Sarah Jenks:
Is intelligence learned or is it genetics? Lately researchers have begun studies where they compare MRIs of people's brain to their IQ levels. They studied how the amount of gray matter in the different sections of the brain correlated to how smart they were. This testing worked for men, but the study on women showed a higher correlation to their white matter, indicating that different sexes use different pathways to think. These studies showed a strong connection between high IQ and the size or shape of the superior parietal lobe and the prefrontal cortex. These parts of the brain however are not involved in memory or information storage, but rather in planning, personality, thinking, and perception. This indicates that what makes someone a genius is not their brain's ability to process and store info quickly, but rather their brains use a number of senses to make sure they are most efficient, focusing only on what is needed.
http://www.cnn.com/2006/HEALTH/09/11/gupta.genius/index.html?iref=newssearch