The way we do math evolves as we grow older; as little children, we start off by relying on counting using fingers before moving on to more efficient memory-based strategies as we grow older. This transition is a well-documented hallmark of children’s cognitive development in arithmetic, but the changes in our brain underlying it still largely remain a mystery.
Scientists from Stanford University, U.S., looked to fill in some gaps by comparing brain activities of children aged seven to nine years old, adolescents (14 to 17 years old) and adults (19 to 22 years old). Children who were again evaluated after 14 months clearly demonstrated the change — a reduced reliance on fingers to count and increased use of memory-based strategies.
Using data from an imaging technique called functional magnetic resonance imaging (fMRI) they discovered that the fluctuating activity of a part of our brain called the hippocampus plays a key role in this shift in problem-solving strategy. Additionally, they discovered that that the strength of connectivities between the hippocampus and the neocortical region of the brain reflects differences in individual arithmetic skills among children.
“The hippocampus has a critical, but time-limited, role in the early phase of knowledge acquisition,” say the authors in a paper published this week in Nature Neuroscience. But most of the evidence is based on animal studies, and not much is known about how the hippocampus supports the shift from counting to memory-based problem solving in individual children.
The scientists used fMRI scans to find out which parts of the brain were activated and to what extent across the three age groups. The data revealed that older children showed increased activation in the hippocampus and, as suspected, reduced activation in the regions of the brain known to be involved in counting – the prefrontal and parietal cortices.
The team also noticed that after the period of increasing hippocampal activity in childhood, there is a subsequent period of decrease towards adolescence. From then on, it was the degree of hippocampal connectivity with the rest of the brain that seemed more important for mathematical aptitude.
Increased hippocampal connectivity was also found to explain why some children were better at problem-solving than others.
Vinod Menon, one of the authors of the studies, said to Nature News that their findings may have implications not just for the development of math skills, but also other types of learning in children. However, the authors agree that further research, possibly with higher-resolution imaging techniques, is needed to understand the nature of the information being passed on from the hippocampus.
