Abstract

Given the ubiquity of numbers in modern society, it is comparatively surprising how little attention the investigation of number processing skills has received by the neuroscientific community, especially when compared to reading.

During the past seven years we have investigated different aspects of the human ‘number sense’ with behavioral as well as with neuroimaging methods, such as functional magnetic resonance imaging. Although a few brain areas subserving number processing, such as, in particular, the intraparietal sulcus and the left angular gyrus, have been identified, their precise function is still unclear.

In the last four years, we tested specific hypotheses about their function, exploiting differences within as well as between individuals. As an example for the former, we used learning by repetion in arithmetic. We could confirm that the left angular gyrus plays an important role in the retrieval of the solution from long-term memory, and that it also shows some domain specificity for arithmetic fact knowledge. With regard to interindividual differences, we found that mathematical ability also modulated brain activation in performing arithmetic systematically. Mathematically skilled individuals appeared to rely more strongly on memory retrieval in solving arithmetic problems than less skilled individuals.

In our most recent experiments we investigated how preferred cognitive style and calculation strategy influenced performance and brain activation in arithmetic. With this research we would like to demonstrate that interindividual differences between participants, which have long been considered a liability rathern than an asset in brain imaging research, can be used productively to test specific hypotheses about brain function.