IQ Summary

Increasing IQ The Effect of Working Memory Training on Fluid Intelligence

Martin Buschkuehl
Susanne Jaeggi
John Jonides
University of Michigan

What do we mean by fluid intelligence...

Fluid intelligence refers to the ability to reason and to solve new problems independently of previously acquired knowledge. Fluid intelligence is often contrasted with crystallized intelligence, which measures the extent of stored knowledge and facts (such as vocabulary).

Both types of intelligence are important for successful negotiation in a complicated world. Fluid intelligence is widely recognized as critical for a wide variety of cognitive tasks, and it is considered one of the most important factors in learning. As such, fluid intelligence is closely related to professional and educational success, especially in complex, technical and demanding environments—more and more areas of our work and personal lives.

Although performance on tests of fluid intelligence can be improved through direct practice, there has been little evidence that practice or any other regimen yields meaningful increases in fluid intelligence in adults or children. There is also a long history of research on cognitive training in psychological and educational science showing that while performance on trained tasks can improve dramatically, transfer of this learning to other tasks remains poor.

Fluid intelligence and working memory…

Working memory is the memory system responsible for storing small amounts of information for short periods of time while performing a host of cognitive tasks. Often it’s called “short-term memory.” An example is using short-term memory to do mental arithmetic; to store the partial products of the problem while working through to the solution.

In previous research, we and others have found that there is a strong relationship between fluid intelligence and working memory. Because working memory and fluid intelligence are tightly related, it would seem to make sense that training on working memory may have a beneficial effect on improving fluid intelligence.

In subsequent research, we have demonstrated a reliable dosage-dependent enhancement in fluid intelligence resulting from training on a demanding working memory task— a task that is entirely different from the tests of fluid intelligence. We have demonstrated that:

  • Transfer from working memory training to fluid intelligence does take place, and that
  • The intelligence gain critically depends on the amount of training; the more training, the more improvement in fluid intelligence.

Thus, in contrast to many previous studies, we conclude that it is possible to improve fluid intelligence without practicing the testing tasks themselves, opening a wide range of applications in education.

Working memory training in children…

Our research has now moved on to studying the effects of working memory training in children. There are numerous studies demonstrating that working memory capacity is highly related to performance on a number of specific school-relevant abilities such as vocabulary, language comprehension, reading ability, and mathematical problem solving skills. The evidence suggests that limitations in working memory capacity directly constrain the ability to learn complex skills and to acquire new knowledge.

Further, working memory is significantly affected in Attention-Deficit Hyperactivity Disorder (ADHD); a common developmental disorder associated with academic achievement difficulties and drop-out rates. Thus, an intervention targeting working memory processes in children is of high interest.

In an ongoing study, we trained elementary and middle school children on a working memory game over a period of four weeks. Preliminary results indicate that our training is effective in improving attentional and working memory-related performance, as well as scholastic skills such as mathematical abilities. It seems that training performance is directly related to improvement in reasoning skills.

The next step is to test our methodology with thousands of students to see if the laboratory results can be duplicated in real world school settings.

We are teaming with BrainX ( to create a working memory training system for schools. The system will include standardized pre- and post- training assessments. The BrainX Personal Digital Tutor technology will adapt the training to the abilities and needs of each student.

Students, their parents, teachers and administrators will be able to accurately measure increases in working memory capacity produced by the training and correlate the improvements to changes in academic performance.

To conclude, we think that working memory training can be beneficial in improving general skills and learning abilities, especially in students with working memory deficits and with special needs such as ADHD.

Author Biographies

Martin Buschkuehl is a Post-Doctoral Fellow at the University of Michigan. He received his Ph.D. from the University of Bern, Switzerland. His main interest lies in the development and design of cognitive training paradigms where he investigates generalizing effects of trained tasks to untrained ones. He is interested in applied aspects of working memory training in terms of task and software development, but also, he aims to put forward a theoretical understanding of such generalizing effects. In his studies, Dr. Buschkuehl trains healthy young adults, but also older adults, normally developing children, children diagnosed with ADHD, and patients with brain injuries.

Susanne Jaeggi is a Post-Doctoral Fellow at the University of Michigan. She received her PhD from the University of Bern, Switzerland. Her interest lies in the investigation of capacity limits of working memory. She aims to understand the behavioral as well as the neural consequences when performance is at capacity limits, and also, when capacity limits are exceeded. Further, she investigates whether and how working memory capacity can be improved and whether such improvements have generalizing effects to other cognitive domains. In these studies, Dr. Jaeggi aims to understand the cognitive and neural mechanisms that underlie training-related changes.

John Jonides is the Daniel J. Weintraub Professor of Psychology and Neuroscience at the University of Michigan. In addition, he is co-Director of the functional Magnetic Resonance Imaging Laboratory and associate editor of the journal, Psychological Science. He obtained his Ph.D. from the University of Pennsylvania. For over 25 years, Dr. Jonides’ research program has been concerned with understanding many aspects of working memory, cognitive control, and higher mental functioning. Included in that program has been a substantial body of work to chart the characteristics of information storage in working memory and how that information can be manipulated for various cognitive tasks. Also included is more recent research concerning the mechanisms of executive processing and the plasticity of these mechanisms. Dr. Jonides’ makes use of both behavioral and neuroscientific techniques in his work to investigate both psychological and neural mechanisms of memory and other cognitive processes.