What Is Working Memory Capacity?
Working memory capacity is best understood as the ability to build and maintain temporary bindings between elements, which strongly predicts fluid intelligence.
Source
What is working memory capacity, and how can we measure it?
What they did
The researchers tested 262 participants (of which 56% were female) to understand the structure of working memory capacity. Each participant completed two cognitive testing sessions that lasted about 3 hours each, with a time interval between sessions ranging from 4 to 6 days. The test battery measured complex span performance, memory updating, information binding, secondary memory, response inhibition, and fluid intelligence.
What they found
The study found that complex memory span, memory updating, and information binding tasks are highly integrated indicators of a general working memory capacity (WMC) factor. This general WMC factor is strongly correlated with fluid intelligence, showing a correlation of 0.83, and is also highly correlated with secondary memory at 0.79. In contrast, the specific cognitive conflict tasks designed to measure response inhibition did not show significant correlations with working memory capacity.
The limits
What it doesn't show
This study does not establish a causal relationship between working memory capacity, secondary memory, and fluid intelligence because it relies entirely on correlational data. It also does not prove that all types of executive control are unrelated to working memory capacity, as it specifically measured response inhibition using only two paradigms. Additionally, the findings might not generalize universally across all ages, since the sample's average age was 27.41 years.
Key terms
- Working memory capacity (WMC)
- An individual differences construct reflecting the limited capacity of a person's working memory system to hold and manipulate information.
- Complex span paradigm
- A class of memory tasks requiring participants to store a list of items while simultaneously performing an unrelated processing task.
- Executive attention
- A cognitive system responsible for using attention to actively maintain task-relevant information or suppress task-irrelevant distraction.
- Primary memory
- A highly limited active maintenance component that stores and keeps a small number of items immediately accessible.
- Secondary memory
- A long-term storage component from which information must be retrieved using cue-dependent search processes.
- Binding hypothesis
- The theory that working memory capacity is limited by the ability to rapidly construct, maintain, and update temporary associations between items and their contexts.
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Quiz yourself
How do the authors distinguish between working memory and working-memory capacity (WMC)?
Common questions
What is the main difference between primary memory and secondary memory in this study?
Primary memory is a highly active, limited-capacity workspace used for immediate maintenance, whereas secondary memory holds larger amounts of information over longer durations and requires active retrieval cues to access.
Why did the researchers use structural equation modeling (SEM) instead of simple correlation?
SEM allowed the researchers to group multiple tasks together into latent factors, which isolates the true cognitive constructs of interest by filtering out the random errors and specific quirks associated with any single task.
How does the "binding hypothesis" explain why we forget things in working memory?
It proposes that forgetting is caused by interference between temporary bindings (such as associating a specific word with its position on a list), rather than the absolute decay of information over time.
Does having a high working memory capacity mean you have superior response inhibition?
No, this study found no significant relationship between working memory capacity and the specific ability to inhibit incorrect responses in cognitive conflict tasks like the Simon or Flanker tasks.
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