The Human Memory System

Human memory is composed of three interconnected memory stores. Information from our senses is initially stored in sensory memory (SM) in the same manner that it processed by our senses (e.g., as images or sounds). Although information is retained in SM for less than two seconds, that is long enough for us to interpret it and to decide which parts of it are important enough to pay attention to and transfer to working memory (WM), where we can continue to process it. Information in WM is stored primarily in terms of how it sounds (i.e., acoustically), and only about 7 bits of information (e.g., numbers, letters, or words) can be held in WM for only about 30 seconds unless we continue to maintain them by repeating them to ourselves. Forgetting occurs in WM when we transfer more information from SM into WM—and therefore exceed our 7-item capacity—or if we stop repeating the information currently stored in WM. This repetition process, known as rehearsal, serves two purposes. First, it allows us to maintain information in WM as long as we continue to repeat it to ourselves. Second, rehearsal enables us to transfer information we wish to remember more permanently to our third and final memory store, known as long-term memory (LTM). Information in LTM is stored predominantly in terms of its meaning (i.e., semantically), and this memory store is often compared to a library whose contents are organized in a number of different meaningful ways (e.g., by subject matter, by authors' names, in alphabetical order, etc.). We may not always be able to retrieve information from LTM, when we want to—in the same way that a book in a library may be sometimes hard to find—but once it is there, it is stored relatively permanently, and we do not forget it in the same manner that we forget information that has been stored only in SM or WM.

1. Which of the following types of memory stores information for only about 30 seconds?

a. SM b. WM c. LTM d. none of the above

This question tests your ability to recognize that a specific concept (e.g., WM) is associated with a single, important characteristic (e.g., it lasts for only about 30 seconds). This requires you merely to memorize a term and its definition.

2. Which of the following is true about WM?

a. It can hold only about seven bits of information.

b. Information stored in it is mainly encoded acoustically.

c. Information stored in it lasts only about 30 second unless it is rehearsed.

d. all of the above

This question measures your ability to learn a set of characteristics common to a particular concept (e.g., WM can hold only a certain amount of information in a certain form for only a certain period of time). It requires a more thorough knowledge of a concept than does Question 1, but is still based primarily on memorization.

3. Which of the following is the correct sequence through which information passes as it is processed by the human memory system?

a. SM --> WM --> LTM b. WM --> SM --> LTM c. SM --> LTM --> WM d. WM --> LTM --> SM

This question requires you to learn a chronological relationship among a series of variables (e.g., SM, WM, and LTM).

4. Joan looked up a phone number, closed the phone book, and repeated the number to herself as she was dialing the phone. This phone number is being stored in __________.

a. SM b. WM c. LTM d. none of the above

This question measures your ability to apply knowledge to a real-life situation and requires a deeper understanding of the concept that goes beyond mere memorization of its definition or characteristics.

5. WM is to LTM, as __________ is to __________.

a. 7, unlimited b. semantic, acoustic c. relatively permanent, 30 seconds d. all of the above

This question measures the ability to compare and contrast two concepts (e.g., WM and LTM). This skill is based on—but goes beyond—the simpler abilities of memorizing a concept's definition (from question 1) and its set of characteristics (from question 2).

6. Which of the following students has given the best explanation of why Tom has already forgotten the name of the person to whom he was introduced only three minutes ago?

a. Chang: "The name was never in Tom's WM."

b. Monique: "The name was lost from Tom's LTM."

c. Fritz: "Tom did not successfully transfer the name from his LTM to his SM."

d. Juanita: "Tom did not successfully transfer the name from his WM to his LTM."

This question involves all the cognitive skills measured by the first five questions, plus it requires you to evaluate the knowledge you have acquired so that you can produce a logical decision based on a thorough understanding of a relational concept (e.g., factors that affect the successful transfer of information from WM to LTM) that can be used to explain an example of complex human behavior (e.g., forgetting).

How well did you perform on this quiz? If you performed well, you possess the ability to retain, understand, apply, compare, contrast, and evaluate the information you will encounter in this class. Now all you need is the motivation to work hard so you can actualize your academic potential. If your performance on this quiz was less than spectacular—and you would like to avoid this type of performance on your tests in this class—then you should spend some time analyzing why you missed the questions that you did. If you are like most students who take this quiz and perform below their expectations, you probably answered the first two or three questions correctly, but then began to experience difficulty as you attempted to answer the later questions that required you to apply, compare, contrast, or evaluate your knowledge. If this is the case, give careful consideration to your personal understanding of what it means "to study" a textbook assignment. If studying means making sure that your eyes see every word in a reading assignment and memorizing the important terms and their definitions, then I urge you to change your idea of what it means "to study." To answer the later questions on this quiz, you must assume an active approach to studying in which you ask yourself some of the following questions as you progress through your reading assignment.

1. Do I really understand this information or have I just memorized it?

2. Could I apply this information to a "real life" situation?

3. Could I relate this information to other information in this assignment?

a. Is it part of some type of sequence?

b. Is it similar to other information and, if so, how is it similar?

c. Is it different from other information and, if so, how is it different?

4. Could I use this information to evaluate the validity (i.e., truthfulness) of a statement?

When you ask yourself these questions as you read an assignment—and read actively to discover the answers—you will be engaging in a method of study that will increase your comprehension of the material you are reading and increase the probability that you will perform well on tests. Take this exercise and its results seriously. If you find yourself performing more poorly in this class than you would like, review this exercise again as the class progresses. I have been teaching classes in introductory psychology and study skills for more than a third of a century, and this is the best advice I have found for my students who ask the question, "How can I do better in this class?"

This handout was created by Dr. Drew Appleby, Indiana University-Purdue.