If information in a lecture is to become part of your permanent memory, it must be processed in three sequential stages: first in sensory memory, then in working mem- ory, and finally in long-term memory. The three stages work like an assembly line to convert a flow of incoming stimuli into meaningful patterns you can store and later reconstruct. This three-stage model, originally developed by Richard Atkinson and Richard Shiffrin (1968), is now widely accepted—with some elaborations and modi- fications. Figure 5.3 shows how information flows through the three stages. (Caution: Don’t get these three stages confused with the three basic tasks of memory we covered earlier.)
Sensory memory, the most fleeting of the three stages, typically holds sights, sounds, smells, textures, and other sensory impressions for a maximum of a few seconds. Although sensory memory usually operates on an unconscious level, you can see its effects in the fading luminous trail made by a moving flashlight or a twirling Fourth- of-July sparkler. You can also hear the effects of fading sensory memories in the blend- ing of one note into another as you listen to a melody. In general, these short-lived images allow us to maintain incoming sensory information just long enough for it to be screened for importance by working memory.
Working memory, the second stage of processing, selectively takes information from the sensory registers and makes connections with items already in long-term storage. (It is this connection we mean when we say, “That rings a bell!”) Working memory holds information for up to 20 to 30 seconds (Nairne, 2003), making it a useful buf- fer for temporarily holding a name you have just heard or following directions some- one has just given you. Originally, psychologists called this stage short-term memory (STM), reflecting the notion that this was merely a short-term, passive storage bin. Research has discovered, however, there are multiple active mental processes working at lightning speed to process information in this stage—hence the newer term working memory.
Long-term memory (LTM), the final stage of processing, receives information from work- ing memory and can store it for long periods—sometimes for a lifetime. Information in
sensory memory The first of three memory stages, preserving brief sensory impressions of stimuli.
working memory The second of three memory stages, and the one most limited in capacity. It preserves recently perceived events or experiences for less than a minute without rehearsal.
long-term memory (LTM) The third of three memory stages, with the largest capacity and longest duration; LTM stores material organized according to meaning.
The Three Stages of Memory (simplified)
Memory is generally thought to be divided into three stages of processing. Every- thing that eventually goes into long-term storage must first be processed by sensory memory and working memory.
Sensory memory Long-term memory
What an Eidetiker Sees
The combined images from the Do It Yourself! box form a number pattern.
Source: Klatzky, R. (1980). Human Memory: Structures and Processes. San Francisco: W. H. Freeman and Company. Copyright © 1975, 1980 by W. H. Freeman and Company. Used with permission.
Check Your Understanding 1. ANALYSIS: What is a major objection to the “video recorder”
model of human memory?
2. RECALL: What are the three essential tasks of memory?
3. ANALYSIS: Suppose you have just adopted a new cat. You note her unique markings so you can recognize her among other cats in the neighborhood. What would a cognitive psychologist call this process of identifying the distinctive features of your cat?
4. UNDERSTANDING THE CORE CONCEPT: Which of the following memory systems reconstructs material during retrieval?
a. computer memory b. human memory c. video recorder memory d. information recorded in a book
Answers 1. Unlike a video recorder, which makes an accurate and detailed record, memory stores an interpretation of experience. 2. Encoding, storage, and retrieval 3. Encoding 4. b
Study and Review at MyPsychLab
long-term memory includes all our knowledge about the world, from an image of your mother’s face to the lyrics to your favorite song and the year that Wilhelm Wundt estab- lished the first psychology laboratory. (Do you remember the year from Chapter 1?)
Our Core Concept captures the three stages in brief:
Core Concept 5.2 Each of the three memory stages encodes and stores memories in a different way, but they work together to transform sensory experience into a lasting record that has a pattern or meaning.
Our focus in this section will be on the unique contributions each stage makes to the final memory product (see Table 5.1). More specifically, we will look at each stage in terms of its storage capacity, its duration (how long it retains information), its struc- ture and function, and its biological basis.
The First Stage: Sensory Memory Your senses take in far more information than you can possibly use. While reading this book, they serve up all the words on the page, sounds in the room, the feel of your clothes on your skin, the temperature of the air, the slightly hungry feeling in your stomach. . . . How does the brain deal with this multitude of sensory input?
It’s the job of sensory memory to hold the barrage of incoming sensation just long enough for your brain to scan it and decide which stream of information needs atten- tion. But just how much information can sensory memory hold? Cognitive psycholo- gist George Sperling answered this question by devising one of psychology’s simplest and most clever experiments.