people with epilepsy add to our understanding of memory and the brain?

2. Describe the important characteristics of each of these aspects of the temporal dimension of memory:

a. Sensory memory

b. Short-term memory

c. Long-term memory

3. How is chunking used in improving short-term memory? Give an example of how you could use it in your daily life.

4. Describe the important characteristics of each of these types of long-term memory:

a. Episodic memory

b. Semantic memory

c. Explicit memory

d. Implicit memory

5. Describe the important characteristics of each of the steps in learning and the long-term memory processes:

a. Encoding

b. Storage

c. Consolidation

d. Retrieval

e. Reconsolidation

6. What do the studies of Ebbinghaus, Bartlett, and Bransford and Johnson contribute to our understanding of the role of meaning in memory?

Memory and the Brain

For at least 2,000 years following the ideas of Aristotle, the brain was seen as a blank slate on which experiences and information was stored. Like a computer disk, new information is added and retrieved as needed. We now know that memory is not a passive process. Rather, our brain recreates experiences as we remember events. That is, remembering is an active process.

The German scientist Richard Semon (1859—1918) sought to describe memory in precise scientific terms. One of the terms he introduced was the engram or memory trace. During the last century, researchers such as Karl Lashley (1890—1958) sought to find the location of memory in the brain. His three-decades-long search for the engram led to a large number of studies, but he was unable to find a specific location in the brain in which memory resides.

In the middle of the 20th century, Donald Hebb (1904—1985), who was a student of Lashley’s, proposed a model of learning and memory. Hebb suggested that the experience of an object would be reflected in the neurons that are activated. That is, with each experience of an object, certain neurons in your brain would become active. Different experiences would result in different sets of neurons being active. That is, each experience would consist of a different internal representation of cells. Hebb referred to these cells that are activated as a cell assembly. Through repetition or other processes, the cell assembly could be strengthened and form a memory trace. That is, memory consolidation would occur as these cell assemblies became more efficient.

The basic model suggests that when one neuron in the brain excites another one nearby repeatedly, then the connection between the two is strengthened. This came to be described as “cells that fire together wire together.” One implication of this is that even if only a few cells of a well-established cell assembly are activated, this has the potential to activate the other neurons in the entire cell assembly. Thus, being able to remember one aspect of an event may lead to your remembering of the entire event.

One implication of Donald Hebb’s work is that memories of related items are associated with one another. If you enjoy long bike races, then all of the items related to the bicycle, the experiences of riding as well as methods of training could be seen as part of a larger network. One example of a network model as depicted by Allan Collins and Elizabeth Loftus (1975) is shown in Figure 7-7. This diagram shows the relationships between items. The shorter the path between items the stronger the connection. If you were talking about apples, then you could activate memories of other fruits or the perception of red more quickly than the items that make up your bicycle. Research has shown that if you were shown the word “red” and then asked to name a vehicle, you would more likely name a fire engine than a garbage truck. Likewise, if you were shown the word “cough,” and asked to name an experience, you would more likely say having a cold than having a sunburn. Although not shown in Figure 7-7, items can also be organized in terms of concepts such as colors or fruits. Further, there can be overlapping networks. For example, “comfort foods” may include not only specific types of food but also the places where you consume these foods.

Figure 7-7 A model of how information is stored in the brain. Shorter lines suggest that one item is more related to another.

Source: Collins and Loftus (1975).

As suggested by Hebb, these associations between items appear not only in our cognitions but also in our brain. That is, neurons in our temporal lobe are seen to respond to concepts that are related to one another (Ison, Quiroga, & Fried, 2015). In this study, it was shown that neuronal changes to new associations could be established in a few presentations of the new material. Neurons in other areas such as the hippocampus respond when the organism is moving through space. As you learned previously in Chapter 3, it has been shown that neurons in the hippocampus increase connections when London taxi drivers learned new routes. Although it is assumed that each memory has a unique representation in the brain in terms of neural connections, the exact nature of these connections is still being worked out (Guan, Jiang, Xie, & Liu, 2016; Josselyn & Tonegawa, 2020).

H.M. and Memory

We now know that one critical area involved in memory processes is the hippocampus, which is located in the temporal lobe (see Figure 7-1). In the 1950s, a patient known as H.M. had his hippocampus and nearby structures removed in order to treat his severe epileptic seizures. After the surgery, his seizures were greatly improved, but there was an unexpected event. He lost the capacity to form new memories. That is, he forgot daily events nearly as fast as they occurred. However, he did not have problems with language, attention, cognitions, or perceptual tasks.

Figure 7-1 Hippocampus is part of the temporal lobe of the human brain.

In a series of studies, the psychologist Brenda Milner detailed the nature of the memory problems seen in H.M. (Milner, Corkin, & Teuber, 1968). H.M., whose identity as Henry Molaison was revealed after his death in 2008, showed some memory abilities but not others. Molaison could remember events that took place before his surgery. He remembered his name, his occupation, and events from his childhood. He still could use English as well as he did previously, and his IQ was unchanged. However, he did not know words that appeared in English since the time of the operation, such as “jacuzzi,” “frisbee,” and “slamdunk.”

One important ability that Molaison did not have after the operation was to recall information regarding what he had just experienced. Said in more technical terms, he could not move information from short-term memory to long-term memory. Short-term memory as noted is the type of memory we use to accomplish tasks in the present, usually spanning less than a minute in time. We look up a phone number and make the call. We check an address when we arrive to see if we are at the correct location. If we need to use this information in the more distant future, we need to move it to long-term memory. After the operation, then, Molaison could not move information from short-term memory to long-term memory. He could not remember new people he met. Because Dr. Milner began to study Molaison after the operation, he reacted to her as if she were a new person each time they got together. He could not remember simple events that most of us take for granted, as shown in the following conversation:

Dr. MILNER: Do you know what you did yesterday?

H.M.: No, I don’t.

Dr. MILNER: How about this morning?

H.M.: I don’t even remember that.

Dr. MILNER: Could you tell me what you had for lunch today?

H.M.: I don’t know, to tell you the truth.

More information is available online (http://www.npr.org/templates/story/story.php?storyId=7584970).

Although he didn’t remember doing it, Molaison was also able to learn new tasks. As noted this is an example of implicit memory, which is the ability of information to influence our behavior and experiences without our being aware of the learning taking place

One of these tasks was the Tower of Hanoi puzzle (see Figure 7-8). As seen in the figure, you begin the task with all the disks on one peg. The task is to transfer all the disks to another peg. You are allowed to move only one disk at a time and may never place a larger disk on top of a smaller disk. Basically, you use the other two pegs to move the disks back and forth until they are all on one peg. After doing the task a number of times, you learn the best strategy to solve the puzzle.

Figure 7-8 Tower of Hanoi puzzle.

Molaison was able to learn the task, but each time he was shown the puzzle, he would respond that he had not seen it before. He showed similar abilities in learning to draw a star in a mirror. This required that he move his hands in the opposite direction from what he saw visually. After some days, he learned to do this as well as individuals without temporal lobe damage. However, he could not consciously remember ever having performed the task. This suggests that learning a task involves a different type of memory than recognizing the task or remembering your experience with it.

Although a tragic event, the operation that removed Molaison’s hippocampus helped to change the way we view memory. From her studies, Brenda Milner came to four critical conclusions regarding memory.

✵ The first is that the ability to acquire new memories is a distinct function of the brain located in the temporal lobes.

✵ The second is that the temporal lobes are not required for short-term memory.

✵ The third is that the temporal lobes and hippocampus cannot be the storage sites for long-term memories.

✵ And the fourth is that the temporal lobes are not the site for the memory of tasks such as the Tower of Hanoi puzzle.

Research involving Henry Molaison and others helped to develop a way to organize the different types of memory systems (Corkin, 2002; Squire, 2009).

Brain Areas Involved in Memory

We now know that different types of memory involve different brain regions that are connected together by cortical networks. We also know that some types of memory include conscious experiences and others do not (Squire, 2004). On the level of the neuron, we know that learning can influence connections of synapses with one another, as described previously in Chapter 3 with the research of Eric Kandel. The increase in connections can take place in all parts of the brain, which allows for greater activation in the future. Further, different brain areas connect with one another to allow for memories to involve any of the senses such as vision, hearing, and touch.

Working memory is a memory process in which a limited amount of information is retained for a short time. It is the information you need to accomplish your immediate task. MEG, EEG, and fMRI studies show brain changes, especially an increase in high-frequency cortical activity during working memory tasks (Constantinidis & Klingberg, 2016). Working memory involves the frontal lobes and their connections with parietal areas. The neurotransmitter dopamine in the striatum also plays a critical role in working memory (D’Esposito & Postle, 2015).

In essence, when we remember past events (long-term memory) our brain shows a pattern of activation that is very similar to how our brain responded to the initial event (Davachi & Preston, 2014). That is, it is as if every memory is a reenactment of the original event. You see your keys on the table, which allows you to later remember where you put them by reactivating this image in your brain. You may also have the bodily memory of throwing them on the table. Of course, how you seek to remember where your keys are could determine which brain areas are involved. If you logically ask, are the keys in my coat, in my car, in my house, you will use different parts of your brain than if you imagine driving home, getting out of your car, going into your house, and so forth (Sheldon & Levine, 2016).

As shown in the case of H.M., damage to parts of the medial temporal lobe impairs the ability to move events occurring in the present into long-term memory. In this way, it is critical to memory consolidation. Two specific areas that are parts of the medial temporal lobes are critically involved in memory networks; they are the hippocampus and the amygdala. The first area is the hippocampus, which is important to memory, especially spatial memory, as with the London taxi drivers. In fact, you saw that with the learning of the taxi routes of London, these taxi drivers showed changes in the size of their hippocampus. Earlier research with animals has also shown that different neurons in the hippocampus respond differently in terms of specific locations in space (O’Keefe, 1978). From this it has been suggested that the hippocampus is important for a spatial map of one’s world.

Overall, the hippocampus is involved in four aspects of memory. The first is spatial memory, as discussed. The second is the timing of events, such as would be seen in autobiographical memory. That is, we know events happened in a specific order in our life and the hippocampus works with other areas of the brain to determine which events are encoded with which other events. The third memory aspect is related to putting together sensory information—how did it smell and what did it look like and how did it feel—with other aspects of the task—such as did I like it and where did it take place. Fourth, as shown by the experience of H.M., the hippocampus is important in the consolidation of memories from short-term to long-term memory.

If we experience an event that is emotionally arousing, we remember it better. This was shown in early studies by James McGaugh (see McGaugh, 2015 for an overview). When we see a bear in the woods, our body reacts with a release of adrenaline (epinephrine) that excites our bodies and prepares us to protect ourself by running or fighting. If immediately after an animal learns a task, it is given an injection of epinephrine, then its ability to remember the task is enhanced. It is critical that the epinephrine be administered immediately after the learning has taken place. Further, this works with many different kinds of tasks. From an evolutionary perspective, it would be important to remember events that produce emotional arousal, as these usually are associated with pleasure or pain.

Specific emotionally arousing public events have come to be called flashbulb memories. Most generations of people have particular events that they feel they can remember vividly, such as the attack on Pearl Harbor, the assassination of John F. Kennedy, the Challenger explosion, the killing of Martin Luther King, the attack of September 11, 2001, the Boston Marathon bombing, the killing of Osama Bin Laden, the Sandy Hook Elementary School shooting, and the death of Prince. People will report that they remember exactly where they were when they heard the news and give vivid and elaborate descriptions with great certainty. Flashbulb memories typically refer to those events that a person heard about rather than being directly involved in. Although, in the past, flashbulb memories were thought to involve special memory systems, current research suggests they are part of normal memory mechanisms (Hirst & Phelps, 2016). Further, although remembered with confidence, they are subject to the same types of distortions as are other memory processes (Talarico & Rubin, 2003, 2007).

The region of the medial temporal lobe that is important for emotional processing is the amygdala. As you will learn in the chapter on stress, the amygdala is influenced in response to arousing material. Overall, experiences that are emotionally arousing are remembered better than routine events (see McGaugh, 2004, 2013 for overviews). We all remember specific birthdays, holidays, or other such events and can recall them easily. In one study using PET (positron emission tomography) to measure blood flow in the brain, it was shown that initial changes in the amygdala after individuals watched emotionally arousing videos correlated with how well they remembered the videos a few weeks later (Cahill et al., 1996). Another role of the amygdala in memory appears to be memory consolidation.

The frontal lobes of the brain are also involved in memory (Eichenbaum, 2017a, 2017b). When you ask where you left your keys, you want to remember information about your keys, not the material you learned for the test. In an amazing manner, we are able to recall the information we need from memory without being bothered with all the other information our mind contains. Thus, the frontal lobes help to coordinate information from memory for the task you are currently trying to execute. Figure 7-9 shows the types of long-term memory and the brain areas involved with each.

Figure 7-9 Are different areas involved with different types of memory? Yes.

Source: Squire (2004).

It is also important to understand that memory can be influenced by brain areas involved in other cognitive processes such as language production. If I were to ask you for an answer as to who was the singer and actress in The Wizard of Oz, how would you answer? You may immediately know the answer or not know it at all. If you know the answer, brain activity in the frontal and temporal regions will be seen. However, if you were shown a photo of Dorothy, you may say I recognize that actress, I know her name, but can’t produce it—it is as if it is on the tip of my tongue.

The tip of the tongue phenomenon is the inability to recall total information while having the feeling that you will be able to remember it at any moment. The tip of the tongue experience activates brain areas that involve both memory and language production as well as cognitive control (Shafto & Tyler, 2014). Brain activity continues for a longer period when the tip of the tongue is experienced than when the answer comes quickly, which suggests that brain networks continue to be active and complete the task of remembering the name. Brain areas involved in memory and language production include parts of the frontal, temporal, and parietal lobes, whereas cognitive control includes the insula, frontal areas and the anterior cingulate area. Brain activities in these areas is weaker than if a person is able to easily recall the name Judy Garland.

CONCEPT CHECK

1. How are memories stored in the brain? What has the research of Hebb and Collins and Loftus contributed to our understanding of memory networks?

2. How is the hippocampus critically involved in four different aspects of memory?

3. What four important conclusions about learning, memory, and the temporal lobes are illustrated by H.M.’s ability to successfully solve the Tower of Hanoi puzzle?

4. If we experience an event that is emotionally arousing, we remember it better. What is happening in the brain to facilitate this?

5. How is the frontal lobe involved in memory?

Individual Differences in Memory Abilities

Most of us have gone out to a restaurant with a number of our friends. Occasionally, you might have been surprised that even when there were ten or more people at the table, the server was able to take everyone’s order without writing it down. And even better, when the food arrived, everyone received what they ordered without the server asking who ordered which food.

There are even contests such as the National Memory Championships in which contestants learn names, spoken words, random numbers, and other such lists. Many of these individuals are successful by using some type of system to improve memory. For example, if you have a list of words to learn, you could imagine you were walking through your house or other familiar place. Each word in the list would then be associated with a particular place in the house. To do recall, you would simply imagine you are walking through your house and recall the word associated with each location. Psychologists are interested in how people achieve what appears to be exceptional memory performance.

Clearly people differ in their memory abilities. In this section, you will be introduced to some individuals who are able to display exceptional abilities in memory as well as those who have problems with different types of memory. In the feature The World Is Your Laboratory, you will read about individuals who can remember every day of their life.

The World Is Your Laboratory: Exceptional Memory Ability

We all remember important events in our life. However, on the days in between these events, we typically remember very little. That is the typical nature of our memory. However, what if you could remember every day? What would your life be like? One individual who could do this wrote an email to the memory researcher James McGaugh in the spring of 2000 that began a line of research on individuals with exceptional autobiographical memory, which is formally known as Highly Superior Autobiographical Memory (HSAM). The email stated:

I am thirty-four years old and since I was eleven I have had this unbelievable ability to recall my past, but not just recollections. My first memories are of being a toddler in the crib (circa 1967) however I can take a date, between 1974 and today, and tell you what day it falls on, what I was doing that day and if anything of great importance (i.e.: The Challenger Explosion, Tuesday, January 28, 1986) occurred on that day I can describe that to you as well. I do not look at calendars beforehand and I do not read twenty-four years of my journals either. Whenever I see a date flash on the television (or anywhere else 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 non-stop, uncontrollable and totally exhausting.

(Parker, Cahill, & McGaugh, 2006, p. 35)

Although James McGaugh and his colleagues were initially skeptical about this person’s memory abilities, Jill Price was also able to remember events from her life (McGaugh & LePort, 2014). Since she has kept diaries from the age of 10, it was possible to check her memory with information in the diary. Public events going on at the same time could also be checked from public sources. Ms. Price says her personal memories are vivid and full of emotion. She also said that her remembering is automatic. This was demonstrated to the researchers as she gave quick, immediate answers to their questions concerning what she did on a certain day in her past. She could also remember what happened in the world on a given day. When asked what happened on August 16, 1977, she quickly replied that this was the day Elvis Presley died.

Although Jill Price could remember every day of her life since age 11, there were other types of memory in which she was not exceptional. She did not remember which of the five keys on her key ring went to which lock. In neuropsychological testing, she did not excel in the ability to remember complex figures or recognize faces. She also did not show any exceptional ability to remember the story “The War of the Ghosts,” which Bartlett had used in his memory research discussed previously. Thus, she had exceptional memory abilities in autobiographical memory but not in some other types of memory.

After attention to Jill Price’s ability was brought to the public on a National Public Radio show in 2006, a number of other individuals wrote to James McGaugh to describe similar abilities (http://www.npr.org/templates/story/story.php?storyId=90596530). A later 60 Minutes show brought forth even more individuals (http://www.scientificamerican.com/article/remember-what-it-means-to-have-an-extraordinary-memory/). From these, McGaugh and his colleagues studied 11 individuals who clearly had exceptional autobiographical memory abilities. Like Jill Price, these 11 individuals showed exceptional autobiographical memory but performed similar to a control group on other types of memory. By about age 11 and a half, these individuals realized they had a highly developed knowledge of dates.

Brain-imaging studies of individuals with exceptional autobiographical memory showed differences from a control group in both white and gray matter in different areas of the brain (LePort et al., 2012). Further, the connection between those brain areas associated with autobiographical memory were stronger in the HSAM group (see Figure 7-10).

Figure 7-10 What brain areas are different in those with exceptional autobiographical memory? Two memory-related regions stood out in brain scans: the uncinate fascicle, a nerve fiber tract that links the temporal and frontal cortices, and the parahippocampal gyrus, which are better connected to other brain areas.

Source: McGuagh and LePort (2014).

Thought Question: What might be an advantage of having exceptional autobiographical memory? What might be a disadvantage?

Mnemonists

A mnemonist is a person who can remember and recall long lists of information such as numbers, words, or names. Interestingly, these individuals do not show superior autobiographical memory. Similarly, individuals with exceptional autobiographical memory do not display other superior memory abilities.

In the 1920s, a newspaper editor sent one of his reporters named Sherashevsky to the famous Russian psychologist A. R. Luria. The editor of the newspaper noted the reporter’s lack of notetaking and his ability to remember all of the information that was needed. Luria studied this individual who he referred to as S and wrote a book describing his abilities, The Mind of a Mnemonist (Luria, 1987). In essence, S was able to remember long lists. In fact, Luria could not find a memory test that S did not do well on.

However, this ability was not accomplished with ease. S had developed techniques for remembering information. One of his techniques, which has also been used by others with this ability, is to take a mental walk through a familiar route and to pair each item with a specific place on this walk. Using such a technique, S could remember information in either a forward or backward manner by imagining his walk beginning at different locations.

Another individual who demonstrated superior memory abilities was Rajan Mahadevan (Ericsson et al., 2004). As a child, he would surprise his friends by reciting the complete railway timetable for the Calcutta railway system. Later, to establish a place in the Guinness Book of World Records, he reproduced more than 30,000 numbers in the derivation of pi (3.141592 and so forth). Not only could he do this with pi but also with any string of digits that were presented to him. As with Luria’s description of S, Rajan Mahadevan had developed a technique based on a matrix approach that allowed him to remember numbers. However, this ability did not generalize to other types of memory.

Photographic Memory

It should be noted that the memory abilities shown by Sherashevsky and Mahadevan, impressive as they are, were based on techniques that required some effort to achieve. Although these are sometimes referred to as photographic memory, this was not the case. True photographic memory would suggest that the person could retrieve the image perfectly. However, research suggests that photographic or eidetic memory exists in only a small number of individuals, if at all (MacLeod, Jonker, & James, 2014).

Those who are able to reproduce an image with great accuracy are mainly children. In general, less than 10% of children are able to show signs of eidetic memory. By about age 10, this ability almost completely disappears. There are, from time to time, examples of individuals with exceptional long-term visual memory. The late neurologist Oliver Sacks (1995) describes two artists who were able to draw near perfect images from memory.

The artist Franco Magnani came to America from Italy in 1965. Although he did not go back to his home town of Pontito, he was able to able to draw in great detail his home town even after 30 years. Although he was able to remember his hometown, his drawing added some detail that was not be present in an actual photo. Still it is amazing that he was able to retain the visual information.

The second person Oliver Sacks wrote about was Stephen Wiltshire. Sacks wrote about Wiltshire when he was a teenager and was impressed that he could reproduce a drawing of Sacks’s house by just quickly looking at it. Since that time, Stephen Wiltshire has been profiled on the BBC in the UK and 60 Minutes in the United States. He has been able to take a helicopter flight of a major city such as Mexico City, Rome, New York City, or Singapore and then reproduce his view of it. A description of his work can be seen on YouTube (https://www.youtube.com/watch?v=g2EpmFzG2AM). In addition to being able to recognize cities, other individuals are able to recognize faces over a period of time. This situation is presented in the Applying Psychological Science: Super-Recognizers and Never Forgetting a Face box.

Applying Psychological Science: Super-Recognizers and Never Forgetting a Face

We recognize one another in a number of ways. We recognize how the other person walks, or the sound of their voice, or the shape of their face. In fact, humans are considered experts at processing faces. However, about 2% of the general population have difficulty recognizing faces even though they have normal vision. The inability to recognize faces is referred to as developmental prosopagnosia.

Not only do some people have problems recognizing faces, but others claim they never forget a face. Some say they can recognize a person seen in one movie or TV show, even if they play a small part in another. To test these claims, Richard Russell and his colleagues studied these individuals with face-recognition tasks that required both the recognition of familiar and unfamiliar faces (Russell, Duchaine, & Nakayama, 2009). What these researchers found was that the four super-recognizers as they were called were much better than 25 control subjects at the face-recognition tasks. More recent research has shown that the ability to memorize words and faces is not the same as the ability to recognize faces (Ramon, Miellet, Dzieciol, Konrad, Dresler, & Caldara, 2016).

Many people could use the ability to recognize faces in their occupation. This would be an advantage for salespeople in large stores. They could recognize the frequent shoppers and acknowledge this to the customer. However, stores do not typically actively search for individuals who are super-recognizers.

One organization that does actively seek super-recognizers is the London England Metropolitan Police. London has many closed-circuit cameras (CCTV) installed around the city of some eight million residents. What started as cameras being installed around government buildings and embassies has grown to one estimate of more than a million cameras, including those installed by businesses (O’Keefe, 2016). With this much information, the ability to recognize faces would give the police an advantage to be able to recognize individuals who are present during the time a number of different crimes were committed. Thus, the London police created a unit that is made up of individuals who share the ability to recognize and remember faces. In fact, the police called upon scientists to help them identify individuals for this unit.

In one situation, women reported being groped on London transit. By examining video, it was possible to note if anyone was present at each occurrence. This led to the man being identified in live video as he left a railroad station. In another situation, stores reported that a handsome man of about 40 years of age would come into a jewelry store or boutique. He would begin talking to the salesperson posing as a wealthy person seeking a gift for his girlfriend. The salesperson would show him an expensive gift. If the salesperson turned away, the man would take the expensive item and hide it in his clothes. After some forty acts of robbery involving more than $100,000, the police realized that they had a number of pictures of the man and were able to arrest him.

Of course, as with any good criminal investigation, other clues besides facial recognition are also employed. For example, some criminals wear the same clothes at each crime they commit. Others can be traced using transit cards they used. However, in many cases facial recognition is critical.

The unit was started in 2008 by Detective Chief Inspector Mick Neville. Patrick Keefe, a writer for The New Yorker magazine, spoke with the London Metropolitan Police and wrote an article, dated August 22, 2016, describing the super-recognizers unit.

Thought Question: What are some other occupations in which being a super-recognizer would be beneficial? What would be the benefit? What common aspects do these occupations share?

Memory Disorders

Memory problems can be seen after a variety of traumas. Many people who have a concussion, for example, will not be able to remember the period during which their head was hit. This is an example of a memory problem of only a few minutes. However, those who have had a stroke in which blood is not available to specific brain areas may be unable to recall specific information that they once knew. The inability to recall information is referred to as amnesia.

A distinction is often made between retrograde amnesia and anterograde amnesia. Retrograde amnesia refers to the situation in which a person cannot remember events prior to the trauma to the brain. Such a person may not be able to remember events, facts, or people that were known before the trauma. It is interesting that in some cases, memories from a few years prior to the trauma are not remembered, but memories from 20 or 30 years earlier are remembered. Depending on the location of the trauma to the brain, different people may show different types of memory deficits. The movie The Majestic (2001) shows a person with retrograde amnesia who has lost the memories of his personal past while still knowing language, and ways of human social interaction.

Anterograde amnesia, on the other hand, is the situation in which the person is not able to form new memories, as was the case with H.M. The movie Memento (2000) describes a person named Lenny who cannot form new memories. Likewise, the movie 50 First Dates (2004) describes a woman who could not form new memories and the man who romantically seeks to win her affections each new day. There can also be less severe cases in which it takes more practice for the person to form new long-term memories. In general, those with brain damage show signs of both retrograde and anterograde amnesia.

CONCEPT CHECK

1. Define each of the following superior memory abilities:

a. Highly Superior Autobiographical Memory (HSAM)

b. Mnemonists

c. Photographic or eidetic memory

d. Super-recognizers

2. What are anterograde amnesia and retrograde amnesia, and how are they different?

False Memories

False memory research has focused on the factors that cause us to remember an event in a manner that does not reflect that particular event accurately. If indeed when we remember an event we reconstruct it in our brains, can we be led to perform inaccurate reconstructions? The answer to this question turns out to be yes. This has important implications for eye-witness testimony in court, how information-gathering techniques of governments are to be evaluated, and the factors that influence our memory.

A false memory is one that is experienced as any other memory and you believe it to be true. One researcher who has focused her career on the nature of false memories and how to create them is Elizabeth Loftus who began her research at the University of Washington. She initially referred to false memories as the misinformation effect. Loftus describes her work in a Ted Talk (https://www.ted.com/speakers/elizabeth_loftus) and a segment of Radiolab (https://www.wnycstudios.org/story/91573-adding-memory).

The misinformation effect is based on the fact that we continue to reconstruct memories even after the experience has happened. In some of her early work, Elizabeth Loftus and her colleagues had participants watch videos of automobile accidents and then answer questions about the event (Loftus & Palmer, 1974). The nature of these questions was an important part of the study. For example, one group was asked, “About how fast were these cars going when they hit each other?” Another group was asked, “About how fast were these cars going when they smashed into each other?” A final group was not asked any questions about the one-minute accident video they saw.

The three groups then returned a week later and answered ten questions about the video they had seen. One question, for example, asked if the participant saw any broken glass during the accident—there was none. The group that heard the verb “hit” and the group that were not asked any questions both said there was not any broken glass. However, twice as many people in the group that heard the question with the verb “smashed” reported broken glass than those who did not. Thus, a false memory could be induced just by the manner in which a person is asked a question after an event.

Another procedure for inducing false memories is referred to as the Deese—Roediger—McDermott (DRM) procedure. Read the words presented in Table 7-1. Once you do this, close the book and write down all the words you can remember (based on Roediger & McDermott, 1995).

Source: Based on Roediger and McDermott (1995).

How many words did you remember? But, more important for the false memory situation, did you remember a word that was not there? If you are like many people, you included the word sleep, which was not on the list. The point is that we remember things in terms of their meaning to us. Each of the words in the list is related to sleep, so we assume it was there. Thus, what something means to us is critical for how we remember information. Further, as noted previously, we remember information in terms of networks or interconnection between different pieces of information. Remembering the words dream, nap, and drowsy activates the network that would also contain the word sleep.

Another way you can create false memories is through the use of imagination. Giuliana Mazzoni and Amina Memon asked college students at the University of Aberdeen in Scotland to imagine either a frequent or an impossible event (Mazzoni & Memon, 2004). The frequent event was having a tooth pulled by a dentist. The impossible event was having a school nurse remove a skin sample from their little finger. This is an impossible event since school nurses in the UK are not allowed to take skin samples. A week previously, all of the participants had filled out a 20-item questionnaire on which they rated the possibility that an event had happened to them before the age of 6. This included such items as finding money in a parking garage, feeling an earthquake, and becoming ill and going to the hospital.

In the experiment a week later, one group of students imagined having a tooth pulled by a dentist and read a one-page passage about the skin sample. A second group of students imagined having a skin sample taken and read a passage about having a tooth pulled. A week later all participants repeated the 20-item questionnaire of which event happened to them as well as report any memories they have of the tooth and skin event and three other noncritical events. At no point during the experiment did the researchers try to convince the participants that any particular event had happened to them.

As expected, those who imagined or read about a tooth being pulled reported more memories about that event. However, in relation to the event that did not happen, a school nurse taking a skin sample, imagining the event increased the number of individuals who reported that the event had happened to them. They also reported more memories about this event. Thus, individuals can develop a memory of an event that did not happen simply by imagining its occurrence.

Imagination has also been shown to influence students in the United States. What if someone took you on a walk around a familiar college campus, and asked you later what you saw or did? What if the researchers asked if you saw someone shake hands with a fire hydrant or propose to a Pepsi machine? Most of us would say we would know if we saw such events. We would also assume that we would accurately remember what we did or saw. However, that turns out not to be the case.

In a creative study, each student in the experiment was asked to walk around his or her campus with a researcher and a confederate of the researcher (Seamon et al., 2009). On the first day, the student went on a walk on which they stopped at 48 locations. At each location, the experimenter read an action statement and either performed that action or asked the participant to imagine themselves performing that action. Half of the actions were familiar and half were bizarre, such as proposing to a Pepsi machine. A day later, the participant was taken on another walk. On this walk they stopped at 36 locations. These stops included 24 locations they had stopped at previously and 12 new locations. On this walk, the participant was asked to imagine the experimenter performing each action. Again, half of the actions were familiar and half bizarre.

Two weeks later, the participant and the confederate were asked about certain actions and whether they happened or were imagined on the day one walk. The confederate and the participant alternated their responses to an event. On some events, the confederate was accurate, on some inaccurate, and on others, said that he or she did not remember. Following this, the experimenter said that they were to be tested alone for additional information. Then, the participant was tested alone and asked if a particular action was presented on a particular day and, if so, was it performed or imagined. The participant was also asked to rate how confident they were in their answer.

Overall, participants had trouble remembering and distinguishing events that were experienced or viewed in comparison to imagined events. For example, both familiar and bizarre events were remembered as happening on the first walk if they were merely imagined on the second walk.

As human beings, we fill in the gaps of our memory to make things work. We also tend to remember events in a way that fits into our own conception of the world. Politics is one area of life in which many people have strong feelings. In May 2010, Slate.com invited its readers to complete a survey about their perspectives on various political events. Those who volunteered read about five unrelated news events with accompanying photographs and were asked about their memories for them. The five events from 2010 were a Hillary Clinton attack ad, Cheney/Edwards debate, an Obama handshake, the Lieberman vote, and the Bush vacation. Unbeknownst to the respondents, one of the five events they were asked about was a complete fabrication; it never happened at all. More than 5,000 respondents completed the study (Frenda, Knowles, Saletan, & Loftus, 2013).

Figure 7-11 Example of real (on the left) and altered photo (on the right). The real photo was taken on President Bush’s ranch with the baseball player Roger Clemmons at the same time Hurricane Katrina was hitting the coast.

Source: Frenda, Knowles, Saletan, & Loftus (2013).

The initial part of the survey ensured that the participants were familiar with the events. A total of 82% of the participants reported knowing of all three true events and 98% said they knew of two of the three. In terms of the false events for which each person only saw one example, 50% reported that they remember that particular event as having taken place. The other participants said that they did not remember the event (44%) or that they remembered it differently (6%). Participants in the Hillary attack ad condition showed the highest rate of false memory (68%), followed by the Cheney/Edwards debate (65%), the Obama handshake (47%), the Lieberman vote (40%), and the Bush vacation (31%). A follow-up study showed that false events are more easily accepted if they are similar to the person’s previously existing attitudes.

False memory research has led to changes in legal procedures (Loftus, 2003; Schacter & Loftus, 2013). Schacter and Loftus described a crime that happened in Camden, New Jersey, on New Year’s Day 2003. Larry Henderson was accused of holding a gun on James Womble while another man shot Rodney Harper to death. Larry Henderson was not involved in the crime. Almost 2 weeks after the murder, Womble identified Henderson from a photograph. Womble again identified Henderson at trial, and Henderson was easily convicted of reckless manslaughter and aggravated assault, among other charges.

The case was appealed to the New Jersey Supreme Court, which resulted in the court issuing a new set of guidelines that reflected the reconstructive nature of memory and the various factors that can influence it. Specifically, jurors are now to be told that memory is not like a video recording, and it is not foolproof but can be influenced. Research has also shown that those in authority such police officers, military personnel, and emergency responders are susceptible to memory errors during challenging incidents (Hope et al., 2016).

In addition to problems with eye-witness testimony, police investigations at times ask leading questions, suggest events that did not happen, or pressure the person to report details that may be inaccurate. In fact, individuals may come to believe that they participated in or committed a crime that they did not. Research related to this is discussed in the following Myths and Misconceptions box.

Overall, false memory research has focused on the factors that cause us to remember an event in a manner that does not reflect that particular event accurately. As you have seen, there are a variety of ways that we remember events in a different manner than which they initially occurred. If indeed when we remember an event, we reconstruct it in our brains, we can be led to perform inaccurate reconstructions. This has important implications for eye-witness testimony in court, how information-gathering techniques of governments are to be evaluated, and the factors that influence our memory.

Myths and Misconceptions: What You Remember is True

In 2015, Julia Shaw and Stephen Porter sought to determine if completely false memories of committing crimes involving police contact could be created in a laboratory setting. The study asked if college students could be convinced that they had committed a crime when they were between the ages of 11 and 14 years of age. To begin with, the researchers sent questionnaires to the parents and caregivers of the participants. They were asked to report at least one highly emotional event that happened during their child’s adolescence. Individuals were ineligible if their caregivers mentioned any kind of police contact or reported events that resembled the target events at any point during adolescence. On the questionnaire, caregivers were asked whether their child had experienced any of six negative emotional events, three of which were criminal (assault, assault with a weapon, and theft) and three of which were noncriminal (an accident, an animal attack, and losing a large amount of money). For each recalled event, caregivers were asked to write a description of what they could remember, including the location, people present, time of year, age of the participant, and how confident they were that the event had occurred.

The participants in the study completed three interviews, about one week apart. In the interviews, the participants were presented verbally a true event that happened to them and a false one that they did not experience. Participants were then asked to add any information about the true and false memory. The interviewer added accurate information such as the city the person lived in, the name of a friend who was said to be part of the event, the season the event took place in, and other such information. When the participants had difficulty recalling the false event, the interviewer encouraged them to try to remember it. They were also told to try to visualize the event during the period between the interviews. The interviewers also suggested that they had additional information from the parents but did not give it as the memories needed to come from the participant.

The false memories during the interviews were based on six types. That is, participants were assigned to one of six false memory groups. The individuals in the first three groups were told that they had committed a crime in adolescence that was either an assault, an assault with a weapon, or a theft. The next three groups were told they had experienced a non-criminal emotional event during which they injured themselves, had been attacked by a dog, or got in trouble with their parents about losing money.

Overall, participants in the study reported more confidence in remembering the true memory events. However, they still reported specific details in the false memory condition. The results of this study showed that over 71% of those in the criminal false memory groups indeed reported false memories. Specifically, 75.6% reported details in the assault group, 71.3% reported details in the assault with a weapon group, and 67.2% reported details in the theft group. In the non-criminal conditions, some 76.7% reported false memories. The percentages in each of the three non-criminal groups were similar.

The Shaw and Porter study points to the ability of researchers in a laboratory setting to have individuals come to visualize and recall detailed false memories of both criminal and non-criminal behavior. In fact, these false memories were richly detailed. If this can be accomplished in a relatively benign laboratory setting, one can wonder the degree to which police or other government settings are able to induce false information. The Innocence Project (http://www.innocenceproject.org), which seeks to free those who have been wrongfully convicted, suggests that about 25% of false convictions are related to faulty confession information. Thus, both faulty eye-witness testimony and questionable interrogation tactics leading to false memories set the stage for miscarriages of justice.

Thought Question: What information do you think it would be helpful for all individuals to have to minimize the effects of false memories in areas of criminal and civil justice?

CONCEPT CHECK

1. What are three different ways for inducing false memories? How does each of them work?

Summary

Learning Objective 1: Discuss memory and how information is encoded, stored, and retrieved.

Memory is focused on how information is encoded, stored, and later retrieved. Before information is stored, it is encoded. That is, certain aspects of your experiences are organized and stored in the brain. Encoding includes how you store information in the brain. Although we use terms such as storing a memory, we now know that remembering an experience is more than just viewing an image of what happened. Unlike a computer that gives you back exactly the information that is stored, our brain has a logic of its own based on our evolutionary history. When we remember, we actually recreate the experience in our minds. Depending on the nature of the memory, different parts of your brain can be involved. Some memories have to do with language, some with emotions, some with events, some with sensory experiences, and many with a combination of these. Overall, memory is described in terms of two different dimensions: (1) the temporal dimension which includes short-term and long-term memory; and (2) the type of information stored.

Sensory memory lasts only a few seconds and takes place in all of our senses. If it involves the auditory system, it is referred to as echoic memory. If it involves our visual system, it is referred to as iconic memory. This is the first step of how we remember information. Sensory memory lasts just long enough for the information to be processed by our brain. However, we can’t possibly remember all of the information that is before us in this brief period.

The second step in remembering information is to transform the sensory information and work with it for a short period of time. This is referred to as short-term memory or working memory. As the name implies, short-term memory lasts for less than a minute. The concept of working memory evolved from short-term memory to reflect the systems required to keep things in mind while performing tasks. Short-term memory lasts for about 20 to 30 seconds without rehearsal. To have a memory available to us in the future, the information needs to be converted from short-term memory into long-term memory. Information available to us through long-term memory can be relatively permanent. Long-term memory can be classified in terms of the type of information that is stored.

We now know that one critical area involved in memory processes is the hippocampus, located in the temporal lobe. In the 1950s, a patient known as H.M. had his hippocampus on both sides of the brain and nearby structures removed in order to treat his severe epileptic seizures. After the surgery, his seizures were greatly improved, but there was an unexpected event. He lost the capacity to form new memories. Although a tragic event, the operation that removed H.M.’s hippocampi helped to change the way we view memory. From her studies with H.M., Brenda Milner came to four critical conclusions regarding memory: (1) the ability to acquire new memories is a distinct function of the brain located in the temporal lobes; (2) temporal lobes are not required for short-term memory; (3) the temporal lobes and hippocampus cannot be the storage sites for long-term memories; and (4) the temporal lobes are not the site for the memory of tasks. Overall, memory is described in terms of two different dimensions: (1) the temporal dimension, which includes short-term and long-term memory; and (2) the type of information stored.

Episodic memory is a collection of events that we personally experienced. Semantic memory has to do with impersonal facts and everyday knowledge. Implicit memory has the ability to influence our behavior and experiences without an awareness of the learning taking place. We also can do a number of motor tasks without consciously remembering how to do it. This type of memory is referred to as procedural memory. Other types of implicit memory include classical conditioning and priming. Priming is the situation in which previous experiences can influence present behavior.

Psychologists have described the long-term memory processes in terms of four separate steps.

1. The first step is encoding. Encoding is the process by which information is attended to and connected with other information in your memory. Following encoding, the information must be stored.

2. The second step, storage, involves those areas of the brain and neural mechanisms by which memories are retained over time.

3. The third step is consolidation. Consolidation is the process by which the information stored becomes even more stable. Consolidation takes place in the brain on two levels. The first level is structural changes at the synapse; the second level involves a reorganization of long-term memories over brain networks.

4. The fourth step is retrieval. This stage is what we think of when we say we recalled something. Typically, retrieval involves different types of information stored in different places throughout the brain.

Learning Objective 2: Describe how memories are organized and stored in the brain.

We now know that different types of memory involve different brain regions, which are connected together by cortical networks. We also know that some types of memory include conscious experiences and others do not. On the level of the neuron, we know that learning can influence connections of synapses with one another. The increase in connections can take place in all parts of the brain, which allows for greater activation in the future. Further, different brain areas connect with one another to allow for memories to involve any of the senses such as vision, hearing, and touch.

Working memory (short-term memory) is a memory process in which a limited amount of information is retained for a short time. MEG, EEG, and fMRI studies show an increase in high-frequency activity during working memory tasks. Working memory involves the frontal lobes and their connections with parietal areas. The neurotransmitter dopamine in the striatum also plays a critical role in working memory.

In essence when we remember past events (long-term memory), our brain shows a pattern of activation that is very similar to how our brain responded to the initial event. That is, it is as if every memory is a reenactment in the original event. Damage to parts of the medial temporal lobe impairs the ability to move events occurring in the present into long-term memory. In this way, it is critical to memory consolidation. Two specific areas that are parts of the medial temporal lobes are critically involved in memory networks—the hippocampus and the amygdala.

The first area is the hippocampus, which is important to memory, especially spatial memory. In fact, it has been suggested that the hippocampus is important for a spatial map of one’s world. The hippocampus is involved in four aspects of memory: (1) spatial memory; (2) the timing of events such as would be seen in autobiographical memory (that is, we know events happened in a specific order in our life and the hippocampus works with other areas of the brain to determine which events are encoded with which other events); (3) putting together sensory information—how did it smell? what did it look like? how did it feel?—with other aspects of the task—did I like it? where did it take place? and so forth; (4) as shown by the experience of H.M., the hippocampus is important in the consolidation of memories from short-term to long-term memory.

Specific emotionally arousing public events have come to be called flashbulb memories. People will report that they remember exactly where they were when they heard the news and give vivid and elaborate descriptions with great certainty. Flashbulb memories typically refer to those events that a person heard about rather than being directly involved in. Although, in the past, flashbulb memories were thought to involve special memory systems, current research suggests they are part of normal memory mechanisms. Further, although remembered with confidence, they are subject to the same types of distortions as are other memory processes.

Learning Objective 3: Describe how people differ in their memory abilities.

Clearly people differ in their memory abilities. You might have been surprised in a restaurant that even when there were ten or more people at the table, the server was able to take everyone’s order without writing it down.

Memory problems can be seen after a variety of traumas. Many people who have a concussion, for example, will not be able to remember the period during which their head was hit. This is an example of a memory problem of only a few minutes. However, those who have had a stroke in which blood is not available to specific brain areas may be unable to recall specific information that they once knew. The inability to recall information is referred to as amnesia. Retrograde amnesia refers to the situation in which a person cannot remember events prior to the trauma to the brain. Depending on the location of the trauma to the brain, different people may show different types of memory deficits. Anterograde amnesia, on the other hand, is the situation in which the person is not able to form new memories.

Learning Objective 4: Discuss the key theories of how we create false memories and misinformation.

A false memory is one that is experienced as any other memory and you believe to be true. False memory research has focused on the factors that cause us to remember an event in a manner that does not reflect a particular event accurately. If indeed when we remember an event, we reconstruct it in our brains, can we be led to perform inaccurate reconstructions? The answer to this question turns out to be yes. This has important implications for eye-witness testimony in court, how information-gathering techniques of governments are to be evaluated, and the factors that influence our memory.

Research has shown that a false memory could be induced in several ways, including (1) just by the manner in which a person is asked a question after an event; (2) by using the Deese—Roediger—McDermott (DRM) procedure. We remember things in terms of their meaning to us and each of the words in the list in the example is related to sleep, so we assume it was there. Further, we remember information in terms of networks or interconnection between different pieces of information. Remembering the words dream, nap, and drowsy activates the network that would also contain the word sleep. (3) By the use of imagination: imagining the event increases the number of individuals who reported that the event had actually happened to them. They also report more memories about this event. Thus, individuals can develop a memory of an event that did not happen simply by imagining its occurrence.

False-memory research has led to changes in legal procedures. A case was appealed to the New Jersey Supreme Court, which resulted in the court issuing a new set of guidelines that reflected the reconstructive nature of memory and the various factors that can influence it. Specifically, jurors are now to be told that memory is not like a video recording, and it is not foolproof but can be influenced. Research has also shown that those in authority such as police officers, military personnel, and emergency responders are susceptible to memory errors during challenging incidents. In addition to problems with eye-witness testimony, police investigations at times ask leading questions, suggest events that did not happen, or pressure the person to report details that may be inaccurate. In fact, individuals may come to believe that they participated in or committed a crime that they did not.

Study Resources

Review Questions

1. What does it mean when we say that memory is a constructive process rather than a reproductive process? What are the implications of describing memory in that way?

2. Identify the four types of exceptional memory abilities that were described in this chapter. How is each of them unique? What do they have in common?

3. What are false memories? How are they different from real memories? How can we know that we ever reconstruct an event accurately?

For Further Reading

✵ Foer, J. (2011). Moonwalking with Einstein. New York: Penguin Press.

✵ Kandel, E. (2006). In Search of Memory. New York: Norton.

Web Resources

✵ Clive—https://www.wnycstudios.org/podcasts/radiolab/segments/91578-clive

✵ H.M.—http://www.npr.org/templates/story/story.php?storyId=7584970

✵ Extraordinary memory—https://www.npr.org/templates/story/story.php?storyId=90596530

✵ Extraordinary memory—https://www.scientificamerican.com/article/remember-what-it-means-to-have-an-extraordinary-memory/

✵ Stephen Wiltshire—https://www.youtube.com/watch?v=g2EpmFzG2AM

✵ Elizbeth Loftus—https://www.ted.com/speakers/elizabeth_loftus) and (https://www.wnycstudios.org/podcasts/radiolab/segments/91573-adding-memory)

✵ Innocence Project—http://www.innocenceproject.org

Key Terms and Concepts

amnesia

anterograde amnesia

cell assembly

chunking

consolidation

encoding

episodic memory

explicit memory

false memory

implicit memory

long-term memory

memory

proactive interference

procedural memory

reconstructive memory

retrieval

retroactive interference

retrograde amnesia

semantic memory

sensory memory

short-term memory

storage

working memory