Do different working memory tasks measure the same thing?
Different working memory tests do measure the same underlying mental capacity once measurement errors and task-specific differences are statistically controlled.
Source
A task is a task is a task: putting complex span, n-back, and other working memory indicators in psychometric context
What they did
The researchers evaluated 101 younger and 103 older adults using nine different working memory tasks representing several distinct experimental paradigms. To validate their findings against a broader cognitive ability, they also had participants complete nine reasoning tasks. They used structural equation modeling to separate task-specific variance and measurement error from the shared working memory construct.
What they found
They found that after controlling for task-specific differences and errors, the underlying factors for complex span and n-back tasks correlated at 0.69 in both age groups. Furthermore, the general working memory factor accounted for 71% of the variance in reasoning for younger adults, and 83% for older adults. When using fewer, more similar tasks to measure working memory, the correlation with reasoning was weaker, showing that a diverse mix of tasks provides a better measure of the construct.
The limits
What it doesn't show
The study does not establish causal mechanisms, meaning it cannot prove whether working memory capacity directly drives reasoning ability or if both are influenced by a third cognitive variable. Because the participants were restricted to healthy younger adults aged 20 to 31 and cognitively healthy older adults aged 65 to 80, the results might not generalize to children, clinical populations, or other age groups. Additionally, the research relies on a specific set of lab paradigms and does not prove that all possible working memory tasks will fit this hierarchical structure equally well.
Key terms
- Working Memory
- The cognitive system responsible for temporarily holding and manipulating information.
- Complex Span Task
- A working memory test that requires participants to remember a list of items while simultaneously performing an unrelated processing activity.
- N-back Task
- A working memory test where participants indicate whether a current stimulus matches the one presented a specified number of steps earlier in the sequence.
- Latent Factor
- A hidden variable that is not directly observed but is inferred through mathematical modeling from other directly measured variables.
- Measurement Error
- The difference between the actual value of a quantity and the value obtained by a measurement task.
- Paradigm-specific Variance
- The portion of test score variability that is unique to the specific design or format of a test rather than the construct it aims to measure.
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Quiz yourself
Prior meta-analytic research found what average raw correlation between complex span and n-back tasks?
Common questions
Why do different working memory tasks sometimes show very low correlations?
Individual tasks contain a lot of noise, including measurement errors and details specific to that particular test or format. When these non-essential differences are statistically removed, the underlying correlation between the actual working memory demands of the tasks is much stronger.
What is the advantage of using a diverse battery of working memory tasks?
Using a diverse range of tasks covers the overall cognitive construct more broadly, reducing the impact of task-specific quirks and leading to a more accurate measure that correlates better with other abilities like reasoning.
How does aging affect the measurement of working memory according to this study?
The structure of working memory remained highly similar across both younger and older age groups, though all tasks measured general working memory about equally well in older adults, while younger adults showed some differences in task performance.
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