Encoding Information into Memory

There are three essential processes in our memory system—encoding, storage, and retrieval. Encoding is the process of transferring information from one memory stage to the next (from sensory into short-term memory and from short-term into long-term memory). Storage refers to the process of maintaining information in a particular stage. Storage is temporary except for in long-term memory. Retrieval is the process of bringing information stored in long-term memory to the conscious level in short-term memory. Let’s go back to the flow chart of the three-stage model of memory in Figure 5.1. Encoding and retrieval determine the flow of information within the three-stage system. Information is first encoded from sensory memory to short-term memory where it can be stored temporarily. Information is then encoded from short-term to long-term memory where it is stored more permanently, but can be retrieved and brought back into short-term memory when we need to use it.

In this section, we will cover encoding and its role in moving information from short-term into long-term memory. Our focus will be on the best ways to achieve this transfer. We begin with a consideration of general encoding strategies.

How We Encode Information

The first distinction to consider is automatic versus effortful processing (Hasher & Zacks, 1979). Automatic processing is processing that occurs subconsciously and does not require attention. In contrast, effortful processing is processing that occurs consciously and requires attention. For a particular type of processing to become automatic, much practice is needed. A good example is reading. At first, learning to read is very effortful, but after years of practice it becomes easier and more automatic. Wouldn’t it be nice if encoding to learn (studying) were an automatic process? It is unlikely that studying can become as automatic as reading, but we can get better at it by using better encoding strategies and practicing these strategies. In this section, we’ll discuss some better ways to encode. If you practice them, your encoding (and your memory) will improve.

Levels-of-processing theory.

Remember that encoding is the process of transferring information from one memory stage into another. Here we are interested in encoding from short-term to long-term memory. Encoding information into long-term memory is related to retrieving information from long-term memory. Some types of encoding lead to better retrieval. The levels-of-processing theory describes what types of encoding lead to better retrieval (Craik & Lockhart, 1972). This theory assumes that incoming information can be processed at different levels, from the simplistic physical level to the semantic level, and that semantic processing, especially elaborative semantic processing, leads to better memory. According to this theory, there are three general levels of processing—physical, acoustic, and semantic. To understand the differences among these three levels, consider processing the word “brain.” We can process it as a string of lowercase letters. This would be the physical level. Next we could process “brain” by how it sounds, the acoustic level, which is a little deeper than the physical level. Third, we can process what “brain” means and then elaborate upon that meaning by relating it to what we know about parts of the brain and brain chemistry.

Let’s consider an experiment to see how these three levels may lead to different levels of memory performance. Researchers presented participants with a long list of words one at a time, but manipulated the level of processing of the words by manipulating the task to be performed on each word (Craik & Tulving, 1975; Experiment 2). For each word, one of three types of questions had to be answered. One type of question required processing the word at a physical level (for example, “Is this word in capital letters?”). A second type of question required acoustic processing (for example, “Does the word rhyme with bear?”). The third type of question required semantic processing (for example, “Will the word fit in the sentence, The man placed the______on the table?”). Participants did not know that they would be tested for their memory of the words. They only thought that they had to answer a question about each word. However, the experimenter later surprised the participants with a memory test for the words. Levels-of-processing theory predicts that memory for the words that had to be processed semantically should be best, those processed acoustically next best, and those only processed physically worst. This is exactly what was found (see Figure 5.7). Long-term recognition memory was the best for the words encoded semantically, next best for those encoded acoustically, and worst for those only encoded physically.

Elaborative rehearsal.

Maintenance rehearsal, the repetitive cycling of information in short-term memory, was discussed earlier in the chapter. This type of rehearsal serves to maintain information in short-term memory. Levels-of-processing theory, however, views this type of rehearsal as shallow, acoustic rehearsal. It is not very effective in producing good long-term memory for information. Semantic processing is much better. Once at the semantic level of processing, though, we should engage in elaborative rehearsal—rehearsing by relating the new material to information already in long-term memory. The memory organization created by the integration of the new information with existing information leads to more successful retrieval of the information than shallower processing. This organization provides more retrieval cues (links with other information in long-term memory) for the new information, thereby facilitating its retrieval. For example, to elaborately encode the concept of elaborative rehearsal, you could relate it to other concepts that you learned recently by thinking about such things as how elaborative rehearsal is different from maintenance rehearsal, how it relates to levels-of-processing theory, and how it is an example of effortful processing. Such elaboration enables much better long-term memory.

In elaborative rehearsal, you should try to relate the new information to information you know well. Because you know yourself so well, you should elaborate by tying the new information to yourself. To learn new concepts, you should personalize them by thinking of examples of these concepts in your own experiences. It is easier to remember information that you have related to yourself. This is called the self-reference effect, and it is a well-established research finding (Symons & Johnson, 1997). For example, researchers have found that people can remember more words from a list if they related the words to themselves (Rogers, Kuiper, & Kirker, 1977). Participants were asked whether list words such as “generous” applied to them. Later recall of such words was very good, even better than for words processed at the semantic level (as in the Craik and Tulving study). Think about how this might work. What if the word were “honest”? You would start thinking about incidents in your life in which you were honest and in which you were not. The word would then be linked to all of these incidents, facilitating its later recall. So when you are studying a new concept, try to find examples of it in your own life. For some concepts this is easy to do; for others it isn’t. However, it’s worth the effort because such connections will help you to remember the concept through the self-reference effect.

Environmental effects on encoding.

The fact that elaborative rehearsal improves memory stems from a larger principle—the encoding specificity principle (Tulving, 1983). In simple terms, the encoding specificity principle proposes that the cues present during encoding serve as the best cues for retrieval. This is why the various concepts and examples that you relate to a new concept during elaborative rehearsal help you remember the concept. They were present during encoding so they serve as good retrieval cues. Such cues are internal environmental cues; they refer to internal cognitive processing, what you were thinking about during rehearsal. Encoding specificity also applies to the external environmental cues present during encoding. Many research studies have shown that long-term memory is better when the physical study and test environments are as similar as possible. For example, in one rather dramatic demonstration of this, participants learned and were tested either underwater or on land (Godden & Baddeley, 1975). The two groups that had the same study and test environments (both were underwater or both were on land) remembered significantly better than the two groups that had their study and test environments reversed (one underwater and the other on land, or vice versa). However, you need not rush to classrooms to study. Classroom environmental effects on college exam performance are not very strong (Saufley, Otaka, & Bavaresco, 1985). Why? External environmental effects on learning diminish when the learning has taken place in several environments (Smith, Glenberg, & Bjork, 1978). In the case of exams, students have successfully learned the relevant information in a variety of environments ranging from the classroom to nonclassroom environments such as the library and dormitory rooms, thereby overriding the classroom environmental effect.

Figure 5.7 Differences in Recognition Memory for Words Processed at Different Levels Participants were presented a long list of words one at a time and had to answer a question about each word as it was presented. The nature of the questions led to different levels of processing—physical (how it was printed), acoustic (how it sounded), or semantic (what it meant). The level of processing dramatically affected the participants’ later ability to recognize the word as one that had been on this list.

(Adapted from Craik & Tulving, 1975; Experiment 2.)

Callahan. Courtesy of Levin Represents.

We have limited our discussion so far to a rather narrow definition of internal environment—a person’s mental activities at the time of encoding. Broader internal environmental factors, such as a person’s physiological state or mood, also impact encoding and retrieval. These effects lead to a phenomenon known as state-dependent memory, memory that depends upon the relationship of one’s physiological state at time of encoding and retrieval. The best memory occurs when people are in the same state at retrieval as they were at encoding, and memory is hindered by state differences. For example, people under the influence of alcohol at time of encoding would recall best if under the influence at the time of retrieval. Please note, however, that memory under the influence of alcohol, regardless of the state at the time of retrieval, is very poor. It is best to encode and retrieve in a nonalcoholically influenced state.

There are similar effects on memory that depend on the relationship between a person’s emotional states, such as being happy or sad, at time of encoding and retrieval. Because one’s mood is involved, these effects are referred to as mood-dependent memory, the retrieval of a particular memory is better when a person’s mood at retrieval is the same as it was during encoding. Like state-dependency effects, mood-dependency effects furnish support for the encoding specificity principle—context is important for successful memory retrieval. There is also a related phenomenon called the mood-congruence effect—the tendency to recall memories that are congruent with a person’s current mood. A particular mood cues memories that are consistent with that mood (Eich, 1995). We tend to remember more positive events when we are feeling good and more negative events when we are feeling down. These events have been associated with the accompanying emotions. Thus, the emotions serve as retrieval cues for the events. This congruence effect may hinder recovery in depressed people because they will tend to remember negative events and not positive ones. In fact, this is the case. Depressed patients report more memories related to illness, injury, and death than nondepressed people (Schacter, 2000). Think positively, and the mood-congruence effect will help maintain that positive attitude.

In summary, elaborative rehearsal is the most effective strategy for encoding. Research has found that actors working to learn their lines use elaborative rehearsal including encoding specificity, mood-congruence effects, and the self-reference effect (Noice & Noice, 1997). They do not use shallow processing and just memorize their lines. (Neither should students try this in their courses!) Elaborative rehearsal is the key to more effective learning. It is important to practice this type of rehearsal. You should integrate information that you are trying to learn with as much other information in your knowledge base as you can, especially relating it to yourself. You will get better at this elaboration strategy as you practice it, and learning will become easier.

How to Improve Encoding

In this section, we will discuss a few more specific ways to improve memory. We’ll start with some techniques to improve memory for lists and more organized sets of concepts. These techniques use a mnemonic, a memory aid. Mnemonics are useful for remembering lists of items, especially ordered lists, speeches, and long passages of text. We’ll start with a mnemonic that was used by ancient Greek orators to remember speeches.

© 1994 by Sidney Harris.

The Greek orators used a mnemonic called the method of loci (Yates, 1966). “Loci” is the plural of “locus,” which means place or location. In the method of loci, the sequential pieces of information to be remembered are first associated with sequential locations in a very familiar room or place. Then, when retrieving the information, one would merely mentally go around the room (or place) and retrieve the item stored at each sequential location. The Greek orators would mentally store the major points of a speech at sequential locations in the room where they were speaking. Then, during the speech an orator would go from location to location within the room to retrieve the key points of his speech. If you were trying to remember an ordered list of items for an exam, you could pair the items systematically with locations within the classroom and then during the exam mentally go from location to location within the classroom to retrieve them. The method of loci is a type of elaborative rehearsal using mental imagery. You elaborate upon items that you want to remember by visually associating them with a series of locations that you already know well or that will be available at the time of recall.

All mnemonics work by using some type of elaboration. In another mnemonic, the peg-word system, you visually associate the items in a list with a jingle that you first memorize. The jingle is “One is a bun, two is a shoe, three is a tree, four is a door, five is a hive, six is sticks, seven is heaven, eight is a gate, nine is swine, and ten is a hen.” You then associate each successive item in the list with the object for each successive number. For example, the first item on the list would be associated visually in a mental image with bun. If the word to be remembered were “dog”, then you might construct an image of a big bun with a dog in it. Then, as you go through the peg words, you retrieve the associated image, so you can retrieve the list.

One might think that these mnemonic techniques require much more effort than just memorizing the information that we want to remember. But researchers have found that people using mnemonics demonstrate much better memory than those who have just attempted to memorize a list. Why? As we discussed earlier, elaborative rehearsal is better for encoding into long-term memory. Professional memory experts do not have exceptional intelligence or structural brain differences but rather have their own unique mnemonic techniques and are superior at using them (Maguire, Valentine, Wilding, & Kapur, 2003). Their techniques, like the ones that we have described, are all essentially based on elaborative encoding, the key to superior memory. For a fascinating journey into the world of these memory experts, you should read Joshua Foer’s engaging book, Moonwalking with Einstein: The art and science of remembering everything (2011). Under the tutelage of some of these experts, Foer went from being a journalist with an average memory to winning the U.S. Memory Championship in 2006, testifying to the effectiveness of mnemonic techniques.

Mnemonics that involve little elaboration have not been found to be very effective. A good example is the first-letter technique (Gruneberg & Herrmann, 1997). In the first-letter technique, you compose a word, acronym, or sentence from the first letters of the words you want to remember. This is the mnemonic that we suggested in Chapter 3 to use to remember the colors of the spectrum (the name ROY G. BIV—Red, Orange, Yellow, Green, Blue, Indigo, Violet). This mnemonic helps, but it is not as effective as the other, more elaborative mnemonics, especially for more complex information.

So what else—in addition to elaborative rehearsal and the use of mnemonics—improves encoding and retrieval? There are three concepts that will help: (1) distributed study is better than cramming, (2) practice makes perfect, and (3) testing enhances memory. The superior memory for spaced study versus cramming is called the spacing (distributed study) effect. Your memory will improve if you distribute your studying for an exam over the entire preparation interval and not just the few days before the exam (Payne & Wenger, 1996). Hundreds of experiments have shown the benefits of distributed study (Cepeda, Pashler, Vul, Wixted, & Rohrer, 2006) In fact, for best results, distribute study and cram. The more you study, the more you learn. Overlearning, continuing to study material past the point of initial learning, improves memory (Rohrer & Taylor, 2006). Remember what we said about practice and automatic processing. Continued practice will make retrieval more automatic. Such practice may not make you “perfect,” but you’ll definitely do better. Lastly, don’t just study. Incorporate repeated self-testing during your distributed study periods. Such testing will enhance your memory by allowing you to practice retrieval, which is what exams require (Roediger & Karpicke, 2006). Don’t wait for an exam to test your retrieval; test it regularly during study. It will not only help you to practice retrieval but also help to guide your study by pointing out what you have learned and what you have not learned.