A model for processing information or learning, cognition and memory looks like the one found in Figure 1.1. In this model, based on the work of Frank Smith (2004), working memory and short-term memory appear as two different, but overlapping, memory systems. The distinction is important in describing how the brain processes information that could result in a prediction.
Short-term memory is very limited in its capacity for storage. New information can push other information aside. For example, have you ever tried to remember a phone number being told to you only to realize that you forgot why you were calling? In short-term memory, information must be used, and needs to be used quickly, or it will be forgotten.
Figure I: A Model of Information Processing
Short-term memory is too limited in the amount of information it can store and in the length of time before memory decays without rehearsal to complete complex cognitive functions. In other words, short-term memory has limited use in making predictions. We cannot make predictions about the meaning of a complex sentence unless we are able to store sufficient information about individual words while also reading ahead to determine which other words might make change the meaning of the sentence as a whole.
Try an example. Read the sentence fragment below and focus on the word “running.”
I am running…
At this point in the sentence, you have some idea that you (as the first-person “I”) have become the subject of the verb, and you know that the verb is running. You do not know yet what other contexts to bring to bear to determine exactly what “running” means, though. You will have to read the rest of the sentence to get that information all the time retaining the possible meanings for the word until you can reduce the uncertainty you have about the eventual meaning of the sentence. If the meaning is that you have an errand to attend to quickly, then the sentence could be:
I am running to the store to buy milk and eggs.
But if the meaning is that you will have to propel yourself very quickly on foot, then the sentence could be:
I am running a marathon tomorrow at noon.
The final determination of the meaning of the word and thus of the sentence has to be stored and integrated as the rest of the sentence is read, possibly with preceding sentences or those that might follow.
“Do you have the results of the test?” asked Maria? “I am running the analysis software, right now,” replied Bill.
Ah, now you know that running, in this case, refers to executing or processing information on a computer. To make sense of the final sentence, you needed to pull your knowledge about computers forward from long-term memory into working memory.
Working Memory: Pulling Stored Knowledge Forward
Working memory allows the thinker to bring long-term memory to bear along with information stored in short term memory until such time as
- the problem is solved,
- the information integrated or
- the effort abandoned.
Working memory, described by Baddeley (2001), is a means of temporarily storing and maintaining information during complex cognitive processes. This is particularly relevant to our discussion of predictions and how they are made because, in predicting, the thinker brings forward relevant information from long-term memory and integrates it with any new information already in working memory applying it to the problem at hand. As you remember from the class discussion Mr. Jackson facilitated, Kaila used her working memory (that “Greece isn’t a big deal now”) to shape her thinking about the text she was reading and the discussion she was having with others.
Long-term Memory and Prior Knowledge
Memories that the thinker has stored for later retrieval may be thought of as long-term. When you remember your first-grade teacher, the smell of a favorite aunt’s perfume, the structure of the Bohr atom, or the birthdates of your children, you’re using long-term memory. Memories that are stored in a long-term memory reservoir have been characterized in various ways by different researchers. They have been referenced as schemata (Bartlett, 1932), prior knowledge, nonvisual information (Smith, 2004), cognitive structure, and learning (Dechant, 1991). Regardless of the label, a common feature of long-term memory is that it changes the structure of neurons. These changes occur through a process of rehearsal and meaningful association between what is already known and the new information being considered. Of course, long-term memory is not always permanent; we all have experience with the natural forgetting process associated with long-term memory.
Arrangement or organization is the basis of long-term memory. How we organize information is at least as important as the information itself. Without storing information in a particular order or hierarchical structure, the retrieval of relevant information would not be possible.
Types of Long-Term Memory
Theories of long-term memory suggest that humans use classification systems to aid their memory. In these systems, the capability of using memory to organize ideas roughly follows evolutionary lines. Humans use all three types of long-term memory for survival. In addition, humans use all three types of long-term memory for learning. Let’s consider each of these and how they related to learning experiences.
Procedural memories, the use of objects or movements of the body, are the most ancient form of memory and the one we share with animals. Organisms that rely solely on procedural memory respond to external stimuli and adapt to the environment accordingly. In school, we use procedural memories to move around, to multiply numbers, to write, and so on. Procedural memory is critical to the basic functioning of a living organism.
Nested inside our procedural memory is something called semantic memory. Semantic memory permits a person to visualize that which is not actually present at the time. Tulving (1985) suggested that semantic memory allows the thinker to construct and manipulate “mental models” (p. 387) of the world.
You can, for example, create a mental model of a pencil and what it’s used for, even when the object is not right in front of you. Semantic memory also allows us to create mental models of ideas. Your mental model of summer vacation may be different than those around you, but we can discuss our shared understanding of summer vacations with one another. We can think of semantic memory as the type that allows the thinker to manage and relate memory purposefully.
The third type of memory, episodic, permits a thinker to consider events personally experienced in the past, including the emotions of the experience. Among other things, episodic memory makes it possible for the thinker to recall the past and to use that information in constructing an understanding of the present. Consider, for example, the student who has had wonderful experiences at school interacting with teachers. These episodic memories help the student construct his or her participation in the class. Similarly, readers use episodic memories as they read. For example, recalling fresh snow and the emotions of that experience, serves to activate memories that are used in understanding how a specific character in a specific book might react. In other words, episodic memory influences our background knowledge.
We can see the usefulness of this model if we consider the examples from the beginning of this book and this section. As you read about words that shared the same Latin root as “prediction” you were able to employ semantic memory to associate words and to see the associations between the words we suggested. When you read the opening paragraphs of the introductions, you probably thought of various predictions you made recently, which demonstrated your episodic memory. You might have remembered the last time the football team played at home, the traffic was terrible. This caused you to predict that the traffic might creep along again today because there is a game. Finally, we should clarify that teachers and linguists often think of semantics in terms of words and their meaningful relations in sentences. Here, the term takes on a much broader meaning, which includes more than just the meanings of words. Semantic memory also includes an understanding of the function of the idea the word names.
Schemata and Existing Knowledge
As we have discussed, there are several theories or models of long-term memory. Each explains aspects of how we clarify, order, and store representations of the world as we perceive it. Memory is such a complex aspect of being human that no single theory can, at present, fully account for it. Therefore, it isn’t necessary to think of one theory as being correct, or even more correct, than another. Taken together, we build an increasingly accurate understanding of how memory works and what aspects of memory make us uniquely human. One other theory of memory that makes us uniquely human is how we ‘build schema’ to order information we take into our long term memories.
A schema (Bartlett, 1932) is a hierarchical representation of knowledge, in other words, a plan for memories. The theory explains how long-term memory traces might be structured so that memories might be retrieved as they are needed. Here is how it might work.
Prediction depends on existing knowledge. Imagine that a researcher leads you blindfolded into a classroom after school. The teacher and students are gone. The blindfold is removed and your only task is to determine if the class that meets in the room is a primary or upper elementary grade, a middle school grade, or a high school grade. In just an instant, you would be able to give a fairly accurate assessment of the grade level. You could do this without reading anything that might indicate what the grade level is because the size of the desks and chairs and other room paraphernalia would indicate that the room was designed for a specific age group of children.
To visualize a first-grade classroom, you needed to recognize what you observed as elements of a first-grade room (small desks, big books, etc.), visually sample the rest, and draw your conclusion based on the map or plan you have in your memory for this concept. Organization of the memory traces associated with this concept makes it possible to retrieve all the elements in a search for the overall pattern.
If the first-grade classroom is somewhat familiar to you, then we can draw one of two conclusions. You went to the same first grade classroom that the book’s authors attended, or more likely, your first-grade classroom looks a lot like ours. A learning theorist would term the degree of accuracy of the mental model to the reality of the concept as veridical. This concept is important and goes back to our earlier discussion about reducing uncertainty. Increasing veridicality means reduced uncertainty.
It may help you to construct this new schema for “veridical” by thinking of other concepts you know that are similar. As you read the word, you notice that the first three letters are the same as in the word, “very” and, in fact, the “y” and “i” may have similar roots in the way the words are pronounced. Your schema for “very” tells you that it is an adjective or adverb that is used when a speaker or writer wants to emphasize the precision or truth of whatever the topic happens to be. This reminds you that the coat of arms for Harvard University has the word “veritas” on it. Even if you didn’t attend Harvard, you may remember that it has something to do with truth and that it is Latin. Simultaneously, you think of the word “veracity” which you read in this morning’s paper in an article about a reporter checking to make sure his source told an accurate story. If you are an English major, you might even remember the word “verisimilitude” which describes a quality of good fiction that appears to represent a truth about the condition of being human.
In this process, you are activating several existing schemata for words that share the same root and making predictions about what the word might mean. Of course, readers don’t limit their use of schemata to words. As Louise Rosenblatt (1978, 1995) noted, readers construct meaning from text through a transactional process. She believed that what the reader brought to the text was at least as important as what the author may have intended.