Read our COVID-19 research and news.

Finding the Prime Factors in Number Processing Deficits

Daniel Ansari (Courtesy of Daniel Ansari)

About 5% of children have a learning disability known as developmental dyscalculia, which interferes with the processing of numerical information. That's about the same prevalence as dyslexia, and yet dyscalculia has received a fraction of the research attention. "There's a terrifying statistic that shows that the ratio of papers on dyslexia to those on dyscalculia is 14 to 1," says cognitive neuroscientist Daniel Ansari of the University of Western Ontario in London, Canada. That disparity is troubling, he says, because "individuals and society at large pay a large price for low numerical and mathematical skills." Low numeracy is not only a strong predictor of school success but also associated with worse health care, greater likelihood of criminal behavior and incarceration, and higher risk for depression and other illnesses.

"Working in an education department whose stated goal was to forge greater connections between education and cognitive neuroscience, naturally, you start thinking hard about how you can help to achieve this goal and thereby do your job." -- Daniel Ansari

Figuring out the brain basis of numerical and mathematical abilities, what causes dyscalculia, and how to remedy the disorder are the central aims of Ansari's work. Using a combination of behavioral and neuroimaging methods, he and his colleagues examine how children develop foundational number-processing abilities, such as the ability to judge which of two numbers is larger or to estimate numbers' position on a number line; why these basic cognitive processes sometimes go awry; and how to help children with serious deficits in numerical processing.

Ansari first became interested in numerical processing as a graduate student in cognitive developmental psychology at University College London (UCL). There, he worked with Annette Karmiloff-Smith, an expert in developmental neurocognition who had recently received a grant to study number processing in children with Williams syndrome, a rare genetic disorder that can lead to a puzzling cognitive profile: a relative strength in language coupled with severe deficiencies in visual-spatial cognition and number processing. "Working with children who have tremendous difficulties across a number of domains, including numerical cognition, you start to wonder: How does my science matter? And how can you apply what you learn in the laboratory to real-world problems?"

Special Issue: Early Childhood Education

This article coincides with a special issue of Science devoted to the topic of early childhood education. We recommend this companion article from Science Careers and encourage you to explore the other parts of the special issue.

A year into his Ph.D. program at UCL, Ansari interrupted his studies to pursue a master's in neuroscience at the University of Oxford in the United Kingdom. "I looked at people like [cognitive neuroscientist] Stanislas Dehaene, whose research illustrated the value of using neuroscience to ask questions about numerical cognition and knowledge acquisition, and I said, 'I want to do this too.' "

After finishing his Ph.D. in 2003, Ansari planned to take a psychology postdoc position at Harvard University. Then he saw an ad for a faculty post focused on numerical cognition in Dartmouth College's Department of Education. "It was this amazing opportunity," he says. Dartmouth had an exceptionally strong group of cognitive neuroscientists and was the first institution in the United States to acquire a functional magnetic resonance imaging machine dedicated to research. The university's education department had recently rebranded itself to embrace the fledgling field of mind, brain, and education.

There were disadvantages to the plan. Taking a job at Dartmouth likely would mean geographic separation from his wife, who was applying to Ph.D. programs in historical musicology. And with only two publications to his credit and his thesis not yet complete, he considered himself a long shot.

The gamble paid off. He got the job, and when his wife was accepted at Harvard, they were relieved that despite the distance between Hanover, New Hampshire, and Cambridge, Massachusetts, they would at least be in the same time zone. As Ansari settled into his first faculty job, he started thinking seriously about educational applications of his work. "Working in an education department whose stated goal was to forge greater connections between education and cognitive neuroscience, naturally, you start thinking hard about how you can help to achieve this goal and thereby do your job," he says. The education-neuroscience connection worked both ways: His work with schools sparked an interest in brain plasticity. "By studying how education changes the brain, we can find out how this uniquely human experience induces change in both brain structure and function -- something we cannot do with animal models."

The transition to an education department wasn't easy. "I was at a complete loss for about 2 years," Ansari says. "There was so much that I had to learn about education." His teaching load included classes far outside his research expertise, from introduction to education to human development and education across cultures. "I would work most of the day on my research and then read and prepare classes into the early hours of the morning," he remembers. "I was constantly anxious about being able to do what I was asked to do."

That struggle constrained his research. "In the early years, I had great trouble getting my research published, and I was starting to think that maybe I would not be able to do this and get to a stage where I could call myself an independent researcher." He also encountered strong resistance from some researchers in his own department. "A number of colleagues who had been there for a long time were actively trying to put roadblocks in the way of building a department that was committed to the bridging between neuroscience and education," Ansari remembers. "I think there was a real fear among these individuals that neuroscience was taking over and leaving behind what they had been doing in the department for many years."

Ansari found refuge with some junior faculty members and postdocs in Dartmouth's Department of Psychological and Brain Sciences. But his most important professional relationship was with a junior colleague in his own department, Donna Coch. Coch, who is now the department's chair, had a Ph.D. in education and had done a 2-year postdoc; her familiarity with education departments, and her greater experience, buoyed her colleague. "We spent hours talking about how we might make mind, brain, and education happen at Dartmouth," he says. "We were the only two junior faculty in a small department with a total of five full-time faculty members. We did not get much mentoring from our senior faculty, so we really had to stick together." Their conversations culminated in a 2006 Trends in Cognitive Sciences paper in which they discussed new models for training researchers and practitioners in mind, brain, and education.

In 2006, Ansari moved to the University of Western Ontario. "I came here because I was offered a Canada Research Chair position, which allows young scholars to devote more of their time to research," Ansari says. There, he found "a very supporting and collegial atmosphere," he says. Although his primary appointment is in psychology, he is cross-appointed in the education department. He also interacts with the general educational community in Ontario.

His research spans basic and applied realms. He and his colleagues have found that performing basic numerical and mathematical tasks triggers atypical patterns of brain activation for children with dyscalculia. He and colleagues at the University of Waterloo have found that even the most basic number-processing abilities, such as number comparison and counting, are disrupted in individuals with math anxiety. He is also studying how children learn to ascribe meaning to the many arbitrary symbols that litter math textbooks; without this ability, children quickly fall behind in math, and educators may fail to recognize why. His group is also planning longitudinal studies to identify the brain and behavioral characteristics that distinguish children who will have persistent numerical and mathematical deficits from those whose problems are more transient. He's now beginning to design diagnostic tools to test children's foundational number-processing abilities.

Despite the stress and uncertainty he experienced starting out, Ansari isn't sure he would do anything differently if he were starting again. "Looking back, I think those years were really formative, and I had to go through this pain threshold," he says. "I feel proud to say that I did it on my own, even if it was hell sometimes. I guess that is one of the ways you grow."

Siri Carpenter writes from Madison, Wisconsin.