In a typical classroom, you’ll find children who are exceptionally good at math while some struggle. Some kids seem to be particularly poor at math, though, showing difficulty even when routinely adding or subtracting even after extensive schooling. A pair of researchers at Georgetown University Medical Center and Stanford University made an extensive review of the current literature and found evidence of a form of ‘math disability’, which is related to dyslexia. Their theory suggests math disability is linked to abnormalities in brain areas supporting procedural memory.
The two researchers identified the basal ganglia and areas in the frontal and spatial lobes as responsible for the inability of some people to process math problems. These brain structures have been previously linked to dyslexia, which makes people struggle with word order and reading.
These brain structures are involved in procedural memory, a specialized learning and memory system that is crucial to automatization and non-conscious skills like driving.
“Given that the development of math skills involves their automatization, it makes sense that the dysfunction of procedural memory could lead to math disability. In fact, aspects of math that tend to be automatized, such as arithmetic, are problematic in children with math disability. Moreover, since these children often also have dyslexia or developmental language disorder, the disorders may share causal mechanisms,” said Michael T. Ullman, PhD, professor of neuroscience at Georgetown, in a statement.
Previously, other groups have suggested that problems in solving seemingly simple math might arise due to deficits in spatial short-term memory, which makes it difficult to keep numbers in mind. But this hypothesis doesn’t explain math disability in terms of underlying brain structures since the disorder must ultimately depend on a brain-related aberration.
Ullman and Tanya M. Evans, who is now a post-doc fellow at Stanford, have come up instead with what they call the “procedural deficit hypothesis.” Their idea is based on current literature that says learning a skill involves both procedural and declarative memory.
“We believe that learning math is likely similar to learning other skills,” Evans says. “For example, declarative memory may first be used to consciously learn how to drive, but then with practice driving gradually becomes automatized in procedural memory. However, for some children with math disability, procedural memory may not be working well, so math skills are not automatized.”
Math, reading or learning a new language depend on both of these learning systems and evidence so far seems to indicate that when procedural memory is impaired, a child may face math disability, dyslexia or developmental language disorder. Declarative memory often compensates but only to an extent.
“We believe that understanding the role of memory systems in these disorders should lead to diagnostic advances and possible targets for interventions,” Ullman said. “In fact, aspects of math that tend to be automatized, such as arithmetic, are problematic in children with math disability. Moreover, since these children often also have dyslexia or developmental language disorder, the disorders may share causal mechanisms.”
That’s not to say, however, you have an underlying brain abnormality if you did poorly in math in school. Maybe you had the bad luck of dealing with a teacher whose technique relied too heavily on rote memorization isolated from meaning, maybe you weren’t exposed to the right curricular materials or just maybe you’re not that bad at math as you think.