Working memory is the ability to temporarily hold information in mind and mentally work with it. It’s crucial for learning, reasoning, and comprehension. People with poor working memory tend to struggle with those cognitive tasks. This leads to an obvious question – does poor working memory translate to lower IQ?
What is working memory?
Working memory involves storing small amounts of information for a short time and manipulating it. For example, remembering a phone number long enough to dial it requires working memory. So does doing a mental calculation like (32 x 15) without pen and paper.
Working memory is often compared to short-term memory, but they are not quite the same. Short-term memory is just passive storage of information for a few seconds or minutes. Working memory is more active – it involves both storing and processing information.
Working memory has a limited capacity. Most people can hold about 7 pieces of information in their working memory at once. People with excellent working memory may be able to hold 9 or 10 items. In contrast, long-term memory has a much larger capacity.
Types of working memory
There are different types of working memory based on the information being processed:
- Verbal working memory – storing and processing verbal/language-based information
- Visuospatial working memory – storing and processing visual and spatial information
- Auditory working memory – storing and processing sounds and audio information
So for example, remembering a list of words uses verbal working memory. Visualizing how a pile of blocks will look if you add or remove some engages visuospatial working memory. Listening to a song and recalling the notes involves auditory working memory.
Working memory and IQ
IQ or intelligence quotient is a measure of general cognitive abilities, including reasoning, problem-solving, learning and comprehension. Many IQ tests explicitly assess working memory using short-term memory tasks like digit span. So working memory capacity is inherently linked to IQ scores.
But could weaknesses in working memory directly lower your IQ? Research suggests the answer is yes:
- Studies show working memory capacity and IQ scores are strongly correlated – people with high working memory tend to have higher IQs.
- Training working memory can improve fluid intelligence (ability to solve new problems), a key component of IQ.
- Disorders like ADHD that impair working memory also lead to lower IQs on average.
So poor working memory does seem to limit a person’s ability to perform well on IQ tests. However, the relationship is not completely straightforward for several reasons discussed below.
Reasons working memory may not reflect IQ
There are a few key caveats about the link between working memory and IQ:
- IQ tests measure many cognitive skills besides just working memory.
- Working memory is domain-specific – verbal, visual etc. Overall IQ relies on integrating across domains.
- Working memory capacity is malleable and can be improved with training, whereas IQ is considered more fixed.
- IQ includes stored knowledge, but working memory focuses only on temporary information.
So working memory is just one component of intelligence. Somebody can have excellent long-term memory and reasoning but poor working memory. Their IQ may still be above average overall.
Academic performance
If working memory directly impacts IQ, it should also affect academic abilities which rely on learning, reasoning and concentration. Indeed, research shows:
- Children with better working memory get higher grades in school.
- Working memory at age 10 predicts academic performance 6 years later.
- College students with higher working memory get better grades, even when IQ is accounted for.
So just like IQ, academic performance does depend significantly on working memory capacity.
Everyday cognition
Beyond formal IQ tests and grades, working memory also influences daily mental skills:
- Remembering directions, instructions or conversations.
- Keeping track of tasks, deadlines and appointments.
- Understanding complex information and situations.
- Solving problems that require holding details in mind.
- Learning new skills like driving, cooking or assembling furniture.
So poor working memory affects everyday cognition in many ways that extend beyond just IQ scores. The inability to juggle multiple pieces of information in mind can make many common tasks challenging.
Brain imaging studies
Functional magnetic resonance imaging (fMRI) allows researchers to observe how different parts of the brain get activated during working memory tasks. These studies reveal:
- Individual differences in working memory are linked to activity in frontal and parietal brain regions.
- The same regions activate during both working memory tests and problem solving tests that measure fluid intelligence.
- People with higher IQs tend to display more coordinated activity between working memory and decision-making brain areas.
The overlapping brain activation patterns support the link between working memory, IQ and intellectual functioning.
Causes of poor working memory
Poor working memory can have various underlying causes:
- Genetic factors – Neurotransmitter-related genes influence working memory capacity.
- Developmental disorders – Conditions like ADHD, autism, dyslexia often involve working memory deficits.
- Brain trauma or stroke damaging frontal lobe regions for working memory.
- Aging – Declining working memory is one of the first cognitive effects of normal aging.
- Stress, sleep deprivation, depression and mental fatigue can deplete working memory resources.
Problems with working memory tend to start early in childhood and persist into adulthood as a relatively stable trait in individuals.
Ways to improve working memory
It is possible to enhance working memory ability through dedicated practice and training. Some evidence-based approaches include:
- Working memory training games and programs.
- Mindfulness and meditation to reduce cognitive overload.
- Aerobic exercise and sports to boost executive functions.
- Getting adequate sleep to restore cognitive capacity.
- Training in memory techniques like chunking and association.
Certain medications and behavioral therapies can also improve working memory deficits caused by specific conditions like ADHD.
Conclusion
Working memory capacity is strongly predictive of performance on IQ tests as well as academic and professional achievement. People with poor working memory struggle with many aspects of learning and intellectual functioning. There are multiple causes for working memory deficits, but the good news is training can help strengthen these cognitive skills.
References
Alloway, T. P., & Alloway, R. G. (2010). Investigating the predictive roles of working memory and IQ in academic attainment. Journal of experimental child psychology, 106(1), 20-29.
Jaeggi, S. M., Buschkuehl, M., Jonides, J., & Perrig, W. J. (2008). Improving fluid intelligence with training on working memory. Proceedings of the National Academy of Sciences, 105(19), 6829-6833.
Klingberg, T., Forssberg, H., & Westerberg, H. (2002). Training of working memory in children with ADHD. Journal of clinical and experimental neuropsychology, 24(6), 781-791.
Kuwajima, M., & Sawaguchi, T. (2010). Similar prefrontal cortical activities between general fluid intelligence and visuospatial working memory tasks in preschool children as revealed by optical topography. Experimental brain research, 206(4), 381-397.
McNab, F., & Klingberg, T. (2008). Prefrontal cortex and basal ganglia control access to working memory. Nature neuroscience, 11(1), 103-107.
Olesen, P. J., Westerberg, H., & Klingberg, T. (2004). Increased prefrontal and parietal activity after training of working memory. Nature neuroscience, 7(1), 75-79.