Working Memory versus Short-Term Memory

Many cognitive psychologists and memory experts view short-term and working memory as interchangeable or consider one to be a subtype of the other.

Other theorists and researchers contend that working memory Opens in new window and short-term memory Opens in new window are distinguishable constructs—a perspective promoted in this literature.

Regardless of which view the reader adopts, it is important for assessment and intervention purposes to recognize the contrasts between short-term memory (STM) and working memory (WM).

The chief differences are:

• STM passively holds information; WM actively processes it.
• STM capacity is domain specific (verbal and visual); WM capacity is less domain specific.
• WM has stronger relationships with academic learning and with higher-level cognitive functions.

• STM automatically activates information stored in long-term memory; WM consciously directs retrieval of desired information from long-term memory.
• STM has no management functions; WM has some executive functions.
• STM can operate independently of long-term memory; WM operations rely heavily on long-term memory structures.
• STM retains information coming from the environment; WM retains products of various cognitive processes.

Short-term memory Opens in new window and working memory Opens in new window are separable, and short-term memory can function without working memory.

Nonetheless, short-term memory and its measurement are included in this literature, mainly because the predominant theories of working memory incorporate short-term memory as a subsidiary system.

Accordingly, the majority of empirical investigations have included short-term memory, with many not discriminating well between short-term and working memory. Likewise, several assessment instruments are structured in ways that confound the measurement of short-term and working memory.

Controversies Surrounding Working Memory

Some psychologists question the working memory construct itself. Unlike short-term memory, it is more difficult to prove that working memory is a unique cognitive entity.

For example, working memory has been viewed as essentially the same as focused attention, executive processing, and linguistic processing.

Moreover, we have much to learn about some of the subprocesses that comprise the working memory system. For instance, the functioning of phonological short-term memory and verbal working memory is well documented but there remains considerable cloudiness regarding the executive functions of working memory.

In addition to these uncertainties, there has been an ongoing dispute over the distribution of working memory resources. Some researchers argue that there is a single pool of resources shared by all short-term and working memory components, whereas others advocate for separate capacities for each component.

Furthermore, the debate over the immutability of working memory capacity is far from settled. Some recent research has indicated that capacity can be increased; however, most evidence-based interventions for working memory focus on increasing its efficacy.

Regarding the relations between working memory and academic learning, overwhelming evidence has unequivocally established learning’s dependence on working memory.

With learning, about the only dispute that remains is whether students with learning disabilities have diminished working memory capacity or are simply not using their working memory resources efficiently.

Working Memory Measurement

Since the early days of psychology Opens in new window, when more children began attending school for longer periods of time, the existence of individual differences in mental capabilities, including memory, has been apparent.

In 1905, Binet and Simon included short-term memory subtests in their seminal intelligence scale. Wechsler did the same with the introduction of his first scale in 1939. Despite the early start, the development of broad-based memory scales did not occur until nearly the end of the Twentieth Century.

Within the past 15 years, interest in the measurement of working memory has corresponded with several new options. For example, the most recent revisions of intellectual scales have incorporated “working memory” measures for the first time. Also, batteries designed for the comprehensive assessment of working memory have been introduced.

Unfortunately, now that we have the measurement technology for working memory assessment, the usefulness of school-based cognitive testing is being challenged, especially in regards to assessment for learning disabilities.

The apparent decline in regards to assessment of school-based cognitive testing is primarily the result of dissatisfaction with the ability-achievement discrepancy approach to identifying learning disabilities.

However, some of the “blame” for the impending decline in cognitive testing can be placed on the structure of intellectual scales and an overemphasis on IQ scores. Although measures of general intelligence are strong predictors of academic learning and success in life, an IQ score leaves many questions unanswered.

In particular, an IQ score fails to explain why some students with normal intelligence have extreme difficulties learning. Furthermore, IQ scores provide little direction regarding the selection of interventions that might benefit individual students.

At the forefront of working memory assessment are multiple-factor instruments that allow investigation of the subprocesses involved in short-term and working memory. If we could only obtain estimates of overall working memory functioning or only one component of short-term and working memory, there would be little need for this text.

Although knowing that a working memory impairment exists is important information, it is even more helpful to know the underlying processing problem that accounts for the deficit.

For example, a working memory deficit might be due to a phonological/verbal memory deficit, a visuospatial memory deficit, or an executive memory deficit. Depending on which memory processes or components are deficient, the learning implications and the best interventions differ dramatically.

The application of the assessment methods recommended in this text, in conjunction with the use of existing test batteries (including intellectual and cognitive scales), will allow psychologists to parse and distinguish the various short-term memory nd working memory components that are so indispensable for academic learning.