++
The working memory should be thought of as a system that incorporates characteristics and functions traditionally associated with sensory, perceptual, attentional, and short-term memory processes. Working memory operates in all situations requiring the temporary use and storage of information and the execution of memory and response production processes (see Baddeley, 1995). Baddeley (2003) stated that the working memory is a limited capacity system, which temporarily maintains and stores information and provides "an interface between perception, long-term memory, and action" (p. 829). As such, working memory includes memory functions traditionally ascribed to short-term memory, as well as other functions typically associated with the attention-related processes we discussed in chapter 9 (Engle, 2002).2
+++
Working Memory Functions
++
Working memory is both a place where information is stored for a short time and a functionally active structure. These two characteristics of working memory enable people to respond according to the demands of a "right now" situation. To do this, working memory plays a critical role in decision making, problem solving, movement production and evaluation, and long-term memory function. With regard to influencing long-term memory function, working memory provides essential processing activity needed for the adequate transfer of information into long-term memory. Finally, it is important to note that an important working memory function is to serve as an interactive workspace where various memory processing activities can occur, such as integrating the information in working memory with information that has been retrieved from the more permanent, long-term memory.
++
working memory a functional system in the structure of memory that operates to temporarily store and use recently presented information; it also serves as a temporary workspace to integrate recently presented information with information retrieved from long-term memory to carry out problem-solving, decision-making, and action-preparation activities.
++
A CLOSER LOOK Pitching in Baseball: A Demonstration of the Interactive Workspace Function of Working Memory
The situation. You are a baseball catcher or coach who needs to decide which pitch the pitcher should throw next. To make this decision, you must consider information about both the present situation and past experiences. In terms of the present situation you need to consider who the batter is, the score, who and where the runners on base are, the number of outs, the locations of defensive players in the infield and outfield, the ball and strike count, and so on. In terms of past experiences you need to consider the batter's batting history in similar situations, the opposing team's tendencies in this situation—especially if they have runners on base—the pitcher's history of pitching in similar situations, and so on.
Working memory involvement. The working memory serves as a temporary workspace to enable you to integrate the information about the present situation and past experiences so that you can select the best pitch for right now. After receiving your pitch choice, the pitcher will involve the working memory to retrieve from long-term memory the invariant characteristics of the type of pitch required and then use the temporary workspace to apply specific movement-related features to the pitch, such as speed and location. After the pitch is delivered, the information in working memory is deleted to provide space for new information to allow the pitcher to respond to what the batter does or to throw the next pitch you select.
++
According to Baddeley's conception of working memory, its functions are related to three subsystems. The first two subsystems store different types of information. One is the phonological loop, which is responsible for the short-term storage of verbal information. Second is the visuospatial sketchpad, which stores visually detected spatial information for short periods of time. The third subsystem, the central executive, coordinates the information in working memory, which includes information retrieved from long-term memory. Neurologically, these components of working memory are localized in various brain regions, including the parietal cortex, Broca's area, premotor cortex, occipital cortex, and the frontal cortex (Baddeley, 2003).
++
Because working memory stores and processes information, it is important to consider each function separately. In terms of storing information, two characteristics of working memory are essential to understand: the length of time information will remain in working memory, which is called duration, and the amount of information that will reside in working memory at any one time, which is called capacity.
+
++
++
Our understanding of the duration of information in working memory comes from research that investigated short-term memory. Peterson and Peterson (1959) were the earliest to report research related to the remembering of words presented one time each. They showed that we tend to lose information (i.e., forget) from working memory after about only 20 to 30 sec. The first experiment published relating working memory storage duration to motor skills was by Adams and Dijkstra in 1966. Their experiment indicated that arm positions in space that are experienced one time each are lost from working memory at a rate comparable to that of words.
++
The results of many other studies that followed the Adams and Dijkstra investigation generally supported the conclusion that the duration of movement information in working memory is about 20 to 30 sec. Information that is not processed further or rehearsed is lost.
++
A CLOSER LOOK Experimental Procedures to Assess the Duration of Movement Information in Working Memory
The classic experiment by Adams and Dijkstra (1966) set the standard for the procedural protocol researchers have used to investigate the question concerning the duration of movement information in working memory. Because the researchers were interested in movement information, their procedures were designed to require participants to use only proprioceptive information to perform the task.
Apparatus. An arm-positioning apparatus consisted of an almost friction-free handle that could be moved left or right along a metal trackway. This apparatus sat on a table facing the participant in the experiment.
Task. To begin a trial, a blindfolded participant moved the handle of the apparatus along the track-way to a location specified by a physical block (the criterion arm position to be remembered). After returning the handle to the starting point and waiting for a certain amount of time (the retention interval), the participant performed a recall test by moving the handle to his or her estimate of the arm position just experienced (the physical block had been removed). The experimenter recorded the location and the participant returned the handle to begin a new trial, which involved moving to a new position along the trackway.
Determining duration. To determine the length of time movement location information stayed in working memory, the researchers compared various durations of the retention interval. They determined the accuracy of the participants' recall movements for each retention interval length. Duration of the memory for the arm position was assumed to be related to the degree of accuracy of the recall movement. As you can see in figure 10.2 below, arm-positioning recall accuracy decreased (i.e., error increased) very sharply for retention intervals up to 20 sec, and continued to decrease for longer interval lengths.
++
++
We are concerned with not only how long information will remain in short-term storage, but also how much information we can accommodate. The issue of capacity in working memory was originally presented by George Miller in 1956, in an article that has become a classic in the memory literature. Miller provided evidence to indicate that we have the capacity to hold about seven items (plus or minus two items), such as words or digits, in short-term storage. To increase the "size" of an item in memory involves a control process termed organization, which we will consider later in this discussion. The newly created larger item, or "chunk" as Miller called it, enables people to recall far more than five to nine individual items at a time. However, research has shown that although the size of a chunk may increase, working memory's capacity for storing them remains constant at about seven (Cowan, Chen, & Rouder, 2004; Mathy & Feldman, 2012). Thus in terms of storage capacity, items maintained in working memory can vary in size. One of the problems researchers have experienced in investigating the capacity limit of working memory is determining how to objectively define and measure an "item" or chunk.
++
The definition and measurement problem has been especially problematic for researchers interested in motor skills who are interested in testing Miller's capacity hypothesis in terms of the remembering of movements. In spite of this problem, a few researchers have reported investigations of the capacity limits of working memory for movements. In general, their results agree with the 7 ± 2 range proposed by Miller. For example, in one of the first investigations of this issue, Wilberg and Salmela (1973) reported that an eight-movement sequence of arm-positioning movements was the upper limit of working memory capacity for movements. In another study, Ille and Cadopi (1999) asked twelve- and thirteen-year-old female gymnasts to reproduce a sequence of discrete gymnastics movements after watching the sequence one time on a videotape. The gymnasts' recall performance demonstrated a six-movement capacity limit for the more-skilled gymnasts and a five-movement limit for the less-skilled gymnasts. The results for these young gymnasts are in line with those reported by Starkes, Deakin, Lindley, and Crisp (1987) for young skilled ballet dancers, who showed evidence that an eight-movement sequence was their capacity limit.
++
To account for research evidence that has shown that highly skilled individuals (i.e., experts) seem to have a working memory capacity that is greater than that of the general population, Ericsson and Kintsch (1995) proposed a memory mechanism they called long-term working memory. In addition to having a larger working memory storage capacity, experts also show evidence that performing certain secondary tasks does not interfere with their performance of the activity at which they are skilled. Experts in an activity use long-term working memory when they must have access to a large amount of relevant knowledge at their disposal to use while performing the activity. In addition, the experts use long-term working memory to integrate new information with previously acquired knowledge. It is important to note that as is commonly characteristic of expertise (which we will discuss more fully in chapter 12), long-term working memory is skill specific, which means that it develops as expertise in a skill rather than being a common component of working memory.
+++
Processing Activities
++
Information that is active in working memory is processed (or manipulated) in such a way that it can be used to achieve the goal of the problem at hand. The goal may be to remember what you have just been told or shown to do so that you can do the task. Or you may need to use this information to solve a specific movement problem. And in both cases, you would like to remember what you did in each performance situation so that you can use your experience as a reference to help you in some future performance situation. In each case, you will involve working memory processing activities to enable you to achieve different goals.
++
Consider some examples of motor skill performance situations in which these different working memory processing activities could occur. Suppose your golf instructor has just given you a specific instruction to concentrate on your hand position as you swing a golf club. You must not only remember this instruction as you swing, but also retrieve from long-term memory the correct hand position and evaluate your present hand swing compared with the ideal. Of course, how successfully you make this comparison on your own depends on your stage of learning. But carrying out this verbal instruction invokes the working memory.
++
A CLOSER LOOK The Influence of Emotion on Memory of an Event: Recalling Details of Two Yankees versus Red Sox Championship Games
A study by Breslin and Safer (2011) presented an interesting approach to providing evidence that positive and negative emotionally arousing experiences are recalled more accurately than experiences where neither emotion is involved. More than 1,500 baseball fans who reported having attended, watched, or read about the 2003 and 2004 American League Championship games between the New York Yankees and Boston Red Sox (a well-known rivalry even when no championship is at stake) were asked to complete a questionnaire about each game. The participants were identified as Yankee fans, Red Sox fans, or neutral in their support for either team.
Method and questionnaires: Prior to answering the questionnaires about the games, the participants were each reminded that the Yankees won the 2003 game and the Red Sox won the 2004 game. The questionnaires asked participants to recognize and recall details about the two games and to rate their own subjective memories about the games. The items of interest to the researchers, which were identical on each questionnaire, asked:
What was the final score of each game?
Who were the winning and losing pitchers for each game? (a multiple-choice list)
What was the location of each game (New York or Boston)?
Did the game require extra innings?
Results: The following were the main results of this study:
The correct responses to the questions showed similar accuracy for all the participants.
Accuracy was higher for the fans that supported one of the teams than for the neutral fans.
Yankees fans recalled more details accurately for the game the Yankees won.
Red Sox fans recalled more details accurately for the game the Red Sox won.
Fans reported remembering the game their team won more vividly than the game their team lost.
Fans reported thinking about the game their team won since the time of the game.
Conclusion: Consistent with research of autobiographical memories, most individuals relive and recall more often and vividly memories that are positive rather than negative.
++
Suppose you have just watched a dancer perform a sequence of dance movements and you must now perform that sequence. Working memory processing activity would be involved because you must keep in memory the visually presented sequence of movements and translate that visual information into motor performance. Involved in this translation process would be retrieving from long-term memory the movement information required to carry out the sequence.
++
Consider also the following example. You are a patient in an occupational therapy session and are given a complex puzzle to put together. You study the pieces and try to determine how the specific pieces fit together. You continually try to match pieces as in the completed puzzle. And you try to determine an appropriate movement strategy that would allow you to put the pieces together quickly and with little error. Working memory would be actively involved in this problem-solving situation because you carried out several activities requiring several different perception, remembering, and performance characteristics that must be done virtually simultaneously.